In article <d28rdi$4jf$>,
"Teun" wrote:
Anyone a good tip how to change any color to white? I use Color Balance and Hue Saturation to change color but this doesn’t work for white…
Changing one color to another color that is roughly the same luminosity (say, changing a red car to blue) is quite easy. On the other hand, changing something’s luminosity by a large amount–making a red car white, or a green car black–can be extraordinarily challenging, depending on how much detail is in the object and how far you are changing the lightness or darkness. Changing something that is black to white is very difficult indeed.
If you want to make an object white, one place to start is by using the Hue and Saturation command to reduce the saturation to zero. This will remove the color, leaving it gray. From there, you can use any of a number of techniques to lighten the gray to white; the first and easiest that springs to mind is the Curves command.
This assumes that you are working in RGB. If you are working in CMYK, it can get a lot more complicated, because the CMYK object probably has some black in it, which you should not have in a white object–but you can’t simply get rid of what’s in the black channel, because it likely carries a lot of the detail. Nor can you just remove the color by using Hue and Saturation, as this doesn’t produce a neutral gray;; in CMYK, neutral gray has more cyan than it has magenta or yellow. Converting an object in a CMYK image to white often begins with a trip to the Channel Mixer, where you can get the object as neutral as possible and pull some of the black channel out, placing it in the other three channels to preserve detail. From there, you can use Curves to lighten the result toward white. If the object is a very dark color, you may find it useful to copy the thing you are trying to make whit into a new file, converting it to L*a*b color, reducing the saturation, using Curves on the Luminosity channel, and then separating the result back to CMYK.
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