Dental Avenue Xpress SD Self Developing X-Ray Films are D Speed x-ray films which are self-developing. They don't require developing & fixing solution separately. Self-developing xray films have been advised to be used in dental clinics to save the chairside time. Xpress SD Self Developing X-Ray Films are intended to provide fast, high-resolution x-rays without the use of a dental processor. Available as a self-contained packet with a mono bath solution in one end and an adult size film in the other, the Xpress SD x-ray is fully developed in 30-45 seconds.