Every negative has certain base color, i.e. the color of unexposed areas. I want to know how to fraction this number out of my scans.
In pure math, this is nothing particularly strange, I assume that all colors are coded in RGB values between 0 and 1 and that in my scan result the base color
B is multiplied with the color information
C of the photograph. So to retrieve the original value
C all I have to do is a pixel- and channelwise division by
Unfortunately, I don't know how to easily achieve this in PhotoShop. Is there any blending mode acting as division on the RGB values? Or any other operation doing so?