According to my friend Mike Trent, he interviewed several former C&S crewmen, and they states the roofs were painted with the rest of the car. I also have seen a couple pics with a black tarpaper roof. I have five in my fleet, and I have all but one with painted roofs.
I have been working on my caboose fleet lately. The RRobb book has a photo of (I think) 1003 from above during the last years of operation, and it appears to be a tar paper roof. What is distinct is that the roofing has deteriorated and the topping has worn to a light color. I could not locate that particular image, but found this one on the DPL site:
Overland painted cabeese come in a red color with grimy black roofs. I have one caboose which is unfinished that I plan to paint to match the rest. I am contemplating weathering the roof to show some wear. And yes, Derrell, I plan to weather the roof walks to a natural (albeit dirty) wood color.
I have the three painted models lettered now, and need to get glass in them and add some light weathering. It is so nice to see lettered models on the layout. I also need to add the air lines and coupler lift bars--and maybe on one or two the long hose with the whistle and air pressure gauge for reverse movements.
I haven't found anything to substantiate black roofs on rebuilt (1908) C&Sng cabooses. I haven't found anything to prove they never had black roofs either. Photos around that time are not very common but those that exist often portray the red cars darkly. And they are often taken in strong light which would lighten top surfaces. Edges of roofs sometimes appear darker compared to the surface of the fascia and sides - but that could be the function of the angle the edge surface is to the light source. Photos taken prior to the early '30s are not reliable in conveying the tone values of reds and black. I paint the roofs black on the "logic" that they could have been black initially but probably went to red as a less complicated measure when shopped thereafter. I like how they look that way but I don't guarantee that to be correct.
Interesting question, because just about any opinion is correct.
My belief on the color of the caboose roofs is that there was absolutely no effort made by the C&S to distinguish the roof color any differently when they were painted in the shop. They were painted in exactly the way a boxcar would have been painted. (including the FRA requirement that walkways not be painted)
However, over time, as the roofs were covered with tarred roofing material, it is easy to imagine (and even see in photos) that dirt, soot and even tar itself would have bled through the paint causing them to appear as a darker and different color, even on the edges.
So my answer to this question would be an unequivical "Red", because that's how the C&S regarded them. But in reality, because they clearly can appear darker, whatever appeals to your eye is fine.
Bear in mind that on the C&S the roof color of passenger equipment was also the same as the body color, so there is consistency in this.
Having said all that, there is at least one exception to this. Tim Schreiner found a photograph on ebay last summer and sent me a copy which was quite interesting. It shows #1003 at Idaho Springs, I believe in 1939. The undercarriage is painted black (not red), and the roof is for sure either unpainted dark roofing material, or was indeed painted black. But this was 1939, and is almost certainly the only one painted like that. I do not believe #1009, which was in service till 1943 out of Leadville, was ever painted in that manner. But it probably also never was in the Denver Shops after '37.
I have three OMI cabooses, all of them are painted in Floquil Zinc Chromate Primer, all red. A little weathering later, perhaps? Maybe.....
Tim Schreiner found the picture that I referenced above that I said was, in my opinion, the exception to "the rule".
This photo is probably taken around the same time as the picture Doug posted, showing the oil burning #70 and in the distance a caboose with a very black looking roof.
As you study this photo, you will see quite a bit of oil residue, but the cupola roof is absolutely black roofing material. The egdes of the roof over the facia appear to be painted, with residue, but it is likely that the roof is also black like the cupola.
Note too, that the pedestals and brake cylinder have been painted black.
Finally, note the chalked date of "9.21.39" on the body, so this photo is close to 1940. I believe it was said to have been taken in Idaho Springs.
I remain solid that in the days prior to abandonment in April 1937, cabooses were not painted this way. But in 1939, at least #1003 was.
Thanks, Tim, for coming through with this great photo, undoubtably taken by Kindig. Wish we had more color photos!