Quote:
Originally Posted by Quoth
No, the contrast is lower.
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Wrong:
Read and try to understand!
Adapted:
Quote:
Weber contrast
(I − Ib)/Ib
with I and Ib representing the luminance of the features and the background, respectively. The measure is also referred to as Weber fraction, since it is the term that is constant in Weber's Law. Weber contrast is commonly used in cases where small features are present on a large uniform background, i.e., where the average luminance is approximately equal to the background luminance.
Michelson contrast
Michelson contrast (also known as the visibility) is commonly used for patterns where both bright and dark features are equivalent and take up similar fractions of the area (e.g. sine-wave gratings).
(Imax − Imin)/(Imax + Imin)
with Imax and Imin I representing the highest and lowest luminance. The denominator represents twice the average of the maximum and minimum luminances.
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Only the brightness is different; the contrast is unchanged according to both Weber and Michelson and is verified by spectrometer measurements - no difference to e.g. Kobo Sage.
And for those who know the basic arithmetic- assume example 2 has 50% less light:
Weber:
I=10, Ib=1
I=5, Ib=0.5
(I − Ib)/Ib
9/1=4.5/0.5
Michelson:
Imax=10, Imin=1
Imax=5, Imin=0.5
(Imax − Imin)/(Imax + Imin)
9/11=4.5/5.5
Proof: less light means darker, but unchanged contrast