Expert: Amy - 3/4/2008

Question
Hello Amy,

I hope you can help.  I'm new to Illustrator.  I've just designed a
logo/letterhead for a friend.  The file contains some transparency.  When I
print from Illustrator, the text appears ragged around the edges, although
the transparency is intact.  If I save the file as a PDF and print, the
transparency does not work but the text remains sharp.

From reading around, I think the problem may be to do with the text being
rasterised as well as the transparency when I print from Illustrator.  My
question is, how do I ensure the text stays sharp AND the transparency works
when I send the Illustrator file off to the printers?

Thanks in advance for your time and help,
Tiger

Answer
Hi there, Tiger.

You're right.  When you print to an inket, you are printing a bitmapped preview but inkjets can render the transparency... because they're really just printing a raster preview.

BUT when you print to a PDF and send the file to the printer, the postscript data is used to print. Therefore, the letters are crisp.  

How to deal with transparency in your files does depend on your printer and your version of Acrobat to an extent.

But in most situations, the printer will want you to flatten your artwork.

Flattening is a simple concept - everything that has transparency (including drop shadows and other effects) must be rasterized using Illustrator's flatten transparency command. As must any object that interacts with the transparent area.

In the simplest example, you would select the object that contains transparency and overlapping objects and select object > flatten transparency. Make sure you use a nice high setting in the options, like 300dpi. You'll see a bunch of tiny white lines appear on your artwork, like a puzzle. That's a display thing only - there is actually no white gap in the postscript output.

If you use spot colors in your transparency, it can get a little more difficult and further reading is recommended...

http://www.dynamicgraphics.com/dgm/Article/28763
That's a nice concise article by Claudia McCue on transparency.

http://www.adobe.com/products/illustrator/pdfs/ai10_print.pdf
Is a long but very informative read on transparency... the whys and hows. Even though it's about v10, most holds true in newer versions... although I believe technology on the RIP end has advanced since it was written.

Well, have fun!
Amy