The Slavich film substrate is slightly different to that used on the old Agfa products and as such should be treated, particularly at large format, with different techniques.
Slavich film products are currently made with 150 micron tri-acetate plastic film. This material is deformed less easily than that used with Agfa and can be rolled flatter both as a consequence of the material used and of the fact that the film is thinner than Agfa.
For small format holography you may treat the Slavich film identically to Agfa. All techniques of film holding that worked with Agfa are useable with the Slavich material.
For larger formats (20x30cm and above), however, you will find that just mounting the Slavich film be tween two glass plates does not ensure adequate film flatness. This is because the thinner TAC film is less rigid than the Agfa product. Consequently you must use one of several techniques of temporary mounting when exposing a Slavich film hologram.
One of the most effective ways of temporary hologram mounting for all types of hologram (with both CW and pulsed lasers) is to use the liquid Tetrachloroethylene which may be found in any dry-cleaning laundry. The technique is as follows:
- Clean a glass plate for mounting your film on and place this plate horizontally in a well-ventilated area. The plate should be slightly bigger than the actual film.
- Fill a medical syringe (with no needle – volume depending on the size of film to be mounted) and place a strip of fluid parallel and near to one edge of the glass plate.
- Apply the film to the glass plate with a mounting roller making sure that you evacuate all the bubbles.
- Now simply use the glass plate as you would a normal glass holographic plate.
- After exposure and latensification (if appropriate) simply peel off your film and develop as usual. Any residual liquid on the film will evaporate and in any case will not affect development.
Note that you must pay attention to ventilation when using this technique
Another technique which is useful for rainbow copies is the use of the PENSTICK mounting foil made by MOLCO in the USA. This foil is essentially a double-sided adhesive that can be removed and reused.
Yet another technique is to use permanent mounting before exposure using a non-birefringent double-sided adhesive film such as produced by FLEXCON, again in the USA.
With larger format holograms you will find that the Slavich material does need to be mounted to a rigid flat substrate such as a glass or plastic sheet. Whereas, with Agfa, you could just about get away for bigger formats (i.e. 30x40cm) by simply putting the film between two glasses, with Slavich you can’t! However, you’ll find that the end result ,when you do mount the hologram properly with a double-sided film, is very similar.