White-point

[Bonzo]

I had assumed that White-point could be used to set a photos white balance but it has no effect; am I using it correctly or should it be used in conjunction with another operator.

Or am I assuming it can be used for white balance but in fact it does something else?

Code: Select all

convert IMG_6191.jpg -white-point 687,518 white-point.jpg

687,518 is a point on an image that should be white but the point and whole photo has a yellow tinge.

[fmw42]

I think it just sets the chromaticity white point, but am not sure what that really means or if you have to use -set whitepoint.

If you want to adjust the white balance, see my script, whitebalance.

[glennrp]

I think it just sets the chromaticity white point, but am not sure what that really means or if you have to use -set whitepoint.

If you want to adjust the white balance, see my script, whitebalance.

Correct, the "x" and "y" have nothing to do with the x,y position of a pixel on the image. Instead, they
are coordinates of the white pixel in the chromaticity diagram (see the color diagram on the right of the page at http://en.wikipedia.org/wiki/Chromaticity)

[Bonzo]

Thanks for the info glennrp - it still has no effect on my image and I pressume it needs extra operators to have an effect.

I will try out your white point script as well fmw42.