What can you do with underwater photos which usually have an extreme blue/aqua color cast? I’ve futzed around with many techniques, then stumbled onto this simple advice today. In a nutshell, you use “image” “adjustments” “match color” “neutralize”, then use levels to boost colors, in Photoshop. I have some really old (1989) jpeg scans from 35mm film and this did a remarkable job. These Convict Tangs were aqua colored in the original photo.