I have the following situation:
I want to present barplots as stimuli in a EEG experiment.
To controll for perceived brightness, all three colors used (red, blue and the gray background) should have the same luminocity.
I am somewhat convinced that my red and blue came out the same in brightness, but the gray background looks darker than the bars. I haven’t had the chance to test it in the lab, but that’s the impression I get on my home-monitor.
Using the luminocity weights by the WCAG 2.0 (Y = 0.2126R + 0.7152G + 0.0722*B) i figured out the following three colors to use (the values are in psychopys system reaching from -1 to 1):
Red (just pure red): [1, -1, -1]
Blue (With a bit of green to get the same luminocity: [-1, -.6073, 1]
And Gray (where all three values should be the same): [-.5748,-.5748,-.5748]
The screen is a Samsung SynchMaster S24B350 LED and I’m runing Psychopy 1.84.2 (standalone) on Windows7.
Do I need to apply some additional gamma correction or something similar? Or is my result correct and I can’t trust my eyes?
Does someone have some more experience with this sort of problem?
Thanks a lot!