Losing information with levels?

[Jerry van Dijk]

When I’m processing RAW images (in Silkypix), I usually use the histogram to optimize exposure. In the upper histogram from Silkypix, I’ve set exposure so that the histogram is cut off where the red channel stops. When I continue PP (in my case in Corel Photopaint) and adjust levels, I find that the histogram there (lower histogram) only displays the white channel in default (RGB) mode. I would adjust this histogram to the red dotted line I’ve indicated in the screenshots, but apparently, this means that I’m cutting off part of the red and green channel. Does this mean that I’m losing information from the image when applying levels :confused:? I have tried to optimize each channel separately, but this results in oddly colored images. I’m curious to your knowledge and experiences on this subject.

[David Thomasson]

When I continue PP (in my case in Corel Photopaint) and adjust levels, I find that the histogram there (lower histogram) only displays the white channel in default (RGB) mode. I would adjust this histogram to the red dotted line I’ve indicated in the screenshots, but apparently, this means that I’m cutting off part of the red and green channel. Does this mean that I’m losing information from the image when applying levels :confused:?

Yes, it's clipping those channels. When adjusting the highlight slider in the composite channel, the idea is to pull it in just to the point where clipping begins, and stop there. I'm not familiar with either of the programs you mention, but in Photoshop levels, you can hold the alt key and see exactly where clipping begins. Maybe Photopaint has a similar feature. I don't know.