"ABRASION HOLOGRAPHY" HAND-DRAWN HOLOGRAMS
I've stumbled across a technique for drawing holograms directly upon a plastic plate by hand. It sounds impossible, but I've been sitting on the livingroom sofa making holographic images of floating polyhedra, words, 3D starfields, opaque objects, etc. No laser, no isolation table, no darkroom, no expensive film plates. This takes nothing more than a compass and some scraps of plexiglas. Too cool, if I say so myself!
Obtain a small piece of acrylic plastic and a good, non-wobbly set of "dividers" (a compass with two points.) I used a $10 compass from an art supply store and replaced the pencil lead with the supplied metal point. The compass must be the type with an adjusting screw to set the spacing of the points. Or, you can use a 4-in. piece of wood with a couple of finishing nails driven through it to form a pair of points. For the plastic, a CDROM 'jewel case' works fine.
Next, use a marker to draw a simple pattern such as the letter "V" near the lower edge of the plate. This will be the image that we'll encode onto the surface. Draw your "V" less than 1 in. tall (2cm). Set the spacing of the compass points to a couple of inches. Place one point on the tip of the small "V" at the bottom of the plate, and *gently* drag the other point lightly across the plastic so you make an arc-shaped scratch that looks something like the figure below. This is your first scratch. It helps to tilt the compass so the point trails across the surface and does not dig in or chatter. The scratch should be easily visible, but not extremely deep. The scratch should be dark and polished, not white and dusty. It should show a small highlight when viewed in sunlight or under a pointsource illuminator such as a small, clear light bulb. Now, while keeping the dividers at exactly the same spacing, place the point at a different place on the little "V" and use the other point to make a single circular scratch as before. Do this again and again, ten times or more, each time placing the point on a different spot on the little "V". When completed, the overlapping arc-shaped scratches should look like you've swept a bit of sandpaper across the top of the plastic plate. The little letter "V" should be full of holes made by the other point of the compass. [ Detailed Instructions]
