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::If you have monitor (with big contrast like 4^8=65536:1), where 255 is 4 times stronger than 128, and 128 is 4 times stronger than 64, and 64 is 4 times stronger than 32 and so on. Then by rising gamma to value <math>k_g=2</math>, an algorithm "<math>final.rgb=(color.rgb)^{1/2};</math> 0<color.rgb<1" will be applyied and you will get, that 255 is 2 times stronger than 128, and 128 is 2 times stronger than 64, and 64 is 2 times stronger than 32. Because <math>0.4^{1/2}/0.1^{1/2}=0.632/0.316=2.</math>
::If you have monitor (with big contrast like 8^8=16777216:1), where 255 is 8 times stronger than 128, and 128 is 8 times stronger than 64, and 64 is 8 times stronger than 32 and so on. Then by rising gamma to value <math>k_g=3</math> you applying algorithm "<math>final.rgb=(color.rgb)^{1/3}; </math> 0<color.rgb<1" and you will get, that 255 is 2 times stronger than 128, and 128 is 2 times stronger than 64, and 64 is 2 times stronger than 32. Because <math>0.8^{1/3}/0.1^{1/3}=0.9283/0.46416=2.</math>
::For monitors with contrast 2^8=256~300:1, there is no point use gamma correction, because 1 (and even 0) shining pretty strong. So if monitors developers don't put they own calibration into monitor (that 0 is 1000 times weaker than 1 and 1 is about 300 times weaker than 255), then gamma should perfectly to let you to choose desired contrast ratio (from say 50:1 to 100000:1) by changing coefficient <math>0.5<k_g<0<3.5.</math> Good thing about gamma is that it don't rising 0 at all. So this is main advantage of big contrast monitors over small contrast monitors (which have strong 0 and contrast between 0 and is about 2:1 or at most 10:1), because if 0 is very black, then better visible weak colours like 3, 5, 10, if gamma is more than 1 (default gamma=1). But for some reason at least for old some CRT monitors contrast and brightness combined correction "contrast=100-brightness/2.55" rising too weak colours better and in correct contrast (you must judge if contrast between colours is correct by comparing 10 with 20 and 255 with 128 or 10 with 5, and if in all cases two times smaller number looks like two times weaker then contrast is correct, by correcting with gamma for some reason disappearing difference between 255 and 128 and difference between 5 and 10 is very big and between 10 and 20 very small, but it's maybe because in CRT (cathode ray tube) monitors screen becoming too negative and for weak colours it's big difference and for strong colours almost no difference, also after some
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