You can buy a collection of these small gels which you can put over your flash. I've slipped it under the wide angle cover on this Canon 430ex II. This is the set of gels I bought from B & H: http://www.bhphotovideo.com/c/product/649244-REG/Rosco_Strobist_55_Piece_Filter_Kit.html They have a hole in one corner. I put them on a large loose leaf ring for easy removal. There are kits available for flashes which combine a holder and fewer filters. You don't really need all the colors that were in this set.