Flattening Transparency Properly When Using Layer Appearances in Adobe Illustrator


For longer than I can remember, I have been flustered with the Flatten Transparency feature in Adobe Illustrator CS3 and CS4. Very often I use the excellent Layer Targeting feature introduced into recent versions of Adobe Illustrator, however I found that when using the Flatten Transparency feature, it seemed to ignore the attributes of the Targeting, which forced me to find lengthy workarounds to solve this. Turns out there was an approach to solving this that I had overlooked…

Typically I use Layer Targeting in order to add a shading layer to my illustrations. I do this by creating a new Layer, then Targeting that Layer, and then adding a Layer Appearance effect—in this case I am changing the layer’s Blend Mode to Multiply with a 40% opacity setting. This allows me to just use flat color on this shading layer, and because of the targeting, any objects placed on this Layer inherit the effects applied when I set up the Targeting.

Here was the snag: when exporting final files for clients, I usually provide the vector art as a version 8 Illustrator EPS file, as this removes all special Illustrator-specific features I used in creating the artwork, resulting in a file that is just about as compatible as it can possibly be with not only earlier versions of Adobe Illustrator, but also other vector graphics software. “Dumbing down” the file like this ensures that clients will not run into issues of needing to have the same version of Illustrator I use, especially since I keep up to date on the current versions and realize not everybody else is as quick to upgrade as I am.

Typically when running the Flatten Transparency feature, all one needs to do is select all the items which are affected by the transparency and run Flatten Transparency (typically I just select all the artwork to do this). However, I found in Illustrator CS3 and CS4 that all my targeted (shading) layers were defaulting to flat areas of solid, opaque black. this was not the result I wanted. I went so far as to submit a bug report to Adobe on this, with no reply.

Frustrated, I posted to Twitter about this. Illustrator guru Mordy Golding is one of my followers, and he picked up on my complaint. At first he was in agreement that I had found a bug. However we began to “tweet” back and forth, and by doing so Mordy stumbled on to the solution: not only does one need to select all the artwork, but additionally one needs to also “target” the layers with targeted effects applied. Bingo!

We discussed briefly after confirm this solution that indeed this makes sense, as the Flatten Transparency feature only works on items that are selected, and indeed the Targeting feature is a form of selecting items, although not very obvious or intuitive at first.

If you refer to the image on this post, you’ll see I have highlighted the Layer Target circles. You can determine visually if a layer has been targeted and effects applied of the circle is filled in with dark gray.

Contributors to iStockPhoto might find this especially useful, as iStock requires all art to be flattened and submitted as version 8 Illustrator .eps files.

3 thoughts on “Flattening Transparency Properly When Using Layer Appearances in Adobe Illustrator

  1. What does the flatten transparency really do? I have never used it, and have never had a need to, but am interested in learning about it.

  2. Good question, I probably should have addressed this in the post. I usually export my vector art for clients as version 8 Illustrator EPS files for maximum compatibility with other software (or older versions of Adobe Illustrator) that can handle EPS format but not all the fancy features in the CS versions.

    Also, many stock illustration sites require one to submit in version 8 EPS format for the compatibility mentioned above.

    This allows Corel users and probably many other vector art software packages to open these files. The transparency and other effects one can use in Adobe Illustrator will not render properly if saved as version 9 or any of the CS versions and the file is opened in an earlier version of Illustrator or another graphics program.

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