Quote:
Originally Posted by Solitarian
Thanks Russ, much appreciated. 
I've been using gimp but it can only handle 8 bit tiffs and doesn't handle CR2 files. It was a case of lose info in the finished stack file or convert prior to stacking. Gimp works well and is easy to use, I just couldn't find a permanent fix for handling the input of files.
Now it's too easy, stack the raw files and straight into photoshop. |
No worries
glad I could help out. I wasn't aware GIMP was 8bit format only.
Quote:
Originally Posted by chiaroscuro
Sorry to revive this thread, but I've run out of ideas.
After spending the weekend going through every sub, picking the best by looking at the image and the histogram, I then used the Canon EOS software Digital Photo Professional to tweak the RGB histogram which improved the image quality substantially. I kept a copy of unmodified subs too. All were ISO 1600 at 30 secs, with matching darks and bias frames.
Then I stacked the unmodified subs - poor result seen below, and stacked the modified subs - little improvement in image. Neither could I do much to improve them in Startools or nebulosity.
The same problems seem to be there, the main ones being a green cast, poor colour and contrast overall, which I can't seem to improve with processing.
Both stacking sessions took about 10 hours each, using median sigma clipping on the subs and bias frames as recommended by DSS and youtube tutorials.
I still though get a left sided RGB histogram, and the diagonal dotted line is always diagonal! Never a sigmoid curve as it is in any other images I've seen online of the final stacked file.
Below is the final stacked image of both sets of subs, and one sample image of the modded subs I used, which looks so much better than the stacked images!
I'm lost.
Luke
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Hi Luke I wouldn't alter the subs before stacking, stack as is, then import into another program where you can adjust the histogram and curves to tweak the photo (I'm not sure you found a Mac solution yet?). DSS is very hard to control the image after stacking because it is in 32bit format and smashes your computer's memory. If you can upload a stacked version somewhere I will have a go at processing it for you (as I mentioned earlier I wouldn't bother with bias frames with a dslr).