When you are still in the woods, it is so easy to spot movement. That is us, deer can do it 10X better supposedly. So, the most important thing is to be still. Orange comes through like other light colors and probably is good at blending into the sky in a tree stand. I think when moving, having orange on your limbs could make it easier for deer to see you, but it is pretty easy for them to see you moving anyway.
Deer will always believe their noses, so scent control is more important than clothing color. Once they scent you they are gone. However, if they see you, many times they circle downwind to verify rather than bolt. With noises they will also come in downwind many times.