- Paper and printer
- Laminator or possibly clear tape
- Window, monitor, or other source of back-lighting.
Step 1: Create the Screen
So you need to produce a set of evenly spaced, black vertical bars with clear windows between them.
The way I did this was by printing out a drawing I made in mspaint with the exact pixel sizes I wanted. The bars were three times the width of the spaces between them, allowing for four frames of animation. I don't think it's the same size as my original, but I've included an mspaint file with the bars and drawing I used for my example gif. It has five frames. Feel free to download it and print it out at whatever scale you'd like to work at. Once you have your bars drawn up, print them out . You will then need to cut gaps between each one. I accomplished this by folding the paper perpendicular to the bars and carefully cutting between the bars with scissors. You can still see the fold if you look carefully at my completed screen.
You should now have a delicate paper screen with loose black vertical strips. To keep everything in place, you'll want to laminate them flat. If you don't have access to lamination, you could probably also just use some clear packing tape and apply that very carefully to keep all of the pieces where they need to be.
Trim the excess paper and make sure that the bottom edge of the screen is perpendicular to the bars. This will be important for playback later.
Step 2: Draw Your Frames
Make a pencil outline of each frame you want on a sheet of paper, superimposed. They will appear exactly where you draw them, one at a time. Keep in mind the number of frames you want, and if you'd like a smooth loop make sure that the size of one cycle is evenly divided among your frames (assuming you want a constant speed). You can see here that I've made a rotating cube, and divided one cycle (a 90 degree rotation) into four frames. At this point, each corner has moved to the next corner's position and the animation loops.
You can use some kind of back-lighting to find out which parts of these frames need to be darkened. Fold part of the bottom of the paper with your drawings up and back so that you can nestle the screen behind your drawing surface while ensuring that it is at a consistent angle with respect to it. Starting with the first frame, completely fill in the gaps (and ONLY the gaps) that fall within your drawing. Be careful not to draw over the bars, as any markings made there will show up in other frames. Once you're done, carefully slide the screen over until the lines for your first frame are just covered by the edge of the bars. Now draw in the lines for the next frame. Rinse and repeat until all frames are completed. The lines for your last frame should be butted up against the lines for the first one, allowing a smooth loop.
Step 3: Animate!
You're done! All you need to do is flip that bottom fold on your animation sheet so that it's in front. This allows you to sit the screen in it, square it against that crease, and slowly slide it across the drawing. If your angle is right and you're going at a good speed, you should see your animation come to life!