For now I think taht template representation would be best. What i mean is for example struct rgb_8888 { unsigned char r : 8; unsigned char g : 8; unsigned char b : 8; unsigned char : 8; }; struct yuv_422 { unsigned char y : 4; unsigned char u : 2; unsigned char v : 2; }; template<typename Components> class color { private: Components mComponents; }; A few typical "structs" will be defined and if user has a special need (perhabs becouse his program has a special memory representation) than he defines his own struct. Structs would also provide a standarized functions to manipulate on components without knwoing their real representation (perheps get_component(i) set_component(i) - ore something like this). I am also considerating to give something like color_traits, but it is a project now and i don't know if this would be realy needed. color class would give functions for manipulating on color, but no additional data members. I am now working on this but i think it can be good aspecialy because of templates which allows inlining simple functions and produce fas code, what is neede in such class to be realy used in graphic manipulation. Also using templates, as I hope, produces high extensibility (user may add his own format). Adam Badura