The Riteway holders have a clever little button which prevents the darkslide from being pulled unless the holder is in a camera. This interlock does not work correctly in some cameras, which would, I expect be a major hassle. Virtually all photographers use the two sides to distinguish between holders which hold exposed fim and those which hold unexposed film. Different photographers use different systems to distinguish so if you find yourself sharing or borrowing holders with another photographer you will need to make sure you both understand what convention is used. ONLY a white side showing holder is ever loaded into a camera to be exposed.
Regular holders are simple, reliable devices.
Readyloads and Quickloads Kodak and Fuji also sell 4x5 film in a preloaded form. The Kodak system is called Readyloads , and the Fuji system is called Quickloads . Both systems involve the film being in a cardboard envelope-like packet, which is inserted into a holder, which is in turn loaded into the camera. Instead of withdrawing a darkslide, you pull the cardboard envelope part way out, which leaves the film in the holder, ready to be exposed. After exposure, you run the cardboard envelope back in, and then withdraw the whole light-tight packet from the holder.