taken from another post of mine:
My top is OD#7 ...untreated mine would get much lighter...to almost a gray/green color...but would deteriate...Treated it will get a bit dirtyer (darker) over time.
OD#4 or #3 is a khaki color ...Khaki with a greenish hue...often called "pea green khaki" this is the original "khaki" although it was really OD. this M41 jacket is a good example of color:
Reproduction Enlisted Man's U.S. M41 Jacket, O.D., Government Surplus, Brand Not Specified at Sportsman's Guide
Today Military uniform Khaki...is a tan
Mustard Tan ( on the trucks you see) (military treated Khaki):
8ft. x 10ft. Mustard-Tan Heavy Duty Canvas Tarp | Canvas Tarps | Northern Tool + Equipment
this fades much lighter quicker if untreated...not recomended