Usually I stay out of these, but.........
Lets look at some facts;
1) We have seen a D&RGW paint spec card that clearly states that the boiler jacket, dome rings, compressor jacket and cylinder jackets (that is all of the sheet metal on the exterior of the locomotive) is to be painted green.
2) There is much anecdotal evidence (that is stories told by folks who were not only alive in the time period in question, but actually claim to have seem the locomotives in question with their own eyes)that the Rio Grande painted the boiler jackets et all green.
3) This all took place in an era where color photography was non existant to very rare at best. Dark green and black often "look" the same to black and white film. Add to that the fact that coal burning steam locomotives spew black nasty stuff all over themselves and it does not take long for the locomotive to paint itself black, regardless of the actual color of the paint below the grime.
Here we have an actual color photo of a fairly freshly shopped and clean 318 that clearly shows that it has a GREEN boiler jacket, dome wrappers, cylinder jacket and compressor jacket (yes, their is one over the steam side of the compressor as it is insulated, like the boiler) The green paint corresponds to the aforementioned paint card.
Note also the silver (or perhaps white) striping/highlights on the running boards, driver tires, tender tank, tender journal boxes etc. These are things that are listed on the paint card but the die hard black only fans insist "never happened" etc. Clearly, these are not "reflections"
As for the green being the parts, "reflecting the light differently", I am having a hard time buying that this little bit of magic happens only on the parts that are called out to be painted green.
As for those who don't "like" the green paint, may I paraphrase the great Clint Eastwood; "Like's got nothing to do with it"
Personally, I don't "like" a lot of stuff that happened well before my time, but that does not mean it did not happen, no matter how much I may detest it. All factual evidence points to the fact that the Rio Grande painted boiler jackets green at some point in the past. Really, they did, wheather we like it or not. No need to get mad about it, it just is.
Jason Midyette