Another in a series of color correction tutorials from the upcoming revised edition of “Color Correction for Video” coming out in December from Focal Press.
In this installment, I show you how to sample colors on the screen in Apple Color to get numeric readouts of specific pixels in your image. (These same methods can be used with Avid or FCP or Color Finesse in Premiere or After Effects.) Using these numeric readouts can assist you in making corrections, especially if you can sample something that should be white, black or some other neutral gray tone. Any neutral tone should have the same numeric readout across all three color channels. (They can be off by a little.)
The samples in Color will continuously update as you color correct, which is very helpful. So, for example, is you sample a black pixel from your image and it says that the red channel is .085, the green channel is .088 and the blue channel is .025, then that means that your blacks have either a deficiency of blue or too much yellow (the combination of even amounts of red and green). So you probably need to raise the set-up/pedestal/black level of your blue channel to remove the yellow cast in the blacks. This will actually help balance the overall level somewhat, especially if you can balance the whites/highlights/gain using the same method. Grays will either fall into place, or you can adjust your gammas/midtones “to taste” by eye.