Making Hologenic Objects
Choosing or making a model for a hologram is one of the most important tasks.
- Pick a reflective object.
- Pick an object that is diffuse.
- Pick an object you can hold still.
- Pick an object that will not rock.
Making Your Own Objects
There are many materials that work well for making your own objects. Any sculpting skills you have are well used in holography.
- Keep in mind that the object will be brighter if it is more reflective.
- Diffuse objects randomize the polarization and can add to the fog level.
- Highly reflective objects can cause local places on the film that overload the dynamic range of the recording. (Burn out)
- Very bright spots need to be kept from the film plane when making H2 copies.
You can laminate a transparency to a piece of glass and place it behind the scene and light it from behind.
If you live near a large library there are old drawings and etchings in old books that have an expired copyright. These can be scanned and output onto a transparency. Once laminated to a piece of glass for stability, they can add interest to a scene.
Lighting holography objects is very similiar to lighting a photograph of the same object. Any good book on lighting for photography can be useful for holography. If you want hard shadows use the light straight from a spatial filter. If you want soft shadows or fill light pass an object beam through a diffuser. The size of the spot on the diffuser is a good judge of how diffuse the light will be.
The main object beam will define all of the shadows present and is called the "Key Light" in photography. It can be straight from a spatial filter or it can be diffused slightly. Ground glass or opal glass can be sued for different effects. This light is often coming from in front, above and to the side of the object.
From the other side a dimmer, more diffused light can be used. This is called the "Fill Light". This light serves to fill the shadows to reduce their contrast.
Light can be brought from below and behind the object (remember that the film should not be able to see the light source directly) and is called "Back Light". Back light works well for objects that are transparent or have a fine structure that diffracts light well. Hair is a good example.
Painting your Model
In doing research I have found that Cadmium Yellow reflects 514 excellently while minimally reflecting 457. Cobalt Blue reflects excellently 457 while minimally reflecting 514. And Titanium White reflects both 514 and 457 equally as excellent.