Frequently asked questions

The green (514nm) sensitivity is about 5x worse than the red (633nm) and 442nm is around 1.5 x better than the green.

No, unfortunately there is no equivalent material to Agfa 8E75 for use with deep-red pulsed radiation.

PFG-01

Whether your pulsed laser is appropriate for Holography or not is a highly complex question and depends on the detailed construction of your laser. You should hence contact an expert in holography lasers. The recommended emulsion for Neodymium lasers is VRP-M. This emulsion is sensitive from nanosecond pulse to CW laser emission.

PFG-01 and PFG-03M (Red laser) and PFG-03C (Red or Green Lasers).

The quality will be poor as VRP-M requires high carrier modulation to achieve good diffraction efficiency. Since the Denisyuk technique is typical of small carrier modulation the brightness of the final reflection hologram will be disappointing. For Denisyuk type holograms with green laser radiation you should use PFG-03C or PFG-04.

Yes.

Pretty much all the qualities will be better as the PFG-04 emulsion is grainless and over twice as thick as VRP-M. Hence the image will be brighter, clearer and you�ll be able to see into the hologram to a larger distance.

Yes, no problem. Many holographers are using this technique. You may use either PFG-01 or PFG-03M. Just check that your YAG laser is designed for Holography.

The VRP-M film has a very high energy density threshold and as such may be used easily for the production and copying of rainbow master holograms of large and small size.

You will need a Neodymium YAG or YLF frequency-doubled holography laser. Those lasers are produced only by Geola. The recommended holography material for Neodymium pulsed lasers is VRP-M.

It is extremely doubtful that an industrial laser will be of the slightest use for holography.

Provisionally the answer is yes. Its just necessary to check that your output emission lies within the sensitivity envelope of PFG-01 or VRP-M. Check the Spectral sensitivity curves for this once you know what dye you are going to use.

Yes, if you want to obtain blue to ultra-violet colour of final hologram. TEA must be used for pre-treatment of the emulsion.

Yes.

There is no smallest size. Even with 1mW you can make excellent holograms. All depends on the exposure time - less energy of your laser - longer exposure time.

The practical lifetime of VRP/VRP-M plates and film at 20/25 degrees C and low humidity is more than 5 years. Rolls of film can last even longer reaching greater than 10 years. At +4 degrees C the lifetime for plates and sheet film is around 10 years.

The practical lifetime of PFG-01 plates at 20/25 degrees C is around 3 years. At 4 degrees C it is rather more although how much more has not yet been tested. Sheet film behaves similarly to the plates and rolls are again much longer-lived.

The practical lifetime of PFG-03M/C plates when stored in plastic boxes at +4 degrees C is till 12 months. Rolls of film at +4 C last more than 1.5 years.

PFG-04 practically lasts 24 months at +4C and 12 months at +20 C.

Practically the optimum storage temperature for all materials is 4 to 8 degrees C at low humidity. Negative temperatures are NOT desirable and should always be avoided when possible although short durations (during transport for instance) are not critical as long as the plates/film are not subsequently warmed up in a humid environment.

Note that rolls of film that have been stored for many years frequently have a 30 mm - 50mm stripe of damaged film at each extremity along their length. This is due to the interaction with air. Hence if your aim is to keep film products for very long times it is better to stock large width rolls.

Very high humidity (>85%) should always be avoided as they will degrade the lifetime rapidly. Medium to low humidity are acceptable with low humidity being optimal. Temperatures above 80 Degrees C lead to the PFG-03 material becoming sensitive to the polarization of light. Also exposure to such high temperatures will produce a gradual decrease in sensitivity. Short exposures of all materials to temperatures up to 50 Degrees C will not affect performance or greatly reduce the lifetime. Transport of the materials through hot countries is generally not a problem.

We accept larger orders for non-standard size plates.

Once a sheet is taken off the roll its lifetime is reduced to for about twice time.

Not particularly.

The exposure forms in the holographic emulsion the very faint record (latent image) of the exposed object. To make this latent image visible - the emulsion has to be developed and bleached.

Developing: The crystals (grains) of silver bromide in the emulsion are reduced to black metallic silver.

First Wash in Water: This removes all traces of developer.

Bleaching: This process oxidizes the silver image to silver bromide, the emulsion now becoming transparent again with a slightly milky appearance.

Second Wash in Water: This removes all traces of bleach.

Drying: Removes water from developed and bleached emulsion structure and the hologram becomes visible when illuminated by spot light source.

Note: Ultrafine grain emulsions needs an additional operation - the hardening.
Hardening hardens the soft emulsion that it becomes suitable for further processing

Yes.

Yes.

One can develop about 1.5-2 m2 of holographic emulsion in one liter of SM-6 developer and several times more this amount of emulsion can be bleached in same bleach solution.

The quantities given here are the approximate quantities you need to realize about 400 holograms 30x40cm

Supply:
One can find the chemistry from : Sigma-Aldrich, Fluka or Prolabo
Go to these web sites to find a local distributor or contact directly the supplier.
Agfa, Sigma-Aldrich, Prolabo, Fluka, are registered trademarks of their owner.

You can keep SM-6 during 2-3 days in a closed bottle if it was not used. But if you start to work, better to use the same solution during one day only. The bleach is not so delicate. It is possible to use the same solution for up to 3-4 days.

This depends on the developer but usually this must be a light to deep brown. Initially the plates should be transparent/blue. Note that for VRP/M/PFG-01 the plates before development are transparent and after they must become deep gray to black.

Very important, as moisture destroys the image. If you do not seal your hologram then your image will quickly disappear.

You would need a pulsed laser providing Single Longitudinal Mode and coherence length not less than several meters. You can purchase such laser from Geola uab - price range 39,500 - 69,000 EURO. The holographic material suitable for this application is VRP-M.

Yes, TEA may be used exactly as previously employed with the Agfa material.

No, it is not necessary for your case. In the worst case you will find that you need a little more radiation than expected for the optimum exposure. Latensification just improves the sensitivity in certain regimes. There are some CW cases where latensification will economize your laser radiation but usually it is not nearly to the extent observed with pulsed radiation.

Drying is a sensitive process. We recommend drying by soaking in soapy water. 1 capful of Agepon (or equivalent) per 1 litre of water works well. Be very careful to clean your film or plate meticulously before putting it in the soapy water. Any residual deposit on the emulsion can lead to severe problems. Certain chemistries will indeed produce non-soluble precipitates that need to be cleaned off by gentle and thorough wiping with a leather automobile cloth whilst the film is soaking in an (additional) bath of soapy water. Do not let any chemicals get into your final water bath as this must be completely pure. Make sure that you overdo it on the washing between processing baths and be careful you are not polluting the baths by picking up chemicals from one bath and putting them into another with your gloves or fingers (note- strong warning for your health: use gloves). Finally make sure that you take the film or plate out from the final bath slowly and in a controlled manner. The soap must be well dissolved but there should be very few bubbles. When you put the plate to dry in air, choose a quiet place that has low dust levels. Higher humidity when drying leads to taking longer to dry but to a better result.

VRP-M is stable in oil so there is no problem in using oil-bath type film holders. After exposure and latensification you should use a simple household detergent with water to remove the oil before processing.