Detail Recovery (blown highlights) in GIMP


(Stampede) #1

My usual workflow is to do global adjustments in RT, and then any local adjustments in GIMP.

My understanding now that GIMP can work on high bit depth images, was that theoretically, I should not lose any data when going from RT to the GIMP.

I want to draw your attention to the clock face in the tower. In RT, I can drop the exposure enough to get some detail out of the clock face. You can sort of see the numbers and the hands of the clock. The problem is that this screws up the look of the rest of the picture when I mess with the exposure so much.

Here is a picture that I’m working on. And the PP3.

clock 75 detail recovered.jpg.out.pp3 (11.1 KB)

So I know that there is some detail there of the clock hands. “No problem,” I think. "I will leave the clock face totally blown out, with exposure settings for the rest of the picture and then just drop the exposure in GIMP, and mask out the rest of the pic. So the clock will look more better, without screwing up the rest of the picture.

Problem is I cannot get the detail back in the GIMP. I have tried levels, curves, highlights/shadows, and exposure, but I cannot get the hands of the clock to come back. I’m working on a 32-bit floating TIFF file.

What am I missing?

Here is the pp3 for the global exposure. Notice how the clock face is almost entirely blown-out white. IMG_0075.CR2.pp3 (11.1 KB)

Here’s the Raw file: https://filebin.net/v0anf8qobng5o24o


(Thomas) #2

I think the clock face is blown out in the raw file, meaning that at least one sensor channel has reached its limit. Propably it is mainly green in your example. A raw developmet program as RT might be able to deal with this but gimp is expecting consistent color values.

Edit:
Either do it all in RT or try it the other way around. Do the clock face in RT and the rest of the image in Gimp.

This was done in darktable:


IMG_0075.CR2.xmp (3,4 KB)


#3

I have sometimes exported two (or more) TIFFs from RT and used a mask to blend them in GIMP.


(JegMeg) #4

I would first do global adjustment , and then using “Local Lab” within Raw Therapee as shown below
Check out this thread

2018-12-31_001125


(Pat David) #5

I’ve done this as well pretty often.

The highlight recovery options in RT are wonderful (color propagation :heavy_heart_exclamation:)