Created attachment 142738 [details] astroimagej and irfanview screenshots It would be very nice to have a setting that can automatically adjust "contrast" when viewing Thumbnails and Previews. This would be Very helpful when browsing through my astronomy .FITS files, and probably "normal" images also. For astro images the "data" in the image is in a very narrow range of the image histogram and when browsing, digiKam Thumbnails or Preview there is never enough contrast. What I'm suggesting is something like the Color Auto-Correction feature in the Image Editor. Many astronomy programs have a feature when they display image (thumbnail, etc.) it bases the low/high (black/white points) on the mean image value +/- a certain fraction of the standard deviation of the image (follow me?) For example a 16bit image has a mean value of 16,760 and a standard deviation of 1434. The program (in this case AstroImagej - see attached file) will set the low/black point at 16,760 - (0.5 * 1434) = 16,043 and the high/white point at 16,760 + (2 * 1434) = 19,628. This gives excellent contrast to see the "data". Some basic image browsers have a similar feature where you can force the Gamma to a certain value, but this doesn't always work very well. See the IrfanView screen grab attached. Hope this was clear, sorry for the lengthy post. Many thanks again!
I guess I should explain why I made this request. All astro photographers review their images before working on them - trying to make pretty pictures (not my case), or doing science imaging (my case). One of the first steps is to weed out the good images from the not good (clouds passed by, telescope tracking errors causing trailed stars, airplanes or satellites (sadly becoming a serious problem with mega-constellation satellites like Musk's Starlink), etc. digiKam would be excellent for this! There really isn't any software I've found that will easily and quickly do this. Plus the ability to also be a image management tool is a huge plus for all doing astrophotography. Thanks again for your consideration.