if your exposures are right it comes to filter 2(or no filter exept different time) If there are no filters around anymore, usually very cheap at any 2nd hand shop (and not only camera-shops) you can also see if you have a professional-light retal near you... these used to have free samples of filters in a neat little book. You can undoubtedly find the filters(colours) you need and hold it in front of the flash so you can alter the contrast in your contacts. Personally I find that my contacts look better with filter 3 though if I print I end up using filter 2 ... Baidewai: I think to establish a standard in your case you might want to stick your flash in a fixed position you can repeat easily I like your the to-use-what-is-at-hand method!