41 replies to this topic

[Ionian]

Does anyone gas their film these days? If so has the gas or procedure change?

[Avgvstvs]

Like hypered? I haven't really heard about it since the 1980's.

There maybe some old hands still at it

[Michael Covington]

Forming gas still exists, as it is used in industry for various applications that need to exclude air and oxygen from something (film hypering is just one of many).  I am not conversant with further details.

At the end of the film era, I discussed with a physicist the feasibility of hypering with deuterium (heavy hydrogen, which is not radioactive and apparently not extremely expensive).  When used to passivate (air-proof) semiconductors during manufacturing, it apparently sticks better than plain hydrogen.

One other thing to note is that today's films already have a lot less reciprocity failure than earlier ones, and may not *need* hydrogen hypering.  At the end of the film era, I was shooting unhypered Ektachrome.  Today's Ektachrome 100 and Kodak Ektar films appear, from their published specs, to be even better, as does Fuji Acros black-and-white film.

Preflashing remains a viable way of "hypering" film in a slightly different way, if it would otherwise be severely underexposed.  At least bump it up into the linear region of its sensitivity.

Digital is so much better that I stopped doing any of this when I got a DSLR.

Edited by Michael Covington, 15 March 2022 - 05:46 PM.

[Todd N]

Hypering principles are the same. But each film must be separately tested and refined for what is optimal. Many films may have been reformulated over the years and may not responded to hypering as they once did. I've tested most of the B&W films and technical films on the market going back more than five years. Most films don't respond to H2 hypering, the few that do, it is insignificant and the handful of them that have some significant enhancement, it is not tremendous. Fomapan 400 has had the best response but it is extremely grainy and it's enhancement from H2 hypering is moderate. I do plan on using it to see what results I can get for H-aplha imaging. It's likely off the shelf color film would outperform it for H-alpha imaging. Fuji Acros 100 II performs out of the box so well that it is the default choice for B&W broad spectrum imaging; Doesn't have significant H-alpha sensitivity. I wouldn't go out the way to try hypering film. Fuji Acros and many color films from Kodak perform extremely well for astrophotography as it is.

[TxStars]

I have not found a current film worth hypering, tho I do have a couple films that need to be tested..

 

Charles

[astro744]

The first time I used hypered Tech Pan 2415, I overexposed the Sagittarius Star Cloud!  This in the late 1980s.

 

Lumicon used to sell a hypering kit which I always wanted to get but never did.  I think the forming gas they sold was 80/20 Hydrogen/Nitrogen as pure hydrogen probably required special storage precautions for home use.

 

I found a film vendor that sold hypered film and I just bought it when needed and used it as soon as possible.  I don’t recall if it came packed in dry ice but it sure worked.  I didn’t enjoy astrophotography as much and pursued visual astronomy but occasionally took some photos using either prime focus or eyepiece projection (for planets) through the telescope usually with non-hypered film.

 

 

[Ionian]

I have heard of preflashing but never tried it or know of anyone that has. Can you elaborate?

[Michael Covington]

Simply pre-expose the film so it will be lightly fogged (visibly not quite unexposed) when developed.  This helps start it responding to light.  

I never got very far with this, but I can imagine a lot of ways to do it.  It's easiest if your camera permits double exposures.  Then what you do is take a very underexposed flat frame (the way digital astrophotographers do, but severely underexposed), then expose your astrophoto on top of that.

[BillHarris]

I used a lot of hypered 2415 back in the day but took a break in the late '90s, and when I returned 2415 was not available. I still have a Lumicon hypering tank and a couple of bottles of forming gas.
I've slowly slithered back to star photos, but honestly, just enjoy viewing and making observations (something I was too busy for, before). Currently I dabble in the Moon and planets with a C8.

[Helge F.]

There is a Kodak’s research paper from the late 90s early 2000s (which I can’t for the life of me find right now), that discusses a lot of the rites and traditions surrounding gas hypering.

It turns out that vacuum chamber treatment is perhaps not beneficial with today’s film.
It did make sense with very long exposures back in the day.
But it really only slows film down with modern emulsions.
It dries out the gelatine, and thereby crushes the halide crystals.

You get 80 to 150% of the benefit, by simply doing a long treatment in ambient temperature normal pressure hydrogen. Something which is quite achievable by even a rank amateur.

Even a stop of extra speed at normal quality would be welcome.

Edited by Helge F., 27 January 2023 - 10:06 AM.

[SMigol]

HelgeF

 

Thank you for this note about normal pressure H soak.

 

It's a personal goal of mine to build a 4x5 tank and try it.  

[Todd N]

There is a Kodak’s research paper from the late 90s early 2000s (which I can’t for the life of me find right now), that discusses a lot of the rites and traditions surrounding gas hypering.

It turns out that vacuum chamber treatment is perhaps not beneficial with today’s film.
It did make sense with very long exposures back in the day.
But it really only slows film down with modern emulsions.
It dries out the gelatine, and thereby crushes the halide crystals.

You get 80 to 150% of the benefit, by simply doing a long treatment in ambient temperature normal pressure hydrogen. Something which is quite achievable by even a rank amateur.

Even a stop of extra speed at normal quality would be welcome.

 

I've dug up many papers on Kodak and hypering archived from the Harvard-Astrophysics Data System, but I don't recall coming across such a paper; That would be an interesting read. And as it turns out, that has been my experience in test hypering modern B&W films. Too high temperature(40C), especially with Kodak films didn't work well. IIRC, it created lower contrast. My preliminary test for films is hypering at room temperature for two days just to see if there is a significant response. Modern Kodak films response to hypering is low-moderate and since Acros came back, its performance is way superior right out of the box. Ages ago, I came across a webpage from an astrophotographer who was a chemist and he hypered his Techpan at room temp in pure H2 for six or seven days. Since he worked in a lab I bet it was a cold 68F. He reported it worked just as well and held up to being stored cold in the freezer. 

[SMigol]

This is wonderful news to me.  

 

Not having to worry about pressurizing hydrogen and vacuuming the chamber makes the testing easier.

[Todd N]

This is wonderful news to me.  

 

Not having to worry about pressurizing hydrogen and vacuuming the chamber makes the testing easier.

 

Clarification: I would presume(unless I'm wrong) what is meant is to not subject the film to a prolong vacuum to desiccate the film, which probably was ineffective anyways unless one could achieve a high vacuum which required high end lab equipment to pull out molecular water from the emulsion; Beyond what a hand pump or vacuum pump could do. I would think you would still want to purge and vacuum pump the chamber to eliminate water and especially oxygen from the hypering process. They will fog film the higher the temperature e.g. warmer summer days. It would also be a good idea to hyper at a plus one, two or so PSI since if the pressure gauge reads zero accordingly then you will know you have a leak.

[TxStars]

I have always pulled first vacuum then let the film sit in nitrogen @14psi for 24hrs before hypering.

Hypering done @14psi for xx hours @70f

After hypering the film is placed in a bag with nitrogen till ready to use it..

Edited by TxStars, 27 January 2023 - 07:31 PM.

[Michael Covington]

What I suspect is that after hydrogen hypering was discovered, Kodak and others discovered (and kept secret) other ways to produce a similar effect in the sensitization process itself.  I know that newer films coming out in the 1990s had markedly less reciprocity failure than their predecessors.

[Helge F.]

AFAIR the most important thing is getting rid of oxygen. And water is of course oxygenating.
But drying the film out is not a good idea if we are looking at sub 1 hour (again AFAIR) exposures, because it shrinks the gelatin.
Hydrogen hypering works kind of like the two electron sensitization in Vision3 and Portra film. But could probably work in addition/accumulatively to it.

Edited by Helge F., 30 January 2023 - 09:30 AM.

[TxStars]

I never had an issue with the film being too dry, but I have seen others create issues.

The most interesting is static discharge when advancing 35mm film rapidly.

This created a lightning strike image on several frames..

[xonefs]

I've dug up many papers on Kodak and hypering archived from the Harvard-Astrophysics Data System, but I don't recall coming across such a paper; That would be an interesting read. And as it turns out, that has been my experience in test hypering modern B&W films. Too high temperature(40C), especially with Kodak films didn't work well. IIRC, it created lower contrast. My preliminary test for films is hypering at room temperature for two days just to see if there is a significant response. Modern Kodak films response to hypering is low-moderate and since Acros came back, its performance is way superior right out of the box. Ages ago, I came across a webpage from an astrophotographer who was a chemist and he hypered his Techpan at room temp in pure H2 for six or seven days. Since he worked in a lab I bet it was a cold 68F. He reported it worked just as well and held up to being stored cold in the freezer. 

 

 

So I have a bulk roll of tech pan on the way... I would like to try hypering

 

What's my best bet for a vacuum tank to try this? not adding heat could simplify things. is there any real danger of pure h2 if the tank is kept outside? I could keep it outside during 82* FL days for a few days. 

[Todd N]

So I have a bulk roll of tech pan on the way... I would like to try hypering

 

What's my best bet for a vacuum tank to try this? not adding heat could simplify things. is there any real danger of pure h2 if the tank is kept outside? I could keep it outside during 82* FL days for a few days. 

 

You need a vacuum tank that can hold higher pressure. Before I was able to acquire a Lumicon hypering tank I couldn't find the equivalent. I was considering getting a custom tank made and that would have been pricy.

See Abbess Instruments:  https://abbess.com/

 

The Lumicon lid has a sealing rubber O-ring with wingnut screws to tighten it down. I had not been able to find similar on the market. Here is an old webpage on making a hyper chamber out of PVC pipe:

http://www.starrynig...es/vac_tank.htm

 

I tried making something like this but didn't perfect it. It obviously is meant to hyper Techpan in cassette. The recommendations for hypering in cassette are a bit different: higher pressure, but I think that can be ignored. If you go this route, I would suggest hyping only half a roll or less in a cassette, that's about 2 1/2 ft. One is not likely to use that many frames in a single night anyway. 

 

You will also need a cannister of Nitrogen to repeatably flush the tank; No point in wasting hydrogen this way. I would buy two calibration tanks of N2 to one H2. I have both tanks hooked up to the same line with a T-branch so, I'm not introducing small amounts of outside air into the system. DO NOT use an electric vacuum pump to evacuate a chamber of pure hydrogen! This could cause the H2 to go boom. I first use a hand pump(manual vacuum pump for car breaks) to remove about half the chamber and then fill with N2 and then I use the electric vacuum pump to fully evacuate. This is to be done outside. The small amount of H2 is not an immediate danger but you wouldn't want to have it accumulate inside with repeated attempts and breath it in by chance. For a small chamber a hand pump can suffice.  I would store the tank inside or garage. I store mine inside my home, no biggy. The valves on my tanks have never leaked on their own that I can tell. A small calibration tank like 34 Liters is not enough to cause an explosion in a normal size room. It takes a 4% concentration and then ignite it to have an explosion. For a 1000 sq. ft. room I estimated that would take about half the volume of a scuba tank. 

[Todd N]

 

 

I going to retry an experiment I did years ago. That post I mention where a chemist used to hyper rolls of techpan at his work, I recall he stated he used a desiccating bell. That would require lower pressure than atmosphere to maintain the seal. I bought a simple vacuum chamber that is used for degassing and tried this once and it didn't seem to work all that well. And since I had the Lumicon chamber there wasn't a need to pursue this. I may have not hypered  long enough. I will try this again and report back. It should take about a week or so. 

[xonefs]

Thank you.

 

Do you have photos of what the lumicon tank looks like? that would be ideal though obviously hard to find. 

[Todd N]

Thank you.

 

Do you have photos of what the lumicon tank looks like? that would be ideal though obviously hard to find. 

No personal photos of my chamber. Here is an add for the same large hypering chamber that will do up to 4x5 format. 

https://astromart.co...it-for-4x5-film

[xonefs]

are there any color negative films that hyper well? has anyone tried hypering Ektar?

[Joe F Gafford]

The little old blue tank Lumicon had is not legally refillable. It took forming gas, a mixture of 5% hydrogen and 95% nitrogen. You had to send the tank to Lumicon to get a it refilled or replaced. Check with your local gasses supply. 

 

Joe