Hydrogen Hypering HINTS Piece

HYDROGEN HYPERING for ASTROPHOTOGRAPHY

Tech Pan and various color films can by hyper-sensitized by soaking in Forming Gas (8% H2) at an elevated temperature ( typically 40-50 C ) to improved their sensitivity and color balance when used on long astronomical type exposures. See what it does to Tech Pan !
You can purchase hypered film from LUMICON. Many astronomy clubs have set up a club hypering 'pool'. You can purchase hypering equipment from LUMICON. You can purchase Forming Gas or Hydrogen from many welding supply dealers. Forming gas can be special ordered with various H2 concentrations. An H2 concentration of 8-10% is typical for hypering work.
Pure Hydrogen can be used (with great caution ) for the hypering of Technical Pan. HOWEVER, if one wants to hyper color emulsions Forming Gas MUST be used or drastic color shifts will occur.
Tech Pan 35mm can be hypered in the cassette with no noticeable problems.
Tech Pan 120 MUST be unrolled from its paper backing before hypering. The paper should be dried out using silica gel while the film is being hypered. 120 rolls that are hypered while rolled will show marked nonuniformities and can not be optimally processed due to these nonuniformities.
Tech Pan should be hypered to a TOTAL density of about 0.70 - 0.75 in order to be at its peak sensitivity level. Film hypered to the usual recommended density of 0.30 above base are substantially slower.
You can buy a KODAK Step Wedge and use it to estimate film fog densities. This is a very inexpensive option and will allow you to estimate fog density with a fair degree of accuracy.

REPRESENTATIVE HYPERING TIMES:

FILM	HYPERING TIME
KODAK Tech Pan	96 hrs @ 50C FG
KODAK Tech Pan	10 hrs @ 40C H2
FUJI SG 400	24 hrs @ 50C FG
FUJI SG 800	16 hrs @ 50C FG
FUJI G 800 PLUS	12-24 hrs @ 50C FG
KODAK PRO 400 PPF-2	5 hrs @ 50C FG
KODAK MULTI SPEED PJM	12 hrs @ 50C FG
AGFA RS 200	12 hrs @ 40C FG

* --> Exact Times will vary depending on
individual variations in hypering.

Film that is to be hypered should be purged by one of several means before hypering to remove some or all of the water and oxygen that will add to the fog level created during hypering. Fog that is not related to added speed gain results in a degradation away from optimal film speed. Purge and desiccation can be obtained in any of the following methods ( in increasing order of purge quality):
- 24-72 hours in dry air ( using silica gel )
- 24-72 hours in dry nitrogen
- 24-72 hours in low vacuum ( > 1mm pressure ) ( hand pump or inexpensive mechanical pump )
- 6-12 hours in high vacuum (< 25 microns ) ** ( two stage rotary pumps .. avoid diffusion pumps ) ** Films hypered after a high vacuum desiccation will hyper in ~10-20% of the time required for films purged using other methods. Films hypered after a high vacuum purge can also be more optimally hypered due to a lower level of fog induced by film contaminants.
An inexpensive entry level hypering chamber can be made from plain old PVC piping... An really inexpensive temperature control system is described in AMOACP and all the parts can be had at a decent hardware store.
Hydrogen ( or Forming Gas ) Hypering via *ANY* method using ANY equipment is a worthwhile investment of time and effort once you start shooting fainter and fainter objects. While more elaborate and more expensive setups may provide more optimally hypered film and more uniform results, even a system made of PVC pipe will produce *substantial* film speed gains and will produce films that function at 75-85% of films hypered in the most advanced setups.
Tech Pan should be processed for AT LEAST 10 min in D-19 at 20 C ....
You are sacrificing film speed and uniformity if you are processing for less than 10 min. NOTE: IF you are purchasing hypered 120 Tech Pan then you should process for no longer than 4-6 min in D-19 or uneven fogging will be seen.
HC-110 dilution B can be used on Hypered Tech Pan. A processing time of 16 min @ 21 C is useful. Tech Pan that is processed in HC-110B will be slightly ( ~10-15% ) slower than films processed correctly in D-19. TP 2415 processed in HC-110B will have a much longer dynamic range than when processed in D-19. MWP-2 is not recommended for the processing of Tech Pan astro negs. While MWP-2 worked well for old 103a type emulsions, it yields a speed that is about 1/2 of the speed obtainable using either D-19 for > 10 min or HC-110B.
If you live in HUMID areas you should think about keeping your film in a DRY environment during the exposure process and try to keep the film DRY while it is in the camera during a photo session. Keeping the film in a HUMID environment can cause hypered film to lose a substantial fraction of its speed.
If you can not purge your camera with a dry gas or with nitrogen during exposures we suggest you skip a frame between each exposed frame to help minimize non-uniformities created by uneven film desensitizing caused by exposure to moist air.
PROPER AGITATION DURING PROCESSING OF TECH PAN IS CRITICAL ! You should use a gentle near constant agitation technique while processing hypered Tech Pan.

To see another good internet source of information on Hydrogen Hypering be sure to visit Jerry Lodrigus' Home Page and his useful articles on this and other techniques.

See A MANUAL OF ADVANCED CELESTIAL PHOTOGRAPHY
for more comprehensive information on this and other topics of interest for astrophotography. Watch for our next book for a very thorough discussion of Hydrogen Hypersensitization.

-- THIS MATERIAL IS FOR PERSONAL USE ONLY --

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