Am 04.01.2011 14:19, schrieb scott:

>> For a "perceptually linear" gradient, the formula would be changed to:
>>
>> q = 1-p;
>> temp1 = pow(color1, 1/gamma);
>> temp2 = pow(color2, 1/gamma);
>> tempR = p * color1 + q * color2;
>> result = pow(tempR, gamma);
>>
>> where gamma would be a value around 2.5.
>
> OOC why 2.5? CIELAB uses a value of 3 to computer the "lightness".

Maybe this is just CIE's way of avoiding potential trouble if someone 
tries to feed negative values into the formula for converting from CIE 
XYZ to L*a*b*.

Note that for instance Hunter Lab uses a gamma of 2.0.

Post a reply to this message