Hi, I have several pictures of an event shot under a few different lights (natural, artificial, etc.). I did not take a picture of a gray card in all of these situations. I know that I can use any white/gray element for an approximate WB but I already have a good starting point with the auto wb and I want to do something more precise and uniform across different pictures. Now I'm wondering if I could use one specific color as a reference, like a red dress. Something like this: - I "measure" the WB on red color in a picture shot with natural light and I get a "wrong" temperature like 2900K - then I "measure" the same color in a picture with artificial light and I get 2500K So now I know that I have a difference of 400K in the two pictures and I can take the temperature of the second picture and set it to the first minus 400. From a couple of tests I think this does not work. Is there any trick like this that I could use? Or something to make a quick "color comparison" of the dress color in different photos?