You may see triangular regions on the object in your graphics package that have noticeably different intensities than their neighboring triangles. You may see one quite dark face surrounded by lighter faces or the reverse. This is due to PhotoModeler extracting adjacent face textures from different photographs. These photographs might have different brightness and contrast.
Imagine walking around a building taking pictures; some of the pictures may have a lot of sunlight and others might have a lot of shadow. These images vary quite a bit in brightness and contrast. The textures extracted from these photos will have similar variations in brightness and contrast.
If you just have one or two Faces that seem out of place, you may be able to fix it with judicious choice of the Photograph quality.
For more widespread intensity variations you will need to use an external image processing program (e.g. PhotoShop) to play with the intensity and contrast of the images to try to even them out.