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Chienworks wrote on 7/9/2003, 4:43 PM
http://vegasusers.com/testbench/files/chienworks-correct-color-gradient-screenshot.jpg

Here's what i did, and it helps if you're looking at the above picture while reading this description.

On track 1 at 0 -- 2 seconds is an original picture. On tracks 2 and 3 you'll see a version with a color gradient applied, starting reddish on the left side and greenish on the right. Assume that this miscolored picture is the original that i started with. Yours varies in brightness instead of color, but the concept is the same.

I loaded the image onto two tracks, synchronized with each other, shown at 3 -- 5 seconds on the timeline. I applied the necessary correction for the right side of the picture to the image on track 2. Notice how correcting the greenish tint caused the left side of the picture to look much redder. Don't worry about this. In your case correcting the lighter side will make the darker side look much darker. Again, this is ok. On track 3 i corrected the reddish left side to look better, making the right side way too green.

The last step is to combine these two together with a gradient mask, seen from seconds 6 -- 8 on track 1. Clicking on the crooked arrow to the left of track 2 made that track a compositing child of the mask on track 1. Wherever that mask is white, track 2 shows through. Wherever it is black, the other tracks show through. Where it's grey, track 2 and the other track blend together in proportion to how bright/dark the grey is.

The result is seen in the preview window. It's not perfect, some of the shadows are still slightly miscolored. This is to be expected since the original image can never be exactly recovered, but with some care and tweaking you can get very close. The difference will probably be even smaller in your case since you're dealing with brightness instead of color.

http://vegasusers.com/testbench/files/
Contains several files. The .zip file has all the images and the .veg file (Vegas 4.0c) used in this demonstration. The horizontal-gradient JPEGs are the compositing masks that you may use. If your gradient isn't perfectly horizontal you may need to create your own mask, or play around with Vegas' mask generators.

Hopefully this isn't too complex. If i didn't explain it well enough, please ask questions!