Resolution Confusion: Is There a Solution?

285ppi divided by the line screen, carry the one -- oh! Hi there! Sorry, you caught me trying to figure out the correct resolution I needed for my file. Resolution you say? Surely Mordy, you must be smoking something good, because we know that vectors are resolution independent and are output at the resolution of the output device. Right?

Well... kinda.

You see, in today's modern world, pixels and vectors live in harmony -- all within Illustrator. And with all the snazzy effects that designers want to use (don't make me say it -- you know which particular effect I'm referring to), one would be foolish to overlook the fact Illustrator artwork today contains many raster-based effects (sometimes even without our knowledge).

The reason why I bring this up is because it requires a change in thought, which is something that doesn't happen easily due to human nature (see, taking that Psychology class I took in college came in handy after all). After all, if you're in Photoshop, you're mind is always on the issue of resolution. Heck, you can't even create a new Photoshop document without first defining a resolution. On the flip side however, those of us who have been using Illustrator for many years have never even thought about resolution. And surely, you wouldn't think to set the resolution of your file in Illustrator when you first create it? Would you? After reading this, you might ask yourself that question again.

Great, so you have come to realization that maybe there is a resolution setting in Illustrator after all. But come on now, do you really think the folks at Adobe would make things so easy for you? Illustrator doesn't have a single resolution control setting -- it has THREE of them. Yeah, grab a beverage, pull up a chair and get comfy -- this one's gonna be a while...

OBJECT RESOLUTION - Actually, this is what it *used* to be called, before Illustrator CS rolled around. Now it's called "Flatness" and can be found in the Paths section of the Graphics panel in the Print dialog box. Back in the old days, you were able to set the object resolution for a file (in the Document Setup dialog), which controlled how smooth a curved line would appear when RIP'ed. In today's "new and improved" Illustrator, this setting has become obsolete and the Flatness, by default, is automatically optimized for your output device. I mention it here, however, because there have been times when I've seen that some legacy files have caused issues with this setting. Jean Claude can tell you of a certain bug that set the Object Resolution to 100 at times, making for files that were not acceptable after printing. If you're using Illustrator CS2 exclusively, then you're in the clear (as far as I know) and don't have to stay up nights worrying about this setting.

FLATTENER RESOLUTION - I love transparency. I really do. I can't imagine living without it. And if you're like me, you know that the flattening process, which must occur in order to properly print transparency effects to a PostScript device, may cause vector objects in your file to become raster. In fact, let me clarify that even more by stating that PARTS of vector objects may even become raster in your final output. Well, if parts of your file are now raster, who determines that resolution those rasters are created at? You do. If you know about your flattener presets, you know you can choose from one of Illustrator's 3 low, medium, and high resolution settings. You may even know that you can create your own presets and set the resolution to whatever value you feel will allow you to sleep at night.

Yet, if you've applied those snazzy effects (did you know that Ted Alspach and I once joked about setting a daily limit on the number of drop shadows you would be able to apply? You'd get a dialog box that said something like "you'd reached your allocated number of drop shadows for today, please try again tomorrow"), you might think that setting your Flattener Preset to the High Resolution setting will get you the results you expect. And sadly, I'm here to tell you that you'd be mistaken. For there's a third resolution setting in Illustrator, and it's probably the most important of all...

DOCUMENT RASTER EFFECTS SETTINGS - You'll find this setting in the Effect menu. This setting controls the resolution that's used for all Effects that are raster-based. This includes Drop Shadow, Feather, Inner Glow, Outer Glow, 3D (when raster or gradient content is mapped to a surface), and anything below the divider line, marked in CS2 as "Photoshop Effects". What makes life "fun" is that the default for this particular setting is 72ppi. If you're a print designer, this setting is blasphemous and is grounds for divorce from Adobe. After all, the only reason why Adobe made the default setting at 72 ppi was to make all of the web designers of the world happy. Well, that's simply isn't true, but it still leaves the print world wanting more. The true reason why the default setting is 72 ppi is because of performance. Go ahead, crank up the Document Raster Effects Settings to 300 ppi. Then apply a Gaussian Blur.

That's ok, I'll wait...

Still waiting....

La la la deee dooo da -- oh, are you back yet? You must have one of those fancy shmancy G5 computers.

Seriously though, the higher the resolution, the slower the performance. Mind you, the performance lags when doing "simple" tasks, like scaling, scrolling, zooming, even just moving objects. And if you have to undo something, that might be a good time to refill that beverage...

OK, so you know that if you're a print designer, you have to set your Document Raster Effects Setting to something higher, and that you're going to have to put up with slower performance. Not much of a choice there. Or is there? I mean, couldn't you dial in a low resolution during the proofing process and change it to high res just before you print? The good news is, you can! But there's a catch. It depends WHICH effects it is that you've used in your file.

You see, the Effects menu is split into two sections: Illustrator effects, and Photoshop effects. Illustrator effects are resolution independent in that you can change the resolution at any time and the effect will look the same. Illustrator does the math for you under the hood and gives you a result you expect. However, when you use Photoshop Effects, those are resolution dependent and such effects look very different depending on what the resolution setting is. For example, the Mezzotint filter offers a very different appears when the resolution is set to 72 ppi than it does with the resolution set to 300 ppi. So you can't just change the resolution right before you print your file, because the apeparance of the effects may change dramatically. (This is why the Print dialog box smartly informs you what the Document Raster Effects Setting is set to, but it doesn't allow you to change it -- as doing so may change the appearance of your file without you knowing it. For this reason alone, if you work in print, it's best to set that resolution setting to 300 ppi at the outset of your design process.

The truth is, there's plenty more to talk about on this topic, but I have to go out and shovel some of that record-breaking snow we just had.