I know there has been discussion about slides from digital images before on this list and the AP list. My son is a photographer for a university here in Indiana and they use digital images for all their slides. The place they use to process the images is https://www.gammatech.com/html/recording35.htm They charge 2.50 for the first slide and 1.00 for a duplicate. He said they have had very good service with this company. This is less expensive than film since you do not have to buy the slide film to produce the slides and you can take and preview images to make sure they are right before you send them.