Mysterious Lines


Today’s Question: I’m using the current version of Photoshop and just recently I’ve been getting an artifact (vertical translucent red lines) appearing in the image when making an adjustment on adjustment layers. The problem is intermittent but occurs with regularity. When I flatten the image the artifact disappears. Have you any ideas on how to overcome this problem?

Tim’s Quick Answer: The fact that these lines only appear while you’re working in Photoshop and disappear when you flatten the image is a clear indication to me that the issue at play is the display adapter (graphics processor) in the computer. Turning off the “Use Graphics Processor” checkbox on the Performance tab of the Preferences dialog will most likely cause this problem to be resolved.

More Detail: The photographer who submitted this question included a sample screen shot image that showed the lines that are appearing on his photos. Those lines resemble corruption artifacts that you might otherwise see with a corrupted digital capture. The fact that these artifacts disappear when the image is flattened suggests that the issue relates to the way the image is being rendered on the screen, not the actual contents of the photo.

Photoshop (among other applications, including Lightroom) makes use of the display adapter (graphics processor) for a variety of tasks, primarily aimed at improving overall performance for the application. Using the graphics processor can most certainly improve performance, but in some cases it can also lead to compatibility issues and stability problems.

Whenever you see visual artifacts that seem to relate to the Photoshop interface, the display adapter is the most likely culprit. For example, I’ve seen issues where the mouse icons for tools will only partially appear. Fortunately, you can easily turn off the “Use Graphics Processor” checkbox to test whether that resolves the problem. In many cases this does provide a solution.

Turning off the “Use Graphics Processor” checkbox won’t have any significantly harmful effects on Photoshop, other than a potential degradation in performance for certain processor-intensive tasks. However, certain features that require the graphics processor will be disabled as well, such as the HUD Color Picker. But all of the features that are disabled can be accessed through other means, so you’re not actually losing any core features.

To access the “Use Graphics Processor” checkbox you need to bring up the Performance tab of the Preferences dialog. To do so on Macintosh you can choose Photoshop > Preferences > Performance from the menu. On Windows the same menu command can be found under Edit > Preferences > Performance.