be careful. there is a big difference between IBL files and HDR files. Carrara can use both and each type can be useful. HDR files are high dynamic range type of IBL images. Using photoshop to create IBL files while very usful is not the same as the high dynamic mirror ball created HDR files. good site for imformation is http://gl.ict.usc.edu/HDRShop/ the Introduction link shows the difference of the file types with picture examples.