For purposes of the tax imposed on photographs, negatives, and positives by this Act, “photoprocessing” includes, but is not limited to, developing films, positives, negatives, and transparencies, and tinting, coloring, making, and enlarging prints. Photoprocessing does not include color separation, typesetting, and platemaking by photographic means in the graphic arts industry and does not include any procedure, process, or activity connected with the creation of the images on the film from which the negatives, positives, or photographs are derived. The charge for in-house photoprocessing may not be less than the photoprocessor’s cost price of materials. In transactions in which products of photoprocessing are sold in conjunction with other services, if a charge for the photoprocessing component is not separately stated, tax is imposed on 50% of the entire selling price unless the sale is made by a professional photographer, in which case tax is imposed on 10% of the entire selling price.