Hello,
i rendered a large resolution image and as you can see on the pictures, there are grey splotches on bump places of first image (large resolution rendering) and no splotches on second image (small rendering). Is it bug or I’ve done something bad?
Thanks for answers and sorry for my english 
Re: Bump map problem in large resolution image
Hmm, no idea what it is. If you used jpg textures, than try png instead. Some times it helps.
Re: Bump map problem in large resolution image
I think it might actually be related to some IR map setting…those look like interpolation artifacts to me. Maybe post you’re IR settings as well as your workflow for hi res.