How is the colour of a roughcast wall adjusted?

How is the colour of a roughcast wall adjusted?

Sometimes you will see a dark brown, sometimes a grey, sometimes a beige...how is the desired colour achieved.

Had my house roughcast beige and i asked them to roughcast below the bellcast a dark brown so it contrasted but it ended up pretty much the same way as the top...guessing they have cut a corner on materials somehwhere.

A small section was missed (not their fault) at the bottom side of the house and i wanted to patch it in, hardly noticeable but knowing its there is annoying me. Not sure how to get the colour but.

ta

do you mean in good old sand and torment render mate if so theres a few ways,coulor of sand,cement,and dyes,but the dye buisness was a bit hit and miss,the right colour of shingle/spar/stone can all so make a big difference.

I don't think your tradesmen have cut any corners with your job. When render/roughcast is first put on, no matter what the colour,, it looks dark, but when it dries, it'll alway go much lighter,,, even a black dyed cement rendered plinth, looks crap when dried out. See if you can get a breathable Weathershield paint in the colour you want, for painting the render, below the bell cast bead.
As regard to getting the colour right for patching the bit of roughcast that was missed,,, you'll never get it exact. Roughcasting is a one shot job,, if you don't get it all the first time, you will always notice any patching that's done, or the difference in colour. You can make it look presentable, but you wont make it totally invisible. Even if you went back with the "exact mix colour" of render and patched it,,, you'd still see it.