I read in an old modelling book some years ago that all colors should be diluted with white for scale effect. It had formulas for each scale. I build mostly 1/72 scale and have been using colors straight from the bottle. I may need to start lightening the paint a bit. I need all the help I can get sometimes ! My paint jobs are neatly laid down, no seams, no glue globs, but my builds are lacking some "snap".
Hi, Modelnut,
Ian Huntley was a noted aviation colour researcher. He recommends the following scale/mix ratios to match colour perceptions under northern European lighting conditions:
1/144th scale - add 7% white to the basic colour
1/72nd scale - add 15% white to the basic colour
1/48th scale - add 10% white to the basic colour
1/32nd scale - add 23% white to the basic colour
This is reported in Brett Green's Osprey Book, "Airbrushing and Finishing Scale Models." Hope this helps. Good luck!