Today's questions from Jacob Brunny deal with the topic of transparency. If you haven't already seen my Adobe online eSeminar on the topic of transparency, you can check it out for free here.
We got a proof back from the printer today that had some objects that were vector but looked like they were rasterized. After watching your e-seminar yesterday (which was great) I looked at the transparency flattener and sure enough, we had been using EPS set at a medium resolution and those problem areas were the ones that illustrator was making rasterized complex regions. So my question is this: Once you have that EPS file set at a medium resolution, what can you do to undo that damage. I tried taking that EPS and saving it as an EPS with a high quality preset but those problem areas are still showing up. I also tried saving as native AI but it was still showing up. So can that damage be undone by saving as AI and then a PDF? Also can a printer override those settings? Can InDesign override those settings if you place a medium quality EPS into it? Also was there a place in Illustrator or InDesign where you can set the transparency level for all documents?
Jacob then followed up his original question with this:
So if you save a native AI file as a PDF/X-1a PDF does that ensure if will print correctly even on laser-jet/ink-jet printers if they don't have the overprint preview box checked in Acrobat? I am sending in an ad to a magazine but I have no clue how they will be printing it (it is a two color job using black and one spot color) I saved it as a PDF/X-1a PDF and when I viewed it, it looked off, so I referred to a post on your blog about setting the overprint preview in Acrobat and that worked but I wanted to know how that will affect the ad if the magazine doesn't have that option selected when they go to print it?
Not that I was counting or anything, but I think that was six questions Jacob :)
But they are actually great questions, and hopefully the answers will help many others looking for the same information.
Let's start from the beginning. The file was saved as EPS, and after you realized that some rasterization was occuring, you checked and found out that the file was saved using the Medium Resolution flattener setting. And the kind of rasterization that you seem to be referring to here is that of rasterized complex regions (that's when Illustrator rasterized parts of your file not because it can't preserve them as vectors, but because it wants to print the file faster). And you know from watching my eSeminar, that using the High Resolution flattener setting will disable Illustrator's ability to rasterize for performance reasons.
Well, the truth is, you can simply reopen the EPS file in Illustrator, and resave the EPS using the High Resolution flattener setting. You can do this because when Illustrator saved the EPS, it also snuck in a full native CS2 version of the file which is in an unflattened state. So you'll always be able to reopen the EPS to resave it using a different flattener preset -- well, actually, not always. Because there's one situation where saving to EPS will be irreversible. When? When you save your file as an Illustrator 8 compatible EPS. Why? Because Illustrator 8 didn't support transparency. So even though Illustrator sneaks in a native file that allows you to reopen the file, the native version is useless because it's flattened as well. So while I'm not sure what the circumstance is with your file, if it was saved as an AI8 EPS, then if it was saved using the Medium Resolution flattener setting, it stays that way... for life.
As a note, if the file was saved out of Illustrator as an EPS, then a printer can (if he knows to do this) reopen the file in Illustrator and resave it with the right flattener settings. Unless of course, you saved it as an AI8 EPS, in which case, you've shot yourself in the foot, and your printer can offer nothing to stop the bleeding (or the pain for that matter).
As for InDesign, once you place an EPS into InDesign, that EPS is already in a flattened state. Therefore, InDesign cannot change the flattener settings. As a user, you would need to reopen the EPS manually in Illustrator, and resave it with the proper settings (keeping in mind the AI8 issue mentioned above). This is why placing a native AI file (which is a PDF 1.4 file) into InDesign is key. Because then, InDesign DOES control the flattening of the file.
I don't believe there's a way to set all documents to use a specific Flattener setting automatically. Although once you do specify a setting for a document, it will stay with that setting. A solution might be to set up a template that uses the High resolution setting, and to always start new documents from that template.
With regards to your last question, when you use spot colors and transparency, the flattener often uses overprint commands to preserve the spot colors. So as you pointed out, you need to use the Simulate Overprints options when printing, or to use the Overprint Preview mode to see the results in a proof. But that is for proofing only. When the file is actually separated to plates, the file will print correctly. Simulating overprints is something that is only applicable when viewing a composite of the document. So from what you describe, you should be ok.
I hope this answers your questions Jacob, and I hope that it also answers the questions of those who were too shy (or too busy) to ask them as well.