For asphalt you will need the old fashion tar in a can and a trough
Here in the southwest there is dirt and salts, that collects after the wind, I swept off the dirt I could feel good enough about or waited for a good rain, the cleaner it is the whiter it is, hard to clean off the dirt and salts in a desert with just a little amount of water, in a large area, I found that some dirt can be there, just rub it in good enough, with the roller I used, next coat will be whiter, therefore after applying let it dry long enough, then add the 2nd coat or 3rd coat soon enough, if its not white enough, it gets whiter with another coat - when you have bleed though. The color is better than another brand I tried, you can see a difference, this brand is whiter, there was less bleed though with this brand. I used it several years ago on gray 3 tab shingle roof and did some patching with that black asphalt paste - I waited a short time after the paste, or a day, or just long enough before painting. The directions say its not recommended for shingles yet you can see by what I wrote, it worked great, they wrote it makes them curl, I found they where curled to begin with, it gets better as it dries - I found if you wait for it to dry after applying it thick enough, it worked great for me, my shingles became flat - it keeps the shingles from flying away, do not expect to apply very little and get great results like I did. Now that it is white its cool enough to work bare foot on the hottest day to prove its cooler. I think they improved it, lasts longer than what I started with. I spread it on thick and work it in between the tabs - the notches, with a 3 foot roller and long handle - make sure you use old shoes and clothes while rolling, it can throw paint being too close to it - doing it fast. Where the roof is flat it is asphalt gray rock sheeting, it worn down and became porous, this stuff is great it flowed in to it and hardened its not porous any more. Most important is to not step in it, as you might slide off the roof.