developer chemistry for green sensitive plates

rzeheb · Post by **rzeheb** » Wed Mar 18, 2009 11:43 pm

I've been using JD-2 developer on VRP-M plates (from Integraf) to develop both transmission and reflection holograms created using 532 nm light. The Holography Handbook (Unterseher) lists a number of different options for developer chemicals. However, the Handbook is (understandably) focused mostly on HeNe lasers and red-sensitive emulsions. One of the developers suggested in the Handbook, for use with reflection holograms only, utilizes pyrogallol (solution A) and sodium carbonate (solution B). Does anyone know if this developer will work with green-sensitive emulsions such as the VRP-M plates? If so, how well does it perform compared with JD-2? Also, why would it make any difference if you are using the developer for transmission or reflection holograms? After all, the emulsion is still the same.
Ron

Colin Kaminski · Post by **Colin Kaminski** » Fri Mar 20, 2009 3:00 am

When Fred wrote that book the biggest concern for transmision holograms was low noise. The biggest concern for reflection holograms was for diffraction efficiency. At the time it was common to have different processes for both. Now we have some pretty good processes for low noise and high diffraction efficiency so many people use the same process for each one. If you can afford it get Hanz Bjelkhagen's book. It is one of the best books I have found on processing.

Konrad · Post by **Konrad** » Fri Mar 20, 2009 10:33 am

The best chemistry for VRP-M (and PFG-01) is CW-C2 or SM-6 developer and PBU-Amidol bleach for both reflection and transmission holograms. Also Ferric EDTA is great bleach for reflection, but transmission holograms has more scatter/noise (especially VRP-M)

Ed Wesly · Post by **Ed Wesly** » Fri Mar 20, 2009 12:14 pm

It sounds like the classic PyroChrome developer and it should work fine. The only time that I have seen that formula not work well was when Agfa listened to some "expert" and produced emulsions harder than their normal, and since this developer hardens the gelatin as it develops (pyrogallol is a tanning developer, you will notice a stain in the emulsion not unlike that of tanned leather) it couldn't penetrate deep into the emulsion, making not so bright holograms.

A long time ago in the dark ages of holo-chemistry it was thought that there should be different ways of developing for transmission and reflection holos, but all schemes work well enough with the correct exposure, development times and beam balance ratio.

rzeheb · Post by **rzeheb** » Sat Mar 21, 2009 5:10 pm

Thank you, one and all, for the replies, suggestions, and information! I suppose that in some way it's the steepness of the learning curve that keeps me exited and interested. Once it gets routine I get bored and move on to something else. With all the variables involved in this hobby and the fact that I am "Mcguivering(sp?)" virtually every part of my setup in my basement, I clearly have decades of excitement ahead of me! BTW, all you color holographers are obviously gods and goddesses.