Looking on the office shelf, I can see a copy of Illustrator CS WOW! books ranging from CS through to CS4. I only joined the Adobe Illustrator crowd at version 10, and when CS appeared back in 2003, I wanted to learn a little more and it was Sharon Steuer’s book that I reached out for. I found it invaluable and it became part of a process which culminated in the launch of the Phantasm CS plugin for Illustrator.

Today is a good day because this morning I received the latest incarnation of the long-running series: The Adobe Illustrator CS5 WOW! Book published by Peachpit Press.

Immediately I thought the cover was one of the best and makes powerful use of the new brush tools introduced in Illustrator CS5. It’s hard to image that the artwork is vector based and could be expanded to the size of a ocean liner!

I have to confess to Sharon that even though I was one of the reviewers of chapters as the book was being assembled, I didn’t have time in the past year to read a good portion. Therefore a large amount is new to me and I’ve already gleaned valuable nuggets and snippets of information and tips. This is the great thing about this book and why I’ve kept with every edition; it’s an invaluable resource for novices and experienced users alike.

With thanks to…

Sharon naturally contributes material to the book, but her task is mainly of editor, compiling a vast array of tutorials, artwork and tips from accomplished and well know Illustrator users. The breadth of designers ensures that all material is varied, with a style or approach for everybody. This is demonstrated by contributions ranging from Von Glitschka (who created the infamous “Loyal Order of Wormwood” example artwork that accompanied Illustrator CS4 – still my favourite sanctioned demonstration piece) to Anil Ahuja – one of Adobe’s own developers. It would seem that Anil was part of the team that developed the Illustrator CS5 perspective grid/tool system as his contribution – a 3D bus illustration – makes excellent use of it.

I’m sure you’ll be familiar with other contributing designers including Ryan Putnam of Rype Arts. The Acknowledgements page reads as a bit of a “who’s who” of the Adobe Illustrator world.

I know that technically all material in the book of a high quality, because this is where Jean-Claude Tremblay was involved as technical editor. Jean-Claude is an Adobe-certified consultant and trainer based in Canada and runs Proficiografik specialising in Illustrator and InDesign. I, and many others, have learnt a lot from JC over the years from forums and other guidance. As Illustrator is a such a technical package at heart, this task must have been a bit daunting.

286 pages, plus…

You would reasonably expect 286 color pages to be sufficient. Not for Sharon and the team who appears to have found time to cram the accompanying CD full of great additional material. And I’m not just referring to the odd artwork file; there are pages of additional appendices, tutorial material, original artwork featured throughout the book and more. It’s going to take me a long time to sift through all this.

It’s such a great benefit to access some of the original files featured. Reading explanations obviously gives a very good idea, but nothing beats supporting words with messing around for yourself with the exact same objects and artwork constructs.

Conclusion

You can probably guess that I like this book. I’ve only spent some hours reading it physically in front of me and I’m sure it’s going to stay on the desk from weeks to come. I don’t want to miss a trick.

If you’re serious about learning Adobe Illustrator – experienced user or not – go out and get this book!

ISBN-10: 0-321-71244-7
ISBN-13: 978-0-321-71244-8

Nicholas van der Walle

Following a long-running thread on the Adobe Illustrator forum [click here to read], it emerged that there are different methods to measure the area of a vector path within Illustrator. It was interesting to see that each approach was different – and free – and included a plugin and a hidden window within Illustrator intended for debugging by the development team. Each of the two methods has it own advantages, but both have the same disadvantage; they can only provide a result for simple paths – not compound paths, clipped paths, etc.

In this tip, we’ll have a look at both previously-disclosed methods plus a third option making unique use of Phantasm CS Publisher’s advanced Ink Coverage tool which caters for all object types, including compound paths, editable text, groups and even images!

Important notes:

• Each method detailed here is available right up to Illustrator CS5 on both Windows and Mac.
• Astute Graphics does not provide warranty or support for the non-Phantasm CS Publisher methods provided here. Astute Graphics accepts no responsibility whatsoever for any loss or damage resulting in the use of these methods.

Telegraphics PathArea Filter

Toby Thain of Teleghraphics has kindly produced a series of free Photoshop and Illustrator plugins. The one entitled PathArea Filter is the one we’ll be looking at here.

This Filter is accessed via the Filter menu. In Illustrator CS3 and below, the Filter menu could be found at the top level (File… Edit… Object… etc.). However, since the release of Illustrator CS4, if a 3rd party Filter plugin is installed (such as this PathArea Filter or our very own Phantasm CS) Adobe moved this to become a sub-menu of Object as may be seen below:

Again, having selected a single non-compound path and opting for … » Filter(s) » Telegraphics » Path area, the following information window will be displayed:

It’s interesting to note that not only is path’s area provided, but also the path’s perimeter length which can prove equally useful.

Note: if a compound path is selected, this Filter will return the total area as if the two (or more) paths that form the shape were separate.

Illustrator debugging window

This is where things become a little less official. The Illustrator debugging window was revealed by Teri Pettit, probably the longest serving Illustrator developer, in the Illustrator forum posting. It’s critical that before using this method, you understand that this was never intended for general use by the public, so it’s essential that you save your document before trying it out.

First select a single path. The debugging window is then accessed on the Mac by pressing Cmd-Shift-Option-F12. On later Mac keyboards where the volume button also features on the F12 key, you may also need to hold down the fn key at the same time! With Windows, the keypress is an equally impressive combination of Ctrl-Alt-Shift-F12. Enlarge the debugging window and click on the bold path text right at the bottom. The information of the path object (most of it obscure) which contains the path’s length and area in point units is displayed as below:

We’ve not covered this method in greater detail as the IllustratorHints website has done just that.

Phantasm CS Publisher

Both previously mentioned solutions are free and do exactly what they’re intended for when it comes to single paths. For the majority of situations, this is likely to be all that’s required and the results are accurate and very easy to access. However, they are more restricted when it comes to compound paths (it’s possible that compound paths which don’t intersect such as the letter “O” could be calculated manually) and can’t perform the task on all other object types.

The method about to be outlined makes use of Phantasm CS Publisher’s more advanced Ink Coverage menu where numeric area values are returned for each ink present in the artwork. This tool will be used to gain area information for any kind of embedded object within the Illustrator document. We’ll be using the following simple example of the letter “E” (which is still editable text – not outlined) plus an underlying image where we want to add the image’s areas of color, but not the background white, into the result:

It’s important to remember that this doesn’t form the Ink Coverage tool’s intended purpose so the process is longer than the previously described methods. Also, the Ink Coverage tool provides approximate results and is not as accurate on simple single paths as the previous methods.

Steps to follow:

1. Using the Swatches panel, create a new spot color, naming it “Area” and giving it any arbitrary CMYK, RGB or other color value (the color defined really doesn’t matter) as shown below:

2. Select the object(s) you wish to measure. This can include all object types and the calculation will also take into account the area occupied by strokes/outlines without first expanding. Then group these together if more than object has been selected.
3. With the object or group selected, open Phantasm CS’ Duotone live Effect tool via Effect » Phantasm CS » Duotone.
4. Click on the default orange tone’s color square to open the Color Picker window.
5. Click on the Color Swatches button (below the Cancel button) to toggle to a list of the colors and spot colors defined in the document’s Swatches panel.
6. Select the “Area” spot color previously defined and OK the Color Picker window to return to the Duotone tool.

7. Click on the Duotone curve at the 5% value and drag the new curve node to the top of the graph, or manually enter a New Tint value of 100% as shown below:

8. OK the Duotone window. This results in artwork where all areas of color are now represented as a solid tint of the “Area” spot color as shown below:

9. Now it’s possible to gain the area result from the Phantasm CS Publisher Ink Coverage tool which is opened by following View » Output Preview » Ink Coverage. The Ink Coverage window in Phantasm CS Publisher provides the approximate area results for each ink; for this exercise we’re looking for the “Area” ink value as highlighted below:

It’s possible to display the value in alternative units by using the associated pull-down menu. The results (which would also include any other ink present) can then be copied as plain text to the clipboard by clicking on the values result box and pressing Cmd-C (Mac) or Ctrl-C (Windows).

If this operation is to be repeated, it’s possible to define the Duotone as a Graphic Style which can then be instantly re-applied cutting out stages 3-8. Alternatively, you may find that rather than applying a Duotone to produce a spot color tint of the selected objects, it may be simply sufficient to use the Swatches panel to apply a fill and/or stroke with the “Area” spot color, which again would replace stages 3-8.

We hope that this method is of some use!

The folks over at Pemla Inks have passed on a link allowing those intending to attend the major US print technology trade show, Graph Expo, to obtain the passes for free (normally $30 in advance). Simply click on the following link:

www.xpressreg.net/register/GASC100/hallonly/start.asp?sc=GPH1R1A

The show is being held at McCormick Place South, Chicago, IL, USA over the following dates:

Sunday, 3 October, 10 am – 5 pm
Monday, 4 October, 10 am – 5 pm
Tuesday, 5 October, 10 am – 5 pm
Wednesday, 6 October, 10 am – 4 pm

There’s also a pre-show Executive Outlook Conference on Saturday, 2 October, 8 am – 5:30 pm

You can find out full show information at www.graphexpo.com

Astute Graphics will not be attending or involved in the show in any other form – perhaps next year depending on developments. But we know many of our customers are and we wish them a pleasant and informative time there!

This shorter article rounds off the mini-series dedicated to handling artwork for flexo printing within Adobe Illustrator using the Phantasm CS Studio and Publisher plugin. In this piece we will show a method of checking for areas of artwork which would be cut-off from the final result due to flexo printing’s ink drop-off levels.

TAC levels Correct flexo cut-off checking

It’s easy to make the mistake thinking that standard TAC (Total [Ink] Area Coverage) levels checking is appropriate for checking for cut-off levels for flexo printing. After all, TAC level checks are readily available in Phantasm CS Studio and Publisher (View » Output Preview » Ink Coverage, Adobe Acrobat Pro and more.

Sadly, this would not be accurate. TAC levels are the accumulation of all inks placed on top of each other; ie. a CMYK print process could give a maximum ink coverage level of 100% x 4 = 400% at any one point. Apart from the fact that TAC level preview systems are geared towards informing the designer of ink coverage greater than a specified level (for this flexo printing check, we need to check for coverage less than a given cut-off value), we need to check individual ink channels, not the sum total.

For example, the following linear gradient (top) would not dip below even a 10% TAC coverage level as the gradient averages out at a constant 20% TAC level:

However, if a 5% ink drop-off level was applied via a cut-off curve, it may be seen from the lower gradient that two very clear steps occur. This is because each of the CMK channels get cut-off as they blend from a 20% tint to 0%.

Method of checking for flexo ink drop-off in Illustrator

Happily, the Phantasm CS Studio and Publisher Ink Coverage and full Separations tools are flexible enough to cater for this check when combined. Therefore it becomes possible to produce visual warnings to the Illustrator designer or operator that certain areas of artwork are going to be cut-off using a flexo print method. Once alerted, it’s then possible to use the techniques discussed in this mini-series to adjust the artwork.

For this example, we’ll be checking a portion of the Phantasm CS Drinks Carton example artwork (shown left) that can be found here in PDF form. This portion of the design makes use of 6 inks: CMYK plus two spot colors.

The first step is to fully separate of the original artwork using Phantasm CS’ full Separation system (not to be confused with the Quick Separations tool or the equivalent native quick separation panel found in Illustrator CS4 or above). To do this, ensure that the Phantasm CS Separations panel is displayed (Window » Phantasm CS Separations) and click on the Generate Separations button. This will create a new Illustrator document where each ink used in the original document is separated into layers, whereupon the Phantasm CS Separations panel will update to offer full viewing control.

In the Phantasm CS Separations panel, target a single ink separation to examine for cut-off levels by holding down Alt and then clicking on the channel’s left-hand round button as may be seen below:

By holding down Alt which clicking on the separation’s button, all other separations are removed from view. Notice that the Phantasm CS full separation system automatically desaturates the ink color allowing for clearer analysis of the tint levels found in that channel.

Next, open Phantasm CS Studio or Publisher’s Ink Coverage tool via View » Output Previews » Ink Coverage and set the levels as follows:

Note that the most important value is the highlighted one, which should equate to the ink drop-off percentage value for the intended flexo print method (in this example, a realistic 3%). Set all other values higher, as per the example shown above.

Next, set the first ink level to a vivid bright color (the 0% level is always white) – in this case red was chosen by clicking on the color box and defining the color in the color picker window. Set the lower three ink levels to black.

Now, looking at the artwork Ink Coverage in the document window, the following may be seen:

Any area displayed in shades of red (or your chosen highlight color) represent areas of that particular separation in the artwork that will be cut-off using flexo printing. Areas of pure white are simply where no ink coverage for that separation occurs and isn’t of concern.

Close the Ink Coverage window, hold down Alt and select another separation using the Phantasm CS Separations panel and repeat the process on all ink channels.

Return to the original document and adjust the artwork to correct the situation using techniques covered in this mini-series.

We advise that you read the review in full [click here], but here are some great quotes:

Phantasm CS can best be summed up by saying it offers Photoshop-esque functionality to Illustrator. Want to apply Levels? Check. Need to access the Curves? Got it. Need to adjust Hue/Saturation? Bingo.

Phantasm CS … offers the user an insane array of extremely well-implemented features that you may have since long given up on having within Illustrator.

If you are a seasoned Illustrator user, trust me you will have a tough time getting used to the fact that you can do all of this right within Illustrator. As I mentioned above, your brain will tell you “can’t do that” and you will need to re-learn that you now have the capability. That’s probably the biggest learning curve for Phantasm CS.

What more is there to add?

Whilst covering drop shadows and glows in the previous object-specific flexo ink drop-off article, the matter of producing accurate cut-off levels for mixed value process CMYK shadows and glows was mentioned. The problem with generating these was due to the way in which drop shadows and glows are created internally within Illustrator (refer to details).

The best practice prescribed imposed significant limits on the shadow and glow colors possible as each ink had to be defined at 100% tint.

This article provides an Illustrator Action set that uses a clever combination of Illustrator and Phantasm CS Studio and Publisher tools. These automatically generate a cut-off drop shadow or glow based on any process CMYK color, applied to any embedded object type. The Actions, perfected over several days of testing on both Mac OS and Windows, allows this process to be completed in seconds – and all within Illustrator – as opposed to a significantly longer period if produced manually in a combination of Illustrator and Photoshop.

Note: This technique is not compatible with Illustrator CS2 or below due to a lack of Device-N (multi-ink) image support which was introduced in Illustrator CS3.

Overview of the process

As a the standard Illustrator shadow and glow live Effects defined with a mixed level CMYK color can not have an accurate cut-off level applied to each channel, an Illustrator Action set has been produced (shown, left) that modifies the shadow component and applies a pre-determined cut-off correctly. Even though the shadow or glow is therefore no longer “live” or linked to the original artwork, the Action process means that re-applying the glow takes a matter of seconds.

The Actions rely on the presence of two Graphic Styles within the Illustrator document. These are added with two clicks through the use of the Graphic Style library system within Illustrator and their availability in a persistent panel (a Graphic Style library panel that optionally re-appears in every Illustrator session). This technique was devised in an earlier article Adding Effects to Illustrator Actions.

Any operator familiar with Illustrator can easily use this process as the standard Drop Shadow and Inner/Outer Glow windows are still used to define the shadow or glow characteristics.

Video demonstration

A written step-by-step guide is provided next. However, for a quick preview of the steps necessary, the following video has been provided:

If you have problems viewing this movie, you can view the movie on the Astute Graphics YouTube channel or click on the movie file link: www.astutegraphics.com/movies/blog/flexo-process-shadow-cut-off.mov

Step-by-step guide

One-off task of adding Actions and Graphic Styles

Before you can use the Action sets to produce cut-off curves on drop shadows and glows, it’s first necessary to add the associated Actions and Graphic Styles to Illustrator. This is a one-off task and they will be automatically available for future sessions.

Firstly, download the Actions set and Graphic Styles:

ZIP archive containing Actions for both Illustrator CS3 and CS4, plus a slightly modified copy for Illustrator CS5 (6Kb)

ZIP archive containing single file with both Graphic Styles referred to in above Action, for Illustrator CS3 and above (67Kb)

Quit Illustrator, if running and then copy these files into their respective folders within:

• Mac OS: Applications » Adobe Illustrator CS(X) » Presets » [your language folder, eg. "en_GB"] » …
• Windows: C:\ drive » Program Files » Adobe » Adobe Illustrator CS(X) » Presets » [your language folder, eg. "en_GB"] » …

Restart Illustrator and ensure the Actions and Graphic Styles panels are both visible (if not, they can be found in the Windows menu).

With the Actions panel, click on the pull-down menu (shown above) and select Load Actions… and locate the Actions file. the Action set containing 5 variants of the “Process shadow” cut-off Actions should now be present and will re-appear automatically in the next Illustrator session.

With the Graphic Styles panel, click on the pull-down menu and select Open Graphic Style Library » Flexo Cut-Off Styles for Action. This will open a new panel containing two Graphic Styles which are required for the Action to work. In the new panel, click on the pull-down menu and tick Persistent which ensures that this Graphic Styles panel will appear in every Illustrator session until closed or the persistent option is toggled off once more.

These steps should not need to be repeated. However, if the Actions or associated Graphic Styles were to disappear in the future, they are always accessible in the Illustrator Presets folder.

Create a drop shadow with flexo cut-off

You are now ready to produce a drop shadow using the Action.

Open or create a CMYK document. Without any objects selected, click on both Graphic Styles that appear in the Flexo Cut-Off Styles for Action panel to import them into your document’s Graphic Styles panel. (This process needs to be done once for each document you wish to run the flexo shadow/glow cut-off Action).

Select a single embedded object (single vector, image, group…) you wish to have a drop shadow applied to. Via the Actions panel, select one of the 5 cut-off actions provided and click on the Play button:

The Action will start to run and then automatically open the Drop Shadow window. Enter the settings you want but note that the transparency mode makes no difference but may be changed from the default Multiply mode once the shadow is generated. Click OK and the Action will complete the process.

A CMYK shadow with an appropriate flexo cut-off level has been applied correctly to each channel.

To change the transparency mode of the drop shadow, simply change the type via the Transparency panel.

Adapting the Action to apply Inner and Outer Glows

The same basic Action set can easily be adapted to apply cut-off curves to both glow types. Simply replace the Drop Shadow reference in the Action:

1. It’s advisable to first replicate the original Action by dragging it to the panel’s Create New Action button
2. Click on the Action entry’s left-hand arrow to expand it so that you can see all steps
3. Select the entry Effect: Stylize: Drop Shadow
4. Click on the panel’s pull-down menu and choose Insert Menu Item… and via the standard Illustrator menus select Effect » Stylize » Inner Glow… or Effect » Stylize » Outer Glow…
5. OK this
6. Select and delete the original Effect: Stylize: Drop Shadow entry in the Actions panel

Run the Action to test.

It’s advisable to save any new or modified Action set by first selecting the Action “folder” group entry and then via the Action panel’s pull-down menu, selecting Save Actions….

Changing the cut-off curve

The cut-off levels provided should only be used as examples. It’s critical that you test, and if necessary change, the Actions provided to produce the results you require.

To change the curve in an Action is a very simple process and allows you to also define a color correction curve with a cut-off simultaneously. Here are there steps to take:

1. Ensure a document is open (it can be a new blank one)
2. Optional: first duplicate the Action if you wish to keep the original as a reference – although you can always re-load the Action set
3. Expand the Action you wish to modify via the left-hand arrow so that you can see all the steps listed
4. Double-click on the Phantasm CS Curves entry and modify the Curves graph to suit (you can also load a Photoshop-compatible curves settings file)
5. OK’ing this change completes the process

It’s advisable to save any new or modified Action set by first selecting the Action “folder” group entry and then via the Action panel’s pull-down menu, selecting Save Actions….

Shadow or glow resolution

By default, the Action produces a shadow to a 300dpi resolution, which is typically required for commercial print. It’s possible to change this value, but first you need to also ensure that the resolution defined in Effect » Document Raster Effects Settings is of the same value. Again, Illustrator sets this to 300dpi by default for a print document.

To change the resultant shadow or glow resolution, the process is similar to changing the cut-off curve:

1. Ensure a document is open (it can be a new blank one)
2. Optional: first duplicate the Action if you wish to keep the original as a reference – although you can always re-load the Action set
3. Expand the Action you wish to modify via the left-hand arrow so that you can see all the steps listed
4. Double-click on the Rasterize entry and modify the resolution value to suit
5. OK’ing this change completes the process

Caution with using different transparency types

By default the Actions define the shadow’s transparency mode as Multiply. This mode, along with the alternative Darken mode ensures that the ink levels never go below the shadow’s cut-off levels. If however, you change the transparency mode to alternative modes such as Lighten, it’s likely that you will end up with a shadow that has ink levels below the required flexo drop-off point.

Why does the Action add a spot color to the document?

The approach used makes use of an anomaly within Illustrator CS3 and above where a spot color reference made in a Graphic Style doesn’t automatically get added to the Swatches panel. In fact, if you run the Action, even though the referenced spot color has been used to generate the cut-off shadow, it doesn’t feature in the final results and therefore shouldn’t appear in the Swatches panel at in the end. However, a reference to a red Temp-spot may appear in Phantasm CS’ Quick Separations tool (not the full separations system) and Illustrator CS4 and above’s Separations panel.

If the spot color does appear unnecessarily in the Swatches panel (it should never feature when outputting the work if the Actions work correctly), simply select it and delete it. A reason it may make an appearance is if the process of generating the shadow was stepped through backwards via the undo system.

How the Actions works

This last section is for the curious and isn’t essential to understand in order to use…

It’s not possible to fully describe the entire process in detail. However, it has been very carefully developed over many iterations to ensure that the results are faithful when applied to any embedded artwork type including vector and raster images.

The basic steps used are as follows:

• Copy and paste the selection behind the original and group it (in case multiple objects were selected)
• Apply a Graphic Style of a single Duotone live Effect which references a single temporary spot ink – ie. the original CMYK artwork is now a spot color monotone maintaining all tints and transparency levels of the original
• Expand the Duotone (to remove reference to a live Effect) and request the user to define a Drop Shadow
• Expand this again and rasterize maintaining the spot ink – ie. producing a multi-ink image
• Remove the temporary spot channel in the drop shadow image by the use of a Phantasm CS Swap Channels live Effect defined in the second Graphic Style (this was the clever bit to remove all trace of the original artwork in the shadow)
• Expand appearance one more and convert the shadow image to CMYK to ensure the result is not referred to as a multi-ink image
• Apply the cut-off curve using the Phantasm CS Curve Filter to what is now a simple CMYK image with no transparency
• Apply the Multiply transparency setting to ensure that the result appears to work like a drop shadow

Simple!

This article covers the specifics of handling spot color when simulating or compensating for flexo printing within Adobe Illustrator using Phantasm CS Studio or Publisher. It should be read in conjunction with the earlier articles in this mini-series.

General Curves and Levels control over spot inks

Spot colors are equally handled by Phantasm CS Studio and Publisher by the Curves and Levels tools. In each, it’s possible to control all spot inks used in the current selection via the Channel pull-down menu:

Notes:

• Changes to Curves or Levels in the default CMYK channel mode will make no effect on any spot colors within the selection. These have to be adjusted in their own Channel mode.
• It’s possible to adjust process CMYK and any spot channel in the selection simultaneously when the Curves and Levels tools are OK’d by individually adjusting the CMYK and then the spot channels curves/levels
• Photoshop’s Curves and Levels tools do not allow for control of CMYK and spot channels simultaneously. Therefore these tool’s settings files saved from Photoshop will only refer to CMYK channels. To maintain compatibility, Phantasm CS saves/loads Curves and Levels settings files individually for CMYK and each spot channel. If you wish repeat a combined CMYK and spot(s) adjustment, either re-open the Filter variant of the tool which recalls the last applied setting (in the same Illustrator session) or select Effect » Apply Curves/Levels. Alternatively, use the Actions or Graphic Styles systems.
• Spot control can be applied to flat-filled objects, multi-ink (“Device-N”) images, etc. The only special case is spot colored gradients, described next.

Spot colors within gradients

If a gradient is defined with spot color stops (you should never mix spot and process ink stops as a general best practice within Illustrator), the Accurate Gradient Adjustment option will be ineffective due to internal limitations. To overcome this, tick the Auto Rasterize option in the Phantasm CS color adjustment tools, ensuring that Preserve Spot Colors is ticked in Effect » Document Raster Effects Settings.

Another option is to use a small set of live Effects. This approach is non-destructive to the underlying gradient allowing for future changes which is harder to accomplish if an Accurate Gradient Adjustment is applied in a Curve adjustment resulting in many more gradient color stops.

1. Select one or more gradients filled with the same spot ink (they may each be different gradient profiles, but they can only contain tints of a single spot color).
2. Open the Effect variant of the Phantasm CS Swap Channels tool (Effect » Phantasm CS » Swap Channels).
3. Swap the spot ink entry to Process Black as shown below to change the gradient to a grayscale desaturated equivalent:

4. Apply the cut-off or compensation curve via the Effect variant of the Phantasm CS Curve tool’s CMYK channel as normal (the gradient is no longer a spot color).
5. Duplicate the Swap Channels entry in the Appearance panel (Window » Appearance, if not already open) by selecting the existing Swap Channels entry and clicking on the Duplicate Selected Item button on the bottom of the Appearance panel.
6. Drag this second Swap Channels entry below the Curves entry and then double-click on the lower Swap Channels entry to edit the live Effect.
7. In the Swap Channels window, select the original spot color as the target for the Process Black channel as shown below:

The results and the final live Effect stack in the Appearance panel can be seen below:

The upper gradient is the original constructed of a number of spot color stops of varying levels including below the 10% cut-off. The lower gradient is the result when the combination of Swap Channels and Curves live Effects are applied.

If you have Phantasm CS Studio or Publisher, you can examine the original file (ZIP compressed, for Illustrator CS3 and above) which may be downloaded by clicking here (173K).

Continuing the mini-series targeting the issue of ink drop-off in flexo printing using Adobe Illustrator, this article concentrates on specific object types and situations to watch out for. Once again, the ability to simulate or compensate for drop-off levels is possible directly in Illustrator exclusively with the use of Phantasm CS Studio and Publisher. However, note that we will also be adjusting some objects types such as drop shadows using tools only available in Phantasm CS Publisher.

Why detail the handling of specific object types? Well, Illustrator is a much more complex animal than Photoshop in terms of the number of different objects that may be created or placed within a document. Many of these various object types have an array of possible applications and uses. The most common objects which require special consideration and attention are to be found in this article.

Important: before you continue reading, it’s essential that you have read the first article in this series: Handling flexo printing ink drop-off in artwork using Illustrator.

Process CMYK gradients

Gradients are very commonly used and it’s easy to control cut-off levels for flexo ink drop-off with a few simple considerations. Let’s commence by creating a gradient in a CMYK document that starts with CMYK white and ends with a red shade using each of the 4 process inks:

Keeping this gradient selected, open the Phantasm CS Curves Filter tool via Filter » Phantasm CS » Curves in Illustrator CS3 or below or Object » Filters » Phantasm CS » Curves in Illustrator CS4 or above. It is critical that, when applying a flexo cut-off curve to a gradient that the Accurate Gradient Adjustment option is ticked. To access this option, you need to view the advanced options via the Curve tool’s pull-down menu shown below:

At the bottom of the extended option area, the option presents itself with an associated slider control:

By ticking the option and increasing the Max Stops level to the upper limit value of 100, Phantasm CS will ensure that additional stops are intelligently added to the gradient to produce the desired result. Without these additional color stops in the gradient, the color cut-off levels described in the previous article would have no apparent affect. For more information on how this Phantasm CS option works, please refer to the user manual.

WIth a 10% cut-off applied the gradient is adjusted as shown below (original on top, adjusted beneath with automatically-updated color stops shown in the Gradient panel beneath):

It can be noticed that the cut-off transitions are slightly blurred. This is due to the minimum distance the gradient’s color stops can be placed next to each other. Even though the neighbouring color stops have stepped color changes, the gradient still blends between these which produces what appears to be a blurred boundary. In reality, these would not cause a problem with simulating flexo ink drop-off within Illustrator, and wouldn’t feature if the compensation approach is taken described in the previous article. However, it a more abrupt cut-off is essential in a gradient adjusted for flexo, then it’s possible to opt for the Auto Rasterize option found in Phantasm CS’ color tools. This overrides the Accurate Gradient Adjustment controls and first rasterizes the selected object(s) before committing a color adjustment. The rasterization is based on the settings defined in Effect » Document Raster Effects Settings…, so it’s important to ensure the correct resolution is first set along with other options present!

To demonstrate the difference between using the Accurate Gradient Adjustment option and Auto Rasterize, the two gradients adove were adjusted using the different options. The top gradient uses Accurate Gradient Adjustment whilst the lower uses Auto Rasterize.

For control of spot color gradients, please refer to the special Spot color article’s sub-section.

Linked artwork

Linked artwork, typically image files, can not be controlled by Phantasm CS. By their nature, linked external files are controlled outside the Illustrator document as they may be applied in other documents and any change made to them would affect all associated documents.

To simulate or compensate for flexo ink drop-off in Illustrator, first embed the linked files. Embedded images can always be extracted from the document using Phantasm CS Studio and Publisher Edit Image tool (discussed in this article), or Phantasm CS Publisher’s Link Images tool.

Transparencies

Transparencies of all types applied to an object, or an overlaid object, can upset any carefully-defined flexo cut-off Curve. Therefore its is usually essential to first flatten any transparency before cut-off curves are considered. This can be achieved using the Object » Flatten Transparency… tool.

Transparency types to be aware of:

• Native transparency modes typically applied via the Transparency panel
• Opacity Masks created using the Transparency panel
• Images with alpha channels
• Transparencies integral to certain live Effects including Gaussian Blur but excluding Drop Shadows and Glows which are dealt with separately in the following section
• Transparency levels within Gradients (Illustrator CS4 and above) and Gradient Meshes (Illustrator CS5)

Note that a vector clipping mask is not a transparency and doesn’t require expanding.

Drop Shadow and Glow live Effects (best practices)

Some of the most widely used live Effects include Drop Shadows and Inner/Outer Glows. It’s important to understand how these are constructed by Illustrator internally in order to understand best practices to adjust for ink drop-off.

Let’s take the example of applying a purple (100% Cyan + 100% Magenta) drop shadow to the letter “A”…

The process Illustrator takes is as follows:

1. The object onto which the shadow will be applied (1) is duplicated, the duplicate is then rasterized as a grayscale image, inverted in color and blurred (2)
2. A rectangle of solid color defined by the user in the Drop Shadow window (in this case purple) is drawn to match the size of the blurred duplicate (3)
3. The blurred duplicate and the solid color rectangle is combined as an Opacity Mask where the black area of the raster mask equates to 100% transparent areas
4. This opacity mask then has the optional transparency type and transparency level determined in the Drop Shadow window applied and placed beneath the original object (4) to complete the effect

It’s important to note that the shadow effect is not made of varying levels of color. The solid color rectangle combined with the opacity mask defines the fading levels of color for the shadow. This same principle also applies to Inner and Outer Glows – the only real differences being a lack of offset.

With this knowledge, it becomes logical to state that a color curve cut-off will not have the desired effect on a drop shadow or glow live Effect due to the transparency being the key factor. Of course, it’s possible to flatten the effect and transparency but this does negate any future changes. And as it’s such a common set of effects, there is a better way with Phantasm CS Publisher.

One of the tools introduced in the top-level of the Phantasm CS range was the ability for the live Effect variants of the Curves and Levels tools to control the bitmap alpha channel of any image – including those found in other underlying live Effects. Therefore, to apply a cut-off level to the previous drop shadow example, select the object with the drop shadow or glow and open Effect » Phantasm CS » Curves and select Bitmap Alpha from the Channel drop-down menu as shown below:

Note: as we are dealing with the mask of the thing we want to affect, the curve is rotated through 180°. Therefore the cut-off or compensation is applied to the top-right of the curve, not the lower left. However, it’s possible to flip the graph temporarily by clicking on the left/right double arrow button highlighted in the tint scale bar beneath the graph.

The image, above, also shows the live Effect curve has an arbitrary 10% cut-off level applied – where the shadow ends more abruptly.

Important: This method dictates the following best practices:

• Define a drop shadow color using only 100% tint of any ink (either a combination of CMYK or a spot color)
• The transparency defined in Drop Shadow or Inner/Outer Glow must be set to Darken or Multiply
• The opacity level defined in Drop Shadow or Inner/Outer Glow must be 100% (the final transparency level and profile can be adjusted with the Bitmap Alpha curve)

If, say, a color of 30% Cyan, 50% Magenta, 45% Yellow and 20% Black was used as the shadow or glow’s color, the curve applied to the Bitmap Alpha channel would affect this only proportionately. If a 10% Bitmap Alpha cut-off was applied to the afore-mentioned process CMYK color, then each ink would result in cut-offs of 3%, 5%, 4.5% and 2% and not the intended 10% for each channel.

It’s understood that apart from common pure black and spot color shadows and glows, that these best practices would impose too-great-a design restriction on most users. Therefore Astute Graphics has devised a series of instantly applicable Action sets which work around these limitations and allow operators to produce variable tint process CMYK shadows and glows with correct cut-off levels in a matter of seconds. This is covered in the dedicated article: Applying flexo cut-off curves to CMYK shadows and glows.

Other applied live Effects

This refers to any life Effects, especially other Phantasm CS color adjustments which may be applied on top of artwork being modified for ink drop-off simulation or compensation. If, for example, an embedded photo has a cut-off curve applied as a Filter, but that image also has a Bightness/Contrast live Effect applied, the curve will change the underlying image, but the live Effect will then update to adjust it once more. Depending on the settings being applied, the Brightness/Contrast adjustment could cause areas of the image to dip below the minimum threshold applied by the Filter.

It’s therefore advised that if a permanent flexo ink drop-off simulation or compensation curve has to be applied via the Phantasm CS Filter, that all effects are first expanded first via Object » Expand Appearance.

If you wish to maintain the live Effect to allow for future editing, the cut-off curve has to be applied as a live Effect and ensured that it remains at the bottom of the effects stack found in the Appearance panel.

Non-destructive flexo cut-off curves

If a cut-off curve which simulates or compensates for flexo ink drop-off is applied to artwork as a Filter, it is destructive. This means that the original artwork has been permanently adjusted and if the artwork is loaded in the future, it’s impossible to revert to original state without a secondary copy to call upon.

However, if the curves are applied as live Effects, the underlying artwork remains unaffected and the curve may be removed via the Appearance panel at any point in the design (unless the appearance is expanded). This has major obvious benefits, but it’s important to consider one side-effect; when measuring colors within Illustrator or through Phantasm CS’ edit embedded image tools and Photoshop, you will be measuring the original color levels and not the result following the live Effect.

In order to measure the result of a live Effect cut-off curve having been applied, temporarily expand the appearance (Object » Expand Appearance), make the measurement, and then Undo expansion to revert back to the live Effect.

Repeating common cut-off curves

Phantasm CS and Illustrator combined allow for several methods to quickly access common cut-off curves to either simulate or compensate for flexo ink drop-off:

1. Curves settings files: the Curves (and Levels) tools allow settings files to be saved and loaded. These settings files are compatible with Photoshop to ensure that changes made within Photoshop can be reflected in Illustrator.
2. Filter variants of the Phantasm CS tools can be incorporated into an Illustrator Action for quick replay. This technique is also covered in the dedicated article Applying flexo cut-off curves to CMYK shadows and glows, where it will used to apply correct adjustments to mixed tint process CMYK shadows and glows. [Also see Adobe Illustrator user manual reference for Actions]
3. Curves applied as live Effects can be turned into a Graphic Style which can be saved into the Graphic Style Library for future quick reference. [See Adobe Illustrator user manual reference for Graphic Styles Library]

This article commences a new mini-series targeting the issue of ink drop-off in flexo printing and how to handle this whilst operating within Adobe Illustrator using Phantasm CS Studio and Publisher. It’s intended for all designers and operators of Illustrator in the packaging and flexo print industry as well as designers who may be required to produce packaging artwork.

If you want an introduction into flexo – or “flexographic” – printing, it’s suggested you refer to this Wikipedia entry and the introduction video produced by the industry promotion group Flexo4All. Flexo printing is used widely in the packaging industry where printing is possible on many substrates including plastics.

In this introduction article, we’ll cover the basics of ink drop-off and how to adjust an embedded image to either simulate the issue or compensate for it. Following articles will concentrate on the specific requirements to control drop-off levels within Illustrator on objects such as drop shadows and gradients, and attributes including transparency.

What is “ink drop-off”

The issue of ink drop-off, also referred to as “cut off levels” and “minimum dot size”, is determined by the method in which flexo prints are produced. Rather than the printing plates for each ink separation commonly used in offset/lithographic printing, flexo printing typically relies on photopolymer printing plates which are, as their name implies, flexible.

It is thoroughly recommended that you read the explanation published by FlexoGlobal entitled Minimum Dot for Photopolymer Flexo Defined. This covers the mechanics of the situations as well as touching on solutions possible in Photoshop. These industry-accepted solutions form the basis of the methods due to be applied here, except with a more detailed overview of Illustrator artwork specifics.

An excellent example of the problems that can result from ink drop-off levels is shown above (image source: FlexoGlobal, reproduced with kind permission). This scan of artwork produced using the flexo print method clearly shows an unwanted and distracting black hard edge in the right-hand area of the sky. It is due to the fact that the smallest black separation ink dots required for the first few percent of black channel tints physically could not be reproduced.

To see what’s happening more clearly, the above gradients – one grayscale and one process CMYK, each have a 10% cut-off level applied. This is higher than the levels experienced on flexo printing (typically between 1 and 3%), but does show how the eye quickly notices the abrupt end to a continuous change in tone. Each numbered cut-off stage is detailed as follows:

1. Grayscale gradient first appears at 10% tint
2. Yellow cut-off in process gradient
3. Cyan cut-off in process gradient
4. Magenta cut-off in process gradient
5. Black cut-off in process gradient

Notice how the process gradient’s inks all end at different stages when a uniform 10% cut-off is applied. This is because each of the CMYK inks start at different levels and all blend towards the left-hand edge where each ink dwindles to zero.

Showing ink drop-off in Illustrator

This uses exactly the same methods as would be employed in Photoshop, except that with the use of the Curves tool in Phantasm CS, the drop-off levels may be applied to both embedded vector (shapes, text, gradient fills, etc.) and raster (TIFF, JPEG, etc.) object types simultaneously.

As an example, the following image is placed and embedded into a CMYK Illustrator document:

The separations for this original image can be seen as follows:

First open the Curves Filter tool (we want to make a permanent change in this example) via Filter » Phantasm CS » Curves in Illustrator CS3 or below or Object » Filters » Phantasm CS » Curves in Illustrator CS4 or above:

The Curves graph is available in two sizes; small and large. By default the graph is small and should be toggled to the larger size by clicking on the lower right button (1) to allow for greater accuracy when defining cut-off levels that will equate to the ink drop-off in flexo. Once enlarged, opt for the “pencil” curve editing mode (2). Then carefully draw a horizontal line (3) at the bottom left of the graph area ensuring that the line starts at an Input value of 0% and ends at 10% whilst maintaining a constant Output value of 0%.

Before applying this, it’s possible to save this graph (or a more relevant cut-off value of 0-2% or 0-3%, etc.) by clicking on the Save… button. This will allow you to save the graph as a Photoshop-compatible .amp settings file. Alternatively, if you already have a series of cut-off settings originally created in Photoshop correct for a specific flexo setup, you could import and use these via the Load… button.

Upon applying this 10% cut-off level, the following result may be seen:

The highlighted areas show the areas of maximum visual damage due to the ink drop-off. In the case of the right-hand highlight, it’s the cyan separation which abruptly cuts out. Refer to the original separations, above, where it may be seen that the cyan channel hovers around the 10% tint level just where the problem occurs. The left-hand highlight shows all three CMY separations being cut-off in the shadow which is a common problem.

Whereas simulating this drop-off effect in Illustrator using Phantasm CS’ tools doesn’t cure the problem, it does, in combination with the array of color control tools on offer in Phantasm CS, allow a designer or operator to work around this issue. (Remember that the cut-off level is more likely to be a couple of percent and not 10% as shown previously.) For example, in the image above, it’s possible to boost the cyan channel so that it doesn’t near the cut-off level, although this may have to be compensated for with the other channels to ensure the end result isn’t badly tinted. This is where the skill and experience of the designer or operator comes into play…

Compensating for the drop-off level

An accepted method of ensuring no point in the artwork goes below a cut-off level causing flexo printing ink drop-off, is to use the Curves tool to adjust the image so that the white point moves up to the cut-off level. By example, we’ll return to the previous original image (before the cut-off curve was applied) and re-open the Phantasm CS Curves Filter window:

Note: if the old cut-off setting remains from the previous application of a Curve Filter, first revert to the curve editing more (1), hold down the Alt key and notice that the Cancel button temporarily becomes Reset. Click on this button whilst in the Reset state.

To make the compensation “curve”, click on the bottom left curve node to select it (it changes from a hollow filled node to a solid fill) and enter a value of 10 in the Output box. It’s important to note that the node was not dragged as Input/Output values are rounded up/down and manually dragging the node would be less precise meaning you could be applying a 9.6% cut-off instead of 10%. This matters more when a realistic cut-off level is nearer to 1%.

Applying this will result in a darker image (less noticeable if the image is compensated for only by a more realistic 2%). It’s possible to verify the resultant adjusted image in Photoshop using Phantasm CS Studio and Publisher’s Edit Embedded Image tool (Edit » Edit Image):

With the CMYK image in Photoshop, the Info panel (1) is opened, if not already so via Window » Info. The sample mode is set to 32-bit (0.0-1.0) by clicking on the tiny pipette menu pull-down icon (2) for added accuracy (the right-hand information (4) remains at 8-bit (0-255) for clarity).

By passing the pointer over the areas of concern (3), the Info panel confirms that no channel goes below a 10% tint (4). Therefore this image would no incur any ink drop-out on a flexo print press. Note that the left-hand shadow doesn’t feature drop-out issues either.

References

Before we continue this mini series, it may be useful to refer to the following useful resources on flexo printing:

• Flexoglobal.com: a great resource of news for the flexo industry
• Flexo Exchange: another great site dedicated to flexo printing, including an active forum
• Ugly Flexo: an extensive range of videos, mainly geared towards print operators, but with some interesting insights for designers also
• Artwork Guide by Systems Labelling: a useful PDF introducing flexo print considerations for designers – read this if you design for the packaging industry
• Flexographic Technical Association: industry body website
• Flexo4All: industry alliance to promote flexo printing
• Glossary of flexo terms: useful Word (.doc) file with a very extensive reference of terms for the industry

Kiwi fruit example image courtesy of Fotolia, supplied freely with Computer Arts issue 130.

This article is published as part of the exclusive AG blog series Avoiding 10 Illustrator Publishing Pitfalls

The last tip in this series – which we hope you’ve enjoyed and found of use – simply contains two main points (you’ve read enough, we’re sure!)…

Get a proof printed

There are many wonderful soft (ie. on-screen) proofing systems out there. Astute Graphics adds to Illustrator’s native Overprint Preview mode with its output preview systems. Esko, likewise, produces its DeskPack range of Illustrator plugins which are high-end tools for high-end users. And then there are external proofing systems starting at Adobe’s own Acrobat Pro, and upwards. All these packages serve a purpose and truly save time and money. However, for many designers and publishers, there is simply no better way to find problems before artwork is sent to the press than producing a physical printed proof. If set up correct (and your local print provider should offer a full proofing service), there is less argument of color and layout. WYSIWYG is an old phrase – but really holds true when held in the hand!

Get the proof signed-off

Once proofed and you’ve ironed out all the errors you can find, get the final printed proof signed for approval by your boss or the person who’s paying the job. It’s amazing how a person will check a printed proof awaiting their signature more thoroughly than a simply tick-box on-screen or a casual “yes – that will do” remark. Then there’s no argument… or if there is, there a better chance that you’ll be vindicated.

Series conclusion

This series has been quite a journey through some of the less talked-about aspects of publishing pitfalls and potential solutions for Adobe Illustrator. In researching the articles, we’ve learnt a couple of new things along the way. If you have any additional tips, comments or corrections, please post a response at the end of the relevant articles and we’ll be sure to look.

Tell your friends, colleagues (and the world!) about this series. If it proves popular we hope to follow it up with more in-depth advise and tips.