15 October, 2010

Bug in Photoshop Elements 6 for Mac

I found this bug in Photoshop Elements. First, start with this image:
(What you see is rescaled, the original image is only 27 by 28 pixels. I think if you click on the image it'll take you to a smaller version you can try this on.)

Use the magic wand tool, which selects pixels of similar colour. Set it to 0 tolerance, no anti-aliasing, contiguous on, no all layers and click on the first blue stripe from the left. It should only select the blue stripe, but this is what it selects:
It's selected all 3 blue stripes and all the white area! (I can't show you the selection so I deleted the selection, leaving the black background). How close is blue to white?

The paint bucket, with similar selection options, seems to use a different engine and works fine. Here I filled that blue stripe with black and it works like expected. The blue stripe in the top right also turned black because it was the same colour. You can tell I didn't turn on contiguous here.

More experiments:
  • selecting the white background works
  • selecting the resulting black stripe in the 3rd image selects both black stripes, and all the white area

OH I'VE FIXED IT
While using the eyedropper tool I noticed that I set it to 3×3 previously. Setting it back to point fixed the problem.

CONCLUSION
Magic wand areas are affected by the sample size defined in eyedropper tool. Is this a bug?

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