# strange artifact in two-color images (Intel Mac)

**URL:** <https://psychtoolbox.discourse.group/t/strange-artifact-in-two-color-images-intel-mac/698>\
**Category:** Uncategorized\
**Created:** [March 5, 2009, 9:11am UTC](https://psychtoolbox.discourse.group/t/strange-artifact-in-two-color-images-intel-mac/698 "2009-03-05T09:11:10Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Allen\_Ingling](https://avatars.discourse-cdn.com/v4/letter/a/a183cd/32.png) [@Allen\_Ingling](https://psychtoolbox.discourse.group/u/Allen_Ingling)\
**Post date:** [March 5, 2009, 9:11am UTC](https://psychtoolbox.discourse.group/t/strange-artifact-in-two-color-images-intel-mac/698/1 "2009-03-05T09:11:10Z")

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I am trying to draw a simple two-color image (e.g. any pixel in the   
image is either red or blue, and no other color appears in the   
image). The image is a 2-D plane with each pixel pointing to a row in   
a 256x3 color table. I put my two colors in the first and last row of   
the color table, and every pixel in the image is either 0 or 255.   
When the image is displayed ('DrawTexture') there is a line drawn in   
a third color (black or white, depending on the color map that I   
started with) anywhere there is a boundary between the two colors.   
This seems like a bug, because this same code worked fine back when I   
was running PTB on a PowerBook (Motorola processor). I checked the   
image by viewing it in a MatLab figure using the image() function,   
and it looks fine. By the way, I am using MatLab R2008b. Please let   
me know if you can help to solve the problem.  
Thanks!  
Aaron Schurger