Quickly correct mismatched tone or color between stitched and merged layers in PS?

Question

Imagine you have a panorama photo, stitched together from multiple pics, and it's already been merged into one JPEG. Each pic had a slightly different brightness/color/tone. So you can see obvious lines between the stitched images where the colors don't match.

Is there a way to correct this semi-automatically, in any version of photoshop? Other programs welcome too.

This pic might illustrate it better. The quarter itself is ok, but the white area to the right, the black area near the bottom, and the wood platform at the bottom right all feature these rectangular mismatched color areas.

Am I stuck selecting each rectangular area manually and then lightening/darkening it by eye?

Answer 1

My suggestion in this case would be to use the Healing Brush and Clone Stamp tools to smooth out the background rather than trying to adjust each layer individually.

It's not an automatic fix, but I don't believe there is a truly "automatic" way to fix those lines other than color-correcting the images beforehand. But you still might run into issues that way even.

Edit: Another thing you might try is adding a Layer Mask to your layers and then using a soft-edged brush to smooth out the hard lines.

Answer 2

I have had some luck using Image > Adjustments > Match Colour, and playing around with those settings to get the differences smoothed out. But that would really only work if you have the original files and/or layers still available.

If it's already flattened to a JPG (like I believe you mentioned), then I thinks it's time to fire up the Stamp, heal, dodge, & burn tools and try to fix it manually. If you try with adjustment layers and masks you'll probably just end up wasting a lot of time. (IMO)