EDIT: felt bad about opening a thread just for this so I’ll just use it for all the dumb questions I (you) may have in the future
Hello,
the other day I tried some basic stuff: gradually adjust luminosity or hue (anything with adjust_colors
except saturation obviously) on a few full white/or gray/ or black images (Anything that’s filled with identical values, like 45,45,45
, etc. ). And I don’t know if I’m doing things wrong again but it doesn’t seem to work.
gmic: GREYC's Magic for Image Computing: command-line interface
Version 3.2.7 (pre-release #23081322)
This just outputs white images ( All pixels@255, and adding n 0,255
afterwards outputs black):
gmic run '400,400,1,3 fc 255,255,255 repeat 10 { +adjust_colors. -10 } d0 '
The same pipeline works on color images though (R values go from 255 to 112) and this is what i expect on white/grey images (or black images if i adjust positively):
gmic run '400,400,1,3 fc 255,0,0 repeat 10 { +adjust_colors. -10 } d0 '
So I tried this, with an almost full white image (and here values go from 255 to 254.4, which is not really visible, I eexpected a bit more ):
gmic run '400,400,1,3 fc 255,255,254 repeat 10 { +adjust_colors. -10 } c 0,255 d0 '
Then I tried this and it doesn’t seem to work as it should ( is $>
recognized here?) since all images end up the same light grey :
gmic run ' repeat 10 { 400,400,1,3,255 } repeat 10 { mul[$>] 0.9 } d0 '
Obviously this works but I need to adjust images that already exist:
gmic run ' 400,400,1,3,255 fc 255,255,255 repeat 10 { +mul. 0.9 } d0 '
So my question is : how can i adjust luminosity or hue correctly on this kind of images ?
Thank you