Hints and Kinks
This is a collection of simple tips and techniques worth sharing.
Rotating Polarization with Mirrors
This image is self explanitory on how to rotate the polarization of the laser beam with two front surface steerable mirrors. This was taken directly from Kaveh's Thesis with his permission.
I have successfully killed bad fogging on Slavich plates (without also killing the photosensitivity) by soaking them for exactly 60 seconds in a solution of:
- 20 g Ferric EDTA
- 10 g KBr
- Water to make 1,000 ml
This solution keeps for years. Ferric EDTA is ethylenediaminetetraacetic acid ferric sodium salt. What amazed me was that the photosensitivity of the plates did not drop noticeably afterwards without my needing to resensitise them in say 2% ascorbic acid (vitamin C) at pH ~6.
adapted from the thread http://holoforum.org/forum/viewtopic.php?f=9&t=215
PBU (Phillips - Bjelkhagen Ultimate) bleach makes a good film defogger
- 10 g Potassium persulfate
- 10 g Sodium bisulfate (or citric acid)
- 20 g Potassium bromite
- 1 g Cupric bromide
- 1 g Amidol (or Metol)
To use it as defogging solution, pH must be raised first, otherwise the sensitizing dyes will be deactivated. (This is true at least for the PFG-03C dyes.) Diluted it 1:10 parts water, then raise the pH to 5.6 by adding drops of 10% sodium hydroxide. Soak the plates for 1 minute in the solution, then rinse and allow to dry.
Effect of Overexposure
adapted from a post by Joe Farina, http://holoforum.org/forum/viewtopic.php?f=7&t=652
The graph is from Lasers and Holography by Mehta and Rampal, 1993. It was reprinted from a paper by Chang and Leonard, "Dichromated gelatin for the fabrication of holographic optical elements," Applied Optics, 1979.
adapted from a post by manalokos, http://holoforum.org/forum/viewtopic.php?f=7&t=138