

Just for the record, I have yet to find a case where the white lines print - but this is a good way to ensure peace of mind (especially for your client). If the white lines are still there when this setting is turned off, then the lines will appear when the file prints. If the white lines then disappear, you know it’s simply a screen issue due to the antialiasing. In Acrobat preferences for Page Display, UNCHECK the option marked Smooth Line Art. Here’s what I usually instruct people to do, since the biggest issue is wondering if the white lines are going to appear when the file is printed: The white lines are actually an artifact of the kind of antialiasing that Adobe products use. But again, those don’t show up much anymore. There have been other issues with white lines, such as this old CS3 problem with PSD files (which I haven’t seen in a long while) and this even older bug in CS3. If you do see white lines in Acrobat, check the Page Display preferences, and make sure “smoothing” is turned on:

There’s another good trick: Never assume Preview (or any other pdf reader) is giving you an acurate, um, preview. In fact, I can’t even force Acrobat 9 Pro to show me those lines in the image above. I think the reason it’s rare to see this is that Acrobat has gotten smarter. This used to be a huge problem, but it’s gotten more rare as time has gone by. If they do get thicker when you zoom in, then they’re really there. The best trick I ever learned for dealing with these came from Michael Stoddart, who said: Zoom in and out! If the white lines are always one-pixel thick (they don’t get thicker or thinner), then they are just screen artifacts and you can probably ignore them. See the thin white lines around the trapazoid at the top and around the text at the bottom? In the vast majority of cases, this appears only on screen! Sometimes it shows up on low-resolution printers, too, but virtually never in high-res commercial output.

The result is that sometimes white peeks out between them. But these opaque areas have to fit together like a mosaic, each piece right next to the next. PDF version 1.3).įlattening transparency means “faking it” by creating opaque areas that look transparent. Have you ever opened a PDF file and seen thin white lines where there shouldn’t be any? In general, the white lines, or “light leaks” are due to a PDF that includes flattened transparency - transparency effects (such as placed PSD files) in a file saved in a file format that doesn’t support transparency (such as Acrobat 4, a.k.a.
