Rendering with custom texture (reflectivity)

Visualization

About built-in and 3rd party, classic and real-time rendering solutions, settings, workflows, etc.

Hi,

Can anyone explain why it happens so that sometimes textures have intense reflectivity on renders. I was using Cineware and standard renderer. First image shows that my custom painted texture (gray one - right gable wall) is very reflective on top and Archicad stock texture (red) on the bottom looks normal. Have this happen a couple of times, but I think both of those times it was custom painted texture. I paint textures with gimp and then just import images to basic and Cineware tabs under surfaces.