You will want to dope the paper before you paint it. There are a few ways to go. Lately I use Top Flite LusterKote Crystal Clear # TOPR7501. You should be able to find it at a Hobby Store that sells large RC models. If they do not have it you can ask for them to order it. This is in a 10 oz spay can.
I used to use colored paper (to save weight) but my last build I used Guillow's paper, doped, then painted with Tamiya 'rattle cans' They have a large assortment of Military colors. I painted this model very quickly... Here is my 400 FW:
Markings are all photo copies on bond paper. Crosses are copies of Guillow decals. Red 13, Winged 1 Squadron mark, and tail mark are enlarged copies from reference book. Plane is Heinz Bar's with his 200 victory mark and Iron Cross on rudder.
I did not use any masking as I said I did this very quickly. 2 tone grey topsides, Luftwaffe blue underside. Black exhaust. I was disappointed with the way the yellow 'chin' came out but I was told yellow is a very hard color to work with. My model was made for flight and has suffered some damage. Damage was from a 'blown motor', also cracked the cowl during early trim tests, after that model suffer NO damage during flights. For a display model you could spend more time masking and doing a better paint job.
Have Fun, Mitch
PS Model's best flight was 28 seconds on a rubber motor and 9 inch prop... Model is currently on loan and display at Skyway Hobby Shop in Renton, WA.
Here is an early picture after trim tests and during my early flight and motor tests... After painting model was still in balance and did not add much weight... maybe 1 or 2 grams... I forget. Better flyers than I keep detailed notes... I do not.