I am having trouble finding an Olive drab paint is not too dark. I am using acrylics. Tamiya mostly. The Olive drab they have is very dark and does not look right on scale models.IMO. What should I use to lighten it up? I have tried white but it seems to turn it brown and lose the green. And yellow doesn't really lighten it up much but rather changes the shade. Is there another combination that will work better? Any advice appreciated.