Applying Luminance destroys color

[mstriebeck]

Hi,

I have a weird effect that I have not seen before:

Here is one of my images only in RGB: https://drive.google.com/open?id=0B0KcEqw-v71VNWJESENtQXFtSTA

When I apply my Luminance image, I get this: https://drive.google.com/open?id=0B0KcEqw-v71VOEl5MWJ3QmhwRHc

If you zoom in, you can see that the Luminance image increased the detail and decreased the noise. But the color is almost destroyed. I think I could reconstruct it with curves and saturation. But I wonder why the luminance image changes the color so much in the first place.

Here are the FIT's if you want to check them out:
RGB only: https://drive.google.com/open?id=0B0KcEqw-v71VY1lMN3dFdzBDU00
Luminance: https://drive.google.com/open?id=0B0KcEqw-v71VTXZfZnpZeWhEbzA
Luminance+RGB: https://drive.google.com/open?id=0B0KcEqw-v71VQTNNeHZINXROb2M

Thanks for any ideas!!!
     Mark

[sharkmelley]

You say you "apply" your Luminance image to the RGB data.  However you don't explain what method you use to apply it.

Mark

[mstriebeck]

Sorry, yes, that would help.

I use LRGBCombination, select my Luminance image for Luminance. Leave the other Channels (RGB) empty. And then use the "New Instance" button to apply this to my RGB image.

    Mark

[pfile]

if you are doing this to the linear images, that's why it does not work. LRGBCombination has to be performed on nonlinear images which have been subjected to similar stretches.

it seemed to work OK for me on your data as long as i did autoSTF+HT to both.

rob