hypersensitization

[k_wakamatsu]

Hello everyone.

I'm searching for how to hypersensitize my BWfilm.

some sites said I need to take a hypering chamber or make it myself.

 

but I'm not mechanically inclined, you know.

 

Does somebody know to hypering without such special equipment?

 

tell me anything.

 

Thank you.

[lex_jenkins]

Some say this can be done using any ordinary processing tank with a reasonably tight fitting lid.

 

The danger is that gas pressure may cause the lid to pop off or, in the most extreme case, rupture the tank.

[chris_waller]

It depends which type of hypering you want to attempt. Peroxide hypering can be done in a developing tank as Lex says. Mercury hypering can be done in a sealed glass container (e.g. a dessicating jar) - but mercury is intensely poisonous. Gas hypering using hydrogen needs, I believe, to be done under high pressure.

[paul a. roid]

first I thought this post was a joke - then I <a href="http://www.atscope.com.au/

astrophoto.html" target="#">googled this</a> <br>

(all the way at the bottom, just before the pic)<br>

doesn't sound like it's easily done at home...<p>

kool stuff tho since I'm having a hard time with long<br>

time pinhole exposures - gotta google some more ;)

[nikos peri]

You used to be able to get complete gas hypering kits from Lumicon... they since went under, and reemerged, so not sure about their product lineup but couldn't immediately find it. On the other hand, it appears they are still selling hypered film, in case you don't want to DIY.<p>

Hydrogen gas forming needs to be done under pressure.

[nikos peri]

Yeah... it looks like they no longer carry that stuff. But you should be able to find it around, as film-users in astrophotography are dropping like flies. In any case, <a href="http://64.233.183.104/search?q=cache:acjEer7xTnIJ:www.lumicon.com/3hype.htm+Film+gas+hypering+kit&hl=en&client=firefox-a">this is what it would look like.</a>

[pat bunn]

Contact Lumicon. They sell Hydrogen gas hypering kits and the gas.

 

You can order the gas at your local welding supply store. It is 8% hydrogen and the remainder nitrogen. It is called forming gas and is used for treating film and also in the semi-conductor industry.

 

I have a homemade hypering chamber and a large tank of forming gas. the gas was $112. You can rent the tank for $4.50 or so a month.

The chamber is a 3" diameter 1/4" aluminum tube with O Ring seals.

It has a cable type heater wrapped around the outside and a thermostat controller.

 

The process requires placing the film in the chamber and drawing a vacuum, then filling with gas and drawing another vacuum. This is done several times to remove all the water. Then the tank is pressurized with forming gas at 3-5 PSI and then heated to 140 degrees F or so and left for 24-48 hours to bake.

 

Lumicon also sells hypered film, although some films remain in a hypered condition for only a week or so. The best B and W film for hypering is Technical Pan.

 

A search on the net will have quite a bit of information.

[melvin_bramley]

I don't think that the gas would rupture a tank; but using, heated, hydrogen peroxide does build up enough pressure to "pop" the top off a Paterson tank ( & hence defeat the process).I have not yet had success with this process but have seen published results that would make it a worth while effort.The secret is to retain the tank pressure to "boil" off the hydrogen peroxide.BTW the results I saw was of 400 film pushed to 3200 with no loss of image quality.The same process can be applied to E6 slide film. Hmmm I must give it another try!

[lex_jenkins]

BTW, I've tried the warmed (not heated) hydrogen peroxide in a tank trick. I couldn't see any difference in my tests. I went back to more conventional pushing with reliable speed enhancing developers.

 

However enough astrophotographers have reported successfully hypering their films that it must be possible to do so.

[reuben_c]

(All typos mine; I do not advise doing any of this unless you understand the risks, and accept all liability for your actions. This is posted strictly for historical and educational purposes.)

<p>

<blockquote>From Chapter VI, Desensitizers and Hypersensitizers, <i>Darkroom

 

Handbook and Formulary</i>, by Morris Germain, quoted under Fair Use

 

doctrine.

<p>

<hr><b>Hypersensitizers</b><br>

Several wet and dry methods of hypersensitization have been used over

 

a period of years, but the technique in handling them has been such

 

that amateurs often ruined film or suffered distress from the ammonia

 

fumes which were employed. By far the best method of all and the most

 

popular in use today is the new mercury vapor treatment.

<p>

The essential procedure is to place the film in n air-and light-tight

 

container along with 8 to 10 grains of metallic mercury. The mercury

 

must be placed in a small glass or non-metallic container. Be careful

 

not to spill the mercury or let it com in contact with the film.

 

Treatment is approximately 36 hours for loose film and about one week

 

for tightly spooled or wrapped material. Other salient information is

 

best given by quoting the summary of the research report on the <i>New

 

Method For Dry Hypersensitizing of Photographic Emulsions,</i> by F,

 

Dersch and H. Durr, Agfa Ansco.

<p>

<blockquote>

<hr>

"Hypersensitization by mercury vapor increases the speed of

 

photographic negative emulsions about 50 to 150 percent, depending

 

upon the emulsions used for the treatment. The important features of

 

this method that make it superior to the well known

 

wet-hypersensitizing methods are:<br> (1) The film does ot have to be

 

put through a bathing process and then dried. (2) The mercury vapors

 

are active also upon tightly wound spools of film, the sensitizing

 

effect being uniformly spread over the whole length (e.g., of a

 

1000-foot roll of 35-mm. motion picture film). If sufficient time is

 

available for hypersensitizing, the films need not even be removed

 

from their original wrappers, as the mercury vapors diffuse

 

sufficiently through the wrapping material. (3) The increase of

 

sensitivity is general throughout the range of wavelength of light to

 

which the film was originally sensitive. (4) Not only can unexposed

 

film be hypersensitized by this method, but it is also possible to

 

intensify the latent image with mercury vapors. (5) The stability of

 

the film is not permanently affected, although the increase in speed

 

is gradually lost over a period of four weeks of aging. The clearness,

 

however, remains the same, and may even improve somewhat. By a second

 

treatment with mercury vapor the hypersensitization can be renewed in

 

a film that has recovered from previous hypersensitizing."

<hr>

</blockquote>

<p>

For one who likes to experiment purely for the love of

 

experimentation, time in hypersensitizing will be well spent and much

 

knowledge can be accumulated. When getting the picture is the main

 

thing, hypersensitizing should be avoid if possible and resorted to

 

only when absolutely necessary.<hr></blockquote>

[rowland_mowrey]

Anyone who uses mercury is as mad as a hatter, and that is where the expression came from. Felting of hats used mercury and the felters of hats gradually went insane from mercury vapor.

 

Even a tiny spill of mercury will vaporize throughout your room and even your home. It can cause severe fogging if film is left in contact with it.

 

Free mercury metal is a forbidden substance in all photographic manufacturing facilities for this reason. If there is ever a spill of mercury or its salts, a special decontamination squad is dispatched to clean it up with a wet vacuum with a micro filter.

 

Mercury salts were used at one time as addenda to films. They were eliminated in the 60s as part of the pollution abatement programs at EK.

 

Ron Mowrey

[Dave Luttmann]

Check some of the books written by Jack Newton & Philip Teece. Jack decribes making a hypering chamber for less than a bottle of Scotch. I made one with a pressure valve built right in that I used with forming gas and a hand pump for years. Probably had 300 rolls of tech pan and 100 rolls of Kodak PPF thru it before I switched to CCD imaging.

 

Another option is to hypersensitize using a silver nitrate mixture. Forming gas sensitization can last for a good month in your freezer, Silver Nitrate hypering needs to be processed within a few hours.

 

ALl the best.

[k_wakamatsu]

surprised for such many good answers.

 

I want to try "hydrogen peroxide hypering" .

 

Thanks you all.