This is an old problem. You bought DAZ textures didn't you? They have two versions of the MAT pose files. One is for PPP and one is for P4. PPP uses bump maps that are JPEG's. P4 uses bump maps that are BUM and huge. You used the MAT pose meant for PPP and applied the JPEG version. This causes the sooty effect. You do not want the JPEG bump map in your Poser unless you get PPP. You do not need the PPP version of the MAT unless you get PPP. DAZ was a bit unclear in how they named the files.