What reasons did they give for not doing black?

https://www.mariakillam.com/roofcolours/

https://dsbahr.com/how-roof-color-affects-your-home/

You didn't mention your whereabouts. For instance, you don't want a black roof on a house anywhere in the SunBelt because of heat gain. And shortened life expectancy for the roof. Plus, working on a black roof is doubly miserable for the roofers.

I suspect, it has something to do with heat gain, or how hot it gets for the roofers when working. I have a jet black roof, and I do live where its hot and sunny. The roof was here when I bought the house, and is probably about 15 yrs old. I havent noticed any heat gain, but, my house is also solid stone, which keeps my heating and cooling costs very low, compared to my last house. If you are asking, will it streak down your white house, no, probably not . I have never noticed any streaking on my house, and there is none down the road on a white house that has a black roof, and all black trim. The houses, I see all the streaking on, are those with very light roofs. In this area, light roofs, look old and dirty and streaked very fast.

Maybe they think you want a true black? Not sure if that exists, or if it would be ill advised, but I also wanted a “black” roof so I asked the builder what shingles we were using and then spec’d the darkest color, but I still wouldn’t call it a true black. We used GAF Timberline HD in Charcoal. Our builder didn’t raise any concerns with streaking or anything, and he is not shy about raising concerns with maintenance, etc.

The company is Sprague and they are saying that their black roof has a 30% chance of having varied coloration. That there can be whole packages that are slightly lighter and they can't tell until after installing the roof. We are doing black metal on the front lower roofs, so black is what this house needs.. Right!?

Thank you all for your input!!

Thats the name of the roofing contractor?? What is the brand name of the shingles?

Yes, I would definitely want black, since you are using black metal. It would look very odd, to have a different color on the rest of the roof. Appears you have black on there now also?

They sound like they are raising a valid concern that has to do with the brand they use. You can ask them to source a different brand, or perhaps to do as floor/tile installers do and mix the packages (might be not practical or possible as they need to get the packs up on the roof. )

Since the upper and lower roofs are angled differently, a slight variation in color might not really be noticeable, since I believe that even the exact same shade of black will look different because of differences in light/reflection and the difference in material.