We have all seen this, the early color snaps with the gawd awful yellow tint, banding, splotching or all the above. The chemicals used then were not archival by any means nor were the colors in the actual print. So between the chemicals breaking down and the dyes breaking down, the poor print does not have a chance of staying pristine or even likable.
I have a client who gave me 8 photo albums of old prints that are tagged to which she wants scanned. The first four were black and whites from the 30s and up to the early 50s. Then I hit the color prints. Ugh.. some where not too bad but many were just awful with the yellow peril. It took the better part of an hour to work out how to get rid of it and to script it since the normal level adjustment was not working at all.
I have some pictures below showing the method I came up which fuses LAB adjustments to RGB adjustments. The trick is to find the channel in LAB that has the crap to be cleaned up. On 99% of the color prints I’m working on, this is channel B in LAB. So we need to neutralize the yellow in the B channel only then color balance the print.
Going in LAB mode and then looking at each channel to find the bad one
Ahhh.. here we go.. channel B has the bad data so thats the one we need to tweak
One curve applied to B channel only. Fixed things right up
Pretty done at this point. I can clean up the wall some more but it is really good enough for what the client wants to do with it.
So what ended up doing since I had over 100 of these to do is to script the steps from flipping to LAB mode and applying the curve to back to RGB mode. I have it applied to a function key so I load the image and hit shift F13 and within a few seconds, the yellow is cleaned up and I’m ready to color balance the print.
The take away from this is really two items, one, learn to use LAB mode and second, learn how to use your channels. Channels are a very powerful tool in Photoshop and there are things you can do in a channel that you not do any other way.