Alpha channel: srgb(X,Y,Z) looks different than srgba(X,Y,Z,1)?
Posted: 2015-12-31T13:19:04-07:00
I have two images. The first appears darker than the second (both in Preview and Chrome).
But one is full of srgb(38,156,120) pixels, and the other is full of srgba(38,156,120,1) pixels.
Why do they look different?
But one is full of srgb(38,156,120) pixels, and the other is full of srgba(38,156,120,1) pixels.
Why do they look different?
Code: Select all
➜ convert alpha_off.png txt:- | head
# ImageMagick pixel enumeration: 60,52,255,srgb
0,0: (9766,40092,30840) #269C78 srgb(38,156,120)
1,0: (9766,40092,30840) #269C78 srgb(38,156,120)
2,0: (9766,40092,30840) #269C78 srgb(38,156,120)
3,0: (9766,40092,30840) #269C78 srgb(38,156,120)
4,0: (9766,40092,30840) #269C78 srgb(38,156,120)
5,0: (9766,40092,30840) #269C78 srgb(38,156,120)
6,0: (9766,40092,30840) #269C78 srgb(38,156,120)
7,0: (9766,40092,30840) #269C78 srgb(38,156,120)
8,0: (9766,40092,30840) #269C78 srgb(38,156,120)
➜ convert alpha_off.png txt:- | sed 's/^[0-9][^:]*://g' | sort -r | uniq
# ImageMagick pixel enumeration: 60,52,255,srgb
(9766,40092,30840) #269C78 srgb(38,156,120)
Code: Select all
➜ convert alpha_opaque.png txt:- | head
# ImageMagick pixel enumeration: 60,52,255,srgba
0,0: (9766,40092,30840,65535) #269C78FF srgba(38,156,120,1)
1,0: (9766,40092,30840,65535) #269C78FF srgba(38,156,120,1)
2,0: (9766,40092,30840,65535) #269C78FF srgba(38,156,120,1)
3,0: (9766,40092,30840,65535) #269C78FF srgba(38,156,120,1)
4,0: (9766,40092,30840,65535) #269C78FF srgba(38,156,120,1)
5,0: (9766,40092,30840,65535) #269C78FF srgba(38,156,120,1)
6,0: (9766,40092,30840,65535) #269C78FF srgba(38,156,120,1)
7,0: (9766,40092,30840,65535) #269C78FF srgba(38,156,120,1)
8,0: (9766,40092,30840,65535) #269C78FF srgba(38,156,120,1)
➜ temp convert alpha_opaque.png txt:- | sed 's/^[0-9][^:]*://g' | sort -r | uniq
# ImageMagick pixel enumeration: 60,52,255,srgba
(9766,40092,30840,65535) #269C78FF srgba(38,156,120,1)