Quote:
Originally Posted by rustigsmed
hi col,
make of it as you will. it was done pretty rough and quick - thus why i hadn't uploaded.- i also was sloppy around the cats paw.
i think you are better off making it a bit more contrasty in the darker areas it helps with the banding.
pretty much selected the banded areas and used selective colour sliders.
also increased contrast and i think slightly moved the black point to the right in levels.
your original is attached on the right.
cheers
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Increasing the contrast certainly helps. I've added one that I did a week ago on the original (the 200kb version) in Instagram.
Quote:
Originally Posted by Placidus
Shouldn't matter a great deal. What it actually does:
- On each scan line, finds all data fainter than a specified centile brightness. (there's a slider, but the default works well). This helps it ignore stars and bright nebulosity, and concentrate on the background.
- Calculates the brightness of the background on that scan line.
- Bandpass filters the resultant background brightness to get a smoothed estimate of the corduroy pattern.
- Subtracts that from the image.
So it doesn't matter so very much when it does that. But I tend to do it earlier rather than later.
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I tried it, it looked like it was doing something but didn't seem to have any effect on the large banding. Maybe the banding is too large to get an effective background bias?