seconded. green and red are complimentary colors, so if you wash one over the other it becomes a darker version of the dominant color. in any case i wouldnt recommenr it immediately -i would suggst mixing paint first. do a flat coat of the lightest color you want in the robes (not as light as the hilights will bw mind you). than wash with sucessively darker colors/ mixes of color. for reds i do blood red, red gore, than reds mixed with blacks or browns depending on the final effect wanted. than hilight away (red mixed with yellows works for this).
here's a tip I just learned. Take it or leave it. when doing red robes that you want to have depth and shadow.... give it a dark green wash. Seriously. I forget teh color theory behind it lol message JimG to find out the reason but it works. Gives depth and volume. Don't get me wrong- your robes are a good job and I wouldn't have done any better 2 months ago. But ever since I learned about washing (lol and taking baths but thats different) my fabrics are twenty times better looking. Drybrushing is now reserved to coarse fur looks.