100 fan shrouds were painted black (as the radiator).
100-Six, 3000. The Fan shrouds were best described as gloss "chinese Red". This was brush applied over the black.
100 fan was painted a medium red, quite similar to Colorado Red. Securing bolts on most cars were painted red.
Through the early 3000 Mark I's were painted medium bright red (at least through the end of 1960), quite similar to Colorado Red.
All late 3000 Mark I,II and III fans were painted medium yellow. A reasonable approximation of this color is Plasti-Cote brand spray enamel called "Caterpillar Yellow". Securing bolts were zinc-plated and not painted.
TH, if your going to paint your fan, I'd recommend having it power coated. I did and it resists chipping. Looks brand new and shinny everyday.
Happy Healey Motoring!
Roger