There is no trick photography here. Both of these canvas rolls meet military requirements for the same application. A lot of these specs date back to WWII or before. If you were the military and you were trying to send hundreds of thousands of vehicles, tanks, and armor quickly into the field, would you care what shade of olive drab the top was? There is also the probability that whoever acquired the material was color blind (7 percent of men are). In true military fashion, once the product is in use and on the books, it is very hard to change it.