We generally recommend first-time holographers use holographic plates instead of holographic film. That's because holographic film sheets can easily move during exposure. If the holographic film bends or moves even one thousandth of an inch during exposure, your hologram will not turn out. Instead, you will see gray blotches or irregular-shaped rings when you try to view the hologram. In more severe cases, your film sheet will come out completely gray.
The good news is that you can minimize such movement and thus still succeed in making satisfactory holograms with holographic film. For less experienced holographers, one such way for is by sandwiching the holographic film sheet between two glass plates.
2. Creating a Simple Film Holder
When using holographic film sheets, it is critical that you ensure the film remains motionless during exposure. To do this, you can create a film holder. Simply sandwich the holographic film sheet between two plates of clear glass and then hold the plates together firmly with two metal spring-type clamps (our Budget Holokit includes these items). Though not a perfect solution for minimizing movement, it is the simplest way for beginners.
There are several important procedures you should follow when using holographic film sheets with your film holder. These are outlined below. As for the remaining steps such as setting up, exposing, and developing your hologram, these are similar to those used when working with holographic plates (see our article "Simple Holography").
Remove Air from Film Holder
Even small amounts of air trapped next to the holographic film sheet can allow the film to move. Thus, we must remove pockets of air by squeezing the film tightly between the glass plates. You can use a pair of wooden blocks or flat hardbound books to press hard and evenly against the glass-film sandwich. Do so for 10 seconds or more.
Face Emulsion Side of Holographic Film Sheet Toward the Subject
The emulsion is the light-sensitive coating that is applied to the film backing material. For best results, face this emulsion side toward the subject of your hologram. This enables light to reach the emulsion without being degraded as it travels through the backing of the holographic film sheet. You can tell which side of the film has the emulsion because it feels sticky when touched by a most finger.
Wait Five Minutes Before Exposing the Film
Even with the holographic film sandwiched in the film holder, the film (and the holder itself) may shift during exposure. Thus, for best results, wait approximately five minutes between the time you finish setting up your secured film holder and subject to the time you actually expose the film to the laser. This will allow both your holder and the film inside it to settle.
In exposing holographic film or plates, always plan ahead to minimize vibration around your lab and your emulsion, laser, and subject. Walking around your lab, loud sounds from a stereo, air flow from a vent, and even your breath are examples of things that cause vibrations that may ruin your hologram.