I was trying to look that up here last week. I was looking for hunter orange requirements to see if there was a % amount, or # of orange articles, etc that are needed.
Just saw a study about deer visual acuity as well. Anything in the blue wavelengths, they can see well. Anything in the red wavelengths, they have a hard time seeing. Brown/Green they can see moderately well, but have a hard time with fine definition of colors. For example, if you are wearing some brown digicamo with really fine color gradients, you will still show up as a strong blob for a deer and not have your outline broken up.
It kind of lends credence to some of that hunter orange with woods camo patterns overlayed.