Changes

For a holographic test, the beam needs to be almost but not exactly perpendicular to the plate to make the traditional test with polished coins. With the beam shuttered, the coins are placed on top of the recording plate preferably on the glass side of the plate, and left for at least 10 minutes to settle. A newly made gelatin film may contract by a nanometre or two during exposure while it is thus sandwiched between the 2 glass sheets but simple coin holograms can still be obtainable because the coin to “emulsion” distance should stay the same at least for most of the emulsion attached to the plate’s glass. The important point about this test is to see how quickly the exposed hologram takes to darken in a developer such as TJ1 (see below). This glass table top system is excellent for making holograms in an unstable environment because the plate and object can “ride the storm” together.