Copy colour information of one image to another

[budgy]

Hiya, I really hope someone can help me out here. A while back I read a really good tutorial, which taught me how to copy the colour information of one image and apply it on to another image. I found this particurally useful when merging two images together, because this way they looked better blinded. The problem is ive forgotten how its done, and i cannot find the tutorial

If anyone can help i;l be very thankful. If a clearer explanation is required of what im trying to achieve, then please do let me know

Thanks in Adavance!


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