Colors completely off after Extraction and then RGB Compositing

Software Siril
1

I have an image (Rosetta) in the form of a 24Mp jpg file. I import it as 32 bits and extract the Ha (largely red), O3 (largely green) and Hb (largely blue) channels. When I RGB compose the image back it looks perfect on the screen. When I save it as “a unique file” in jpg format it looks perfect too, although only like 1000x670 pixel. When I then saver the result ( “down pointing arrow”, top right), I get a .fits that is supposed to look like what I see on the PC screen, instead the colors are completely screwed up and the image is mostly green and white (instead or red/pink as the Rosetta is supposed to be). This must be some trivial switch somewhere.

2

Hello. Thank you for your message. However, we cannot help you with so little information.
Here is a link that could help you: How to report issues — Siril 1.2.0 documentation
We need at least screenshots

3

But my guess is : your sliders are in 0/255 while you want to get higher depth image.
In fact, you should not try to play with a JPG image. Use at least a 16bit one.

4

Hard to believe that you can’t save a perfectly decent image as it appears on the screen as an equally decent and faithful .fits, .jpg or .tif file or what have you, on your hard drive. Without totally screwed up colors. Makes no sense, to me.

5

As I said, this is a viewer sliders thing probably.
But without screenshots…

6

Yes I can post a red and then a green image :neutral_face:

Anybody else ?

7

You can be sarcastic but with a screenshot I can see how the sliders are set … But have it your way. Stay with your monochrome layers.

8

wrong. Siril - FAQ

2 Likes
9

Problem solved … Siril definitely did not like the original file imported as a .jpg

Imported the file as a .fit (a much larger file of course, 300Mb) and everything worked perfectly (used auto-stretch). Both extraction and RGB composting worked as expected. Worked fine on the .tif version as well.

Thanks guys, HWH

10

If you do rgb compositing and save as 32bit and try to open this in Photoshop you’ll get washed out colors. So you better save as 16bit and colors won’t be washed out anymore.