D.C. Mun. Regs. r. 9-458
The development and printing of pictures; and the sale of films, frames, cameras, completed photographs, photostats, blue prints, and similar items by photographers, photofinishers, and photostat producers are sales of completed tangible personal property which are subject to the sales tax. The tax shall be collected on the total selling price without deduction for the cost of the property sold, labor, service, or any other expense whatsoever.
Persons engaged in the processing of color films who also mount those films in frames are considered to be engaged in the sale of tangible personal property and shall collect the tax on the total charge or selling price.
A person under this section who renders services, such as retouching, tinting, or coloring of photographs belonging to others, is performing a taxable service and shall collect tax from the customer.
D.C. Mun. Regs. r. 9-458