Expert: Amy - 4/27/2008

Question
Amy,
I use Illustrator to make small mathematical figures to put into papers online, the pictures need to be PDF, JPEG, or PNG, and need to be of the smallest file size possible without compromising quality much.

So far I have had the best luck with PDF and PNG:

(In CS1) For PDF, I put my image on a new blank page, then crop to the size of the picture (1.5 in by 0.5 in, for example), then "save as" PDF, using jpeg compression with "minimum" quality, and I get a file of excellent quality that is 24 KB.

(In CS1) For PNG, again I put my figure into a new file, crop it to size, but here I "export" as a PNG choosing the highest quality possible, and the result is a file that is of mediocre (barely acceptable) quality with a size of 12 KB.

The results I've had so far are pretty good, but I'd like to know if there are any tricks to shave a few extra KB off.  A couple of things annoy me too:  First, JPEGS seem to look horrible for the size they are, second, I just bought CS3, and doing the same process for PDF and PNG results in a file that is 2-3 time as large as when I use CS1!  I was hopeing that the much newer CS3 would have more advanced compression methods, or at least be as good.  It is annoying to have to keep CS1 around on the computer.  What gives!?

Can you give me any tips about ways to get the file size smaller?  I've tried making the document size smaller (from 8.5x11 to 1.5x0.5), but the sizes didn't change.  My files use very few different colors, is there some way to save using fewer colors do reduce file size?  Any suggestions would be great.

Thanks -- Adam

Answer
Hi Adam,

You should probably be using the "Save for Web" command instead of exporting or Save As. You'll get much smaller file sizes and can save as PNGs or JPGs.

Before choosing save for web, be sure to clear your crop area, if you've got one defined by the crop tool, that is... and after you choose save for web, make sure to uncheck the Clip to Artboard option found in the Image Size tab. That will restrict the web graphic's size to the boundaries of the artwork and eliminate all superfluous white space.

PDFs are probably not ideal for figures. They're just jpegs... If you do need to use them, there are indeed more and better options for PDFs in CS3.

Oooh, very few colors in your images beg for GIF format... can't use GIFs, huh?

-Amy