Getting results with a simple homemade lightbox

When the pictures first come in, they are very yellow tinted, even with some simple tweaks with the built in settings. I haven't been able to find any decent combination of exposure, contrast, brightness, etc. settings to counteract the tinge:

Despite the brightness of the lights, there are still some shadows cast in back of the DoubleTall ExtenderShield:


And in this picture, you can see the walls of the lightbox:



I've done it so many times, I almost have the Gimp edit sequence memorized:

1. Open the image, and crop around the right size
2. Open brightness and contrast - improve brightness by 40%, contrast by 70%
3. Use the fuzzy color select tool with 14.2 pixel fuzzy tolernace, and select the whitespace
4. Fill with whitespace
5. Size image to 800 pixel width or 600 pixel height at maximum
6. Save and upload!

The results look like this (I really like the contrast of the black board with the red min protoboards on top!):


There's still a little tiny hint of yellowish-orange tint, but for the most part you can get the idea :)


It took me about 3 hours total of camera work, editing, and uploading to snap the photos for everything you see on the www.liquidware.com site. Let me know what you think... anyone have any ideas on how I can improve next time?