Back in 2014, I got an old Girl Guides 10ft ridge tent for 1940's camping. Since it was white, I painted it in green shed paint, both to change the colour and help with waterproofing. Due to the white canvas it dried much more pale than I expected ( shown below ). I made do with the light colour until recently, when I decided to try and dull it down further.

I got some Ronseal Forest Green and Dark Oak shed paint and tried a 2:1 mix to get olive drab. I painted a small sample of white fabric and took it out to the garage. At the first try, it was a pretty good match to the Jeep roof canvas, so I mixed up 10 litres to repaint the tent again. Due to its size and floor space in the workshop, I've been painting it in sections.