Working with PostScript (EPS) files
Video: Working with PostScript (EPS) filesWhen it comes time to saving your Illustrator files for placing into other applications. For example, maybe you're taking your file and you're placing it into InDesign or you're placing it into Microsoft Word or to QuarkXPress, so on and so forth, you have to pay attention to the file formats that you're using. Now if you're going into InDesign, it's something we'll actually cover in detail in the next movie, but the best file format that you could use is to actually stick with the native Illustrator file format. However, if you're sending graphics into QuarkXPress or into other applications that maybe are unknown to you, for example, a client requests a image from you or some piece of artwork from you and you don't really know how they're going to be using it, the best way to provide it to them is in a standardized format called EPS or PostScript.
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In this installment of Illustrator Insider Training, Mordy Golding shows experienced Illustrator users how to create transparency effects and ensure reliable printing results. This course reviews the history of vector transparency and covers features such as knockout groups, opacity masks, and transparency flattening. Mordy also shows how to establish a safe workflow when placing Illustrator graphics containing transparency in PostScript, PDF, and InDesign files. A free worksheet is included with the course.
- Understanding how transparency works across the Adobe applications
- Deconstructing the Transparency panel
- Adding transparency to gradients
- Understanding how overprints and knockouts work
- Using a gradient or complex appearance as an opacity mask
- The rules of transparency flattening
- Working with complex regions
- Understanding the relationship between flattening and stacking order
- Creating and sharing flattener presets
- Saving PDF files and using the PDF/X standards
Working with PostScript (EPS) files
When it comes time to saving your Illustrator files for placing into other applications. For example, maybe you're taking your file and you're placing it into InDesign or you're placing it into Microsoft Word or to QuarkXPress, so on and so forth, you have to pay attention to the file formats that you're using. Now if you're going into InDesign, it's something we'll actually cover in detail in the next movie, but the best file format that you could use is to actually stick with the native Illustrator file format. However, if you're sending graphics into QuarkXPress or into other applications that maybe are unknown to you, for example, a client requests a image from you or some piece of artwork from you and you don't really know how they're going to be using it, the best way to provide it to them is in a standardized format called EPS or PostScript.
However, as we've already discussed throughout this entire title, PostScript is a language that does not understand transparency. In other words, when you save your file as an EPS file out of Illustrator, the information in that file is going to be flattened information. Now let's understand why that is significant to keep in mind. If I take a file out of Illustrator and it has no transparency whatsoever and I save it as a PostScript file, I can now scale that up in size when I place it into another application. I can make it as big as I want and I will not have any loss in quality whatsoever.
After all, I'm simply scaling up the vectors in size. However, if because of the flattening process, my file actually now has some areas that have become rasterized, then those rasterized areas are of a specific resolution. And therefore I can't just assume that I can now scale that EPS file to any arbitrary size. Take this file for example. It's called label.ai and I have a soft shadow that I've applied to some artwork here. That soft shadow in the flattening process is going to result in some parts of my file becoming rasterized.
Now even if I use the High Resolution flattener preset out of Illustrator, that only rasterizes content at a specific resolution. So it'll print fine if I keep this artwork at actual size, but if I now decide to place this for example into Quark and scale it up 1000%, I'm going to start to see pixels in the rasterized areas of my document. So the first thing to note about working with Illustrator is that if I know there's transparency in my file-- and remember I can use the Flattener Preview panel to see that-- I should probably make sure that my artwork is actually scaled directly here inside of Illustrator to be actual size.
Remember that since I'm inside of Illustrator here, my flattening has not occurred yet. I could scale it up infinitely in size here inside of Illustrator. The only problem is when I start going out of Illustrator, when I save it as an EPS file, at that point it's going to be flattened. So I just want to make sure that if I know this is going to Quark and it's going to have to be enlarged at a large size, I might choose to enlarge it here inside of Illustrator first before I save my EPS file. Next, when I actually save my EPS file, I want to make sure that Illustrator is using the correct flattener settings.
So that I can be assured that my file will print correctly. Let's see how to do that. I'm going to go to the File menu here, I'm going to choose Save As, and in the File Format here, instead of choosing Illustrator I'm going to choose Illustrator EPS. I'm going to click Save. And now we can look over here where it says transparency, I can now choose one of my transparency flattener presets. Now some people don't pay attention to this and they just use the default setting, which is the Medium Resolution setting. But understand what that means. That means if I now give this EPS file off to a printer or off to somebody else, and they place it into a different application, even if they now use that other application to crank up their flattener settings to be the greatest possible thing ever, it will not have any effect whatsoever on this file, because this file has already been flattened.
Let's talk about InDesign for a second. We know that InDesign has the ability to preserve transparency, but that's only if I send the transparent file to InDesign, meaning I save a native Illustrator file to InDesign. But if I save an EPS file out of Illustrator and I save that EPS file with a Medium Resolution setting and then I place it into InDesign, InDesign at that point just sees a flattened file and it's already been flattened at the Medium Resolution setting. So even if I now choose to print with a Higher Resolution preset out of InDesign, it's too late. My original Illustrator file has already been tainted somehow.
It already has the bad flattener setting inside of it. So when we are using EPS, we want to make sure that we're going to be using the right settings. If I have to use an EPS file, I'm going to come here to where it says Transparency and I'm going to make sure that I'm using the High Resolution preset, because again that assures me that I'm able to get the highest possible quality when outputting this file. Now if you save an EPS file and this entire Transparency section is completely grayed out, that's another indicator to you that this file does not contain any transparency inside of it.
In other words, if you can't select this, if this area is grayed out, that means that your file does not have any transparency, so there's nothing to worry about. I will point out one of the thing also which is that you have the ability inside of Illustrator to back-save your files to older versions of Illustrator. Now transparency was introduced in Illustrator 9. However, Illustrator 8 has no transparency features whatsoever, so even if I were to have reopened that file backup inside of Illustrator 8, I would have a completely flattened file. In fact, let's take a moment to talk about reopening files back inside of Illustrator.
Now let's say I go ahead now and I take my Illustrator CS5 EPS file. I save it with my High Resolution preset and I click OK and now it gets saved to my Desktop. In fact, let's do that right now. I'm going to choose to save as EPS file, I use that High Resolution preset, and now I'm going to close this file, choose File > Open, go to Chapter 5 here where I've saved that EPS file, click on it to open it up now back inside of Illustrator. Now remember when I saved the EPS file, it was completely flattened, right? All the information in there was flattened. So that would mean that if I now come back into Illustrator here, I should see all these areas broken up and turned into those atomic regions, right? But if I click on this object right now, I see that I still have that live drop shadow here in my Appearance panel.
In other words, my file doesn't seem to be flattened at all. So what's going on here? If I save my EPS, it must go through that flattening process, but if I reopen the EPS back inside of Illustrator, I see that it hasn't been flattened at all. The answer to this is that when you save a file out of Illustrator and you save it as an EPS file, Illustrator figures you may want to reopen that file back in Illustrator at some point in the future. And when you reopen that file, you don't want to lose any of the editability of your file. So what Illustrator does when you save an EPS file is it actually puts two versions of your file inside of that EPS file.
So when I choose to save my file as an EPS file, Illustrator saves a flattened version in the EPS portion of the file, but it also sneaks in a full native version of that Illustrator file. And when I reopen that EPS back inside of Illustrator, it completely discards the flattened EPS part of the file and reads its own native version, which still contains the live transparency. That assures that I'm always able to edit my EPS file back in Illustrator, but if I ever replace that EPS file into other applications, they see and process the flattened information.
So if you need to work inside of an EPS workflow, just keep these things in mind.
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