Placing your specimen slide on top of a small fluorescent lamp will provide even, cool back-lighting. A light table used for slides works well. Overhead projectors, generally used for transparencies, can also be used. Place a piece of white paper over the projector to diffuse the light if it is too harsh. Place slides on top of the paper, turn on light table and turn off the LED lens light of the ProScope (switch on the side of the ProScope). In the ProScope software settings, set to ‘outdoor’ option for the video.
Now you can move from slide to slide much faster than placing individual slides on a microscope.
Note: When using the overhead projector in this setup, you may want to divert the projector output from the screen so that the image produced by your projection viewer connected to the computer and the ProScope is not washed out. Other light tables (usually sold as photography accessories) work well too, but overhead projectors are usually easy to find.