When I open the PDF (in Acrobat 5, viewed on a Brilliance 109P, the best CRT I could get hold of to replace my Trinitron Multiscan G420), and zoom in to 1600, I see no hairline. At intermediate zoom levels (round 200 - 400) there seems to be something at the rounded blue borders, but it could look like some screen artifact. How does it print?
Thanks for your reply.
When you said you can't even see what I'm referring to, it made me remember a possible answer
Looking at Acrobat > Preferences > Page Display > Smooth Line Art ..........
if that is un-checked the hairlines disappear but the artwork looks very jagged
If that is checked the artwork looks smooth but the hairline is visible
And it doesn't print whatever the setting
But it IS visible as a hairline on the Illustrator artwork
I just opened the file in Illy (10), and the hairline shows clearly, with the same apparent stroke weight regardless of zoom level, up to 988%. From 989% up, it is gone.
So, as with the PDF, it only shows up to a certain zoom level.
I do not have that Preferences option in 5.
So it seems it is a screen (rendering) issue.
I would not trust those hairlines to be just screen-drawing aberations. The artwork needs to be simplified.
Use your white objects to punch (Subtract From Shape Area, Expanded) the red and blue objects. When you do this, you'll find that paths are left along the problem edges, even where the white object clearly laps beyond the edges of the blue and red (suggesting something wrong with the file).
Don't use all those overlappng clipping paths. Simplify the artwork down to "literal" paths shaped like what you want to see.
Also: Although I don't think it's the cause in this case, be aware that bugs in some of Illustrator's Pathfinder operations do, in fact, result in hairline strokes (which Illustrator isn't even supposed to be able to create). The presence of these is easy to overlook because of Illustrator's antialiasing--but they can wreck a print job.
Not visible in (Acrobat) Reader 9
Visible in Illustrator CS3 and CS4
Ok... just reduce the path a fraction (and i mean a fraction - it won't affect the art)... it vanishes. You'll still get it on the right side. Then, reduce the width of the clipping mask a fraction as well and that vanishes...
Basically, there seems to be a slight mismatch between the clipping mask and the art... someone please correct my explanation...
Edit: Correction. It shows in Reader... but i didn't catch it on the secondary monitor. Also, it's fainter than in AI but it's there.