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Randy Moe
8-Sep-2015, 17:55
As some know I am trying Gas Burst development.

I am not a chemist and wonder about degradation of developer and fixer from Gas Burst operations. Advice, thoughts?
I observe most call the process Gas Burst, not N2 Gas Burst and all systems I have researched have 2 pressure systems, one N2 and one compressed air.


Specifically, I am using compressed air with one shot Rodinal @1/100 10 minutes. 55-10 second off, 1 second on cycles. It seems to me that one shot developer does not need N2 gas as the developer will last the cycle.

I am more concerned about TF5 Fixer as I reuse it from a 4 gallon tank and test with film for clear speed before each use. Plenty of scrap X-Ray around here.

Will my rather complete aeration of TF5 with compressed air degrade it quickly? Am I contaminating or weakening my storage fixer tank reserve? I use 1 gallon out of 4 and dump it back in.

I suppose I will find out empirically.

Will I get longer usage from TF5 or any fixer by using N2 for Gas Burst?

In the future I may go to a developer replenishment system. Will I really need N2 for Gas Burst. Or not?

Theorists and user input highly desired.

Thanks in advance.

Michael Wesik
9-Sep-2015, 06:32
Hi Randy,

Alistair Inglis is a wonderful fellow who makes gas burst systems and he may be of some help to you: http://www.alistairinglis.com/

Best,

Michael

Peter De Smidt
9-Sep-2015, 06:59
Randy, I've never heard of fixer being affected by oxygen. In color processing Blix (Bleach + Fix) actually requires oxygenation in order to work effectively. I'm not even close to being a chemist, though. You might ask Ron Mowry (Photo Engineer) over at Apug. Lynn Jones, who's a member here, might also know. He was responsible for setting up gas burst systems for developing movie film. I'll send an email off to an acquaintance of mine. He was a project manager in the BW division at Kodak.

Randy Moe
9-Sep-2015, 13:25
Hi Randy,

Alistair Inglis is a wonderful fellow who makes gas burst systems and he may be of some help to you: http://www.alistairinglis.com/

Best,

Michael

I hesitate to ask Alistair anything, especially his recomended processes.

I respect his IP rights and if he wanted to share more, he could on his website.

I am not his customer. I am DIY, relying on members here and historical data as I find it.

I'm in the ballpark, I just need to learn my game better.

Randy Moe
9-Sep-2015, 13:26
Randy, I've never heard of fixer being affected by oxygen. In color processing Blix (Bleach + Fix) actually requires oxygenation in order to work effectively. I'm not even close to being a chemist, though. You might ask Ron Mowry (Photo Engineer) over at Apug. Lynn Jones, who's a member here, might also know. He was responsible for setting up gas burst systems for developing movie film. I'll send an email off to an acquaintance of mine. He was a project manager in the BW division at Kodak.

Thx. I need to speak to my chemist in Chicago.

Bob Salomon
9-Sep-2015, 13:55
Randy, I've never heard of fixer being affected by oxygen. In color processing Blix (Bleach + Fix) actually requires oxygenation in order to work effectively. I'm not even close to being a chemist, though. You might ask Ron Mowry (Photo Engineer) over at Apug. Lynn Jones, who's a member here, might also know. He was responsible for setting up gas burst systems for developing movie film. I'll send an email off to an acquaintance of mine. He was a project manager in the BW division at Kodak.

Afraid Lynn is no longer with us.

Michael Wesik
9-Sep-2015, 14:32
I hesitate to ask Alistair anything, especially his recomended processes.

I respect his IP rights and if he wanted to share more, he could on his website.

I am not his customer. I am DIY, relying on members here and historical data as I find it.

I'm in the ballpark, I just need to learn my game better.

Totally your prerogative.

When I used gas burst it was recommended by several people to use nitrogen and not compressed air. I can't remember the explanation.

Peter De Smidt
9-Sep-2015, 14:34
Afraid Lynn is no longer with us.

I'm very sorry to hear that. Bob, thanks for letting me know.

Tony Lakin
9-Sep-2015, 14:38
It's nitrogen for developers and air for bleach and fix.

Michael R
9-Sep-2015, 17:15
Thiosulfates are more stable in air than say developing agents, but they do oxidize. This is one reason why even neutral (eg TF-5) and alkaline fixers contain sulfite to scavenge oxygen. In general, plain air is not the best idea for gas burst agitation in a B&W process. If you want maximum longevity out of your TF-5 with a re-use regimen, nitrogen would be the way to go. Alternatively if you stick with air, test your fixer at regular intervals. Using air will accelerate oxidation, but how much faster, we don't know. It may or may not make a meaningful difference in how long you normally run a batch of TF-5. All you can do is monitor it.

Hope this helps.

Randy Moe
9-Sep-2015, 17:39
Thiosulfates are more stable in air than say developing agents, but they do oxidize. This is one reason why even neutral (eg TF-5) and alkaline fixers contain sulfite to scavenge oxygen. In general, plain air is not the best idea for gas burst agitation in a B&W process. If you want maximum longevity out of your TF-5 with a re-use regimen, nitrogen would be the way to go. Alternatively if you stick with air, test your fixer at regular intervals. Using air will accelerate oxidation, but how much faster, we don't know. It may or may not make a meaningful difference in how long you normally run a batch of TF-5. All you can do is monitor it.

Hope this helps.

Yes, that helps.

Thank you!

Harold_4074
9-Sep-2015, 21:24
Michael R has it right; the thiosulfate will react with oxygen, at a rate partly determined by the rest of the formulation. The sulfite, as an oxygen scavenger, will convert to sulfate. It also stabilizes the thiosulfate against acidity, which is why pure thiosulfate solution will precipitate sulfur on contact with the carbon dioxide in the air. Presumably, there is more going on in TF-5 than these simple reactions; I don't know the formula and in fact still use TF-4, which has a recommended storage life and tray life which are probably based on oxygen permeation of the bottle and solution respectively.

Gas burst agitation creates a lot of air/liquid surface area, and the turbulence will pretty much eliminate concentration gradients, so whatever can happen to fixer in contact with air will happen a lot faster in a burst system than in tanks or even trays.

My worry would be that the degradation would not be gradual enough to trigger the "double the initial clearing time" test until suddenly a batch of film comes out stained, grainy, or otherwise compromised. Exhaustion of things like stabilizers, plasticizers and inhibitors can behave that way.

Randy Moe
9-Sep-2015, 23:19
Michael R has it right; the thiosulfate will react with oxygen, at a rate partly determined by the rest of the formulation. The sulfite, as an oxygen scavenger, will convert to sulfate. It also stabilizes the thiosulfate against acidity, which is why pure thiosulfate solution will precipitate sulfur on contact with the carbon dioxide in the air. Presumably, there is more going on in TF-5 than these simple reactions; I don't know the formula and in fact still use TF-4, which has a recommended storage life and tray life which are probably based on oxygen permeation of the bottle and solution respectively.

Gas burst agitation creates a lot of air/liquid surface area, and the turbulence will pretty much eliminate concentration gradients, so whatever can happen to fixer in contact with air will happen a lot faster in a burst system than in tanks or even trays.

My worry would be that the degradation would not be gradual enough to trigger the "double the initial clearing time" test until suddenly a batch of film comes out stained, grainy, or otherwise compromised. Exhaustion of things like stabilizers, plasticizers and inhibitors can behave that way.

Thanks Harold,

I will be getting N2 in 2 weeks and will start using it on TF5 right away. Heretofore I was counting sheets and replacing fixer at a set schedule. I am now certain TF5 or any fixer will degrade faster with Air Gas Burst.

Then I will need to consider how to test in a discernible way the efficacy of N2 and Air on one shot Rodinal. That may be a poor quest.

If N2 cost over time is low enough, I will simply use N2 for all processes. The air compressor simply got me running sooner.

Mark Sampson
10-Sep-2015, 08:32
I won't contradict the chemists, but in the lab where I worked at Kodak we used nitrogen for the developer and air for stop bath and fixer. We (naturally) followed the recommendations engineered (and published) by our colleagues at Kodak Research Labs across the river. I never saw fixer degrade faster than normal- at least it always lasted until the 'square-inches of film' limit, when we replaced the stop bath and fix. All EK products of course...
As I recall, (this was c.1985), gas-burst systems were meant for full-strength, replenished developers and lots of film; not diluted, one-shot methods. But this may make no difference in practice.

Jim Noel
10-Sep-2015, 09:51
"As I recall, (this was c.1985), gas-burst systems were meant for full-strength, replenished developers and lots of film; not diluted, one-shot methods."
Correct. At the college we used N burst with D-23 on a replenishment basis, and air for the fixer. The D-23 was used for a full semester at which time I recovered it for use in total development when maximum increase in overall density and contrast was needed. Since the average usage was on the order of 1200-1500 sheets of 4x5 per month, the D-23 lasted well, but the fixer had to be changed sometimes every other day.
In the final years of using the system, we did not use gas burst for fixing, but had students remove film from hangers and fix in trays. This eliminated problems with under-fixed negatives.

Harold_4074
10-Sep-2015, 12:42
I never saw fixer degrade faster than normal- at least it always lasted until the 'square-inches of film' limit

That sounds entirely reasonable, since there is probably a good margin of safety built into the limit. My guess is that you were using either Kodak Fixer or Kodak Rapid Fixer (or the bulk equivalents--wasn't there something like Ektafix sold in boxed bags?) which was rather different from the TF series of fixers. Anything with sodium thiosulfate to which sulfuric acid is going to be added is probably going to need a lot more sulfite than a "neutral" fixer, which could play into the oxidation characteristics.

This thread has me wondering if the old formulas for fixer test solution are usable with the TF series, and if not, is there a formula that is? My suspicion is that the modern vendors of photographic chemicals, with the possible exception of Ilford, do not do quite as much research and quality control as the old Kodak did, and the published capacities may be extremely conservative. I think that the shelf life of TF4 concentrate is given as something like six months, which seems awfully short, and I know from experience that three-year-old bottles clear film in under sixty seconds, just like new stuff does.

Michael Kadillak
10-Sep-2015, 17:01
If there is one thing I learned in this LF/ULF photographic pursuit of mine is that gas burst is a time tested art form that does not need to be reinvented. Use N2 for development and adhere to what took Kodak decades to perfect - period! When I wrote the Gas Burst Article in View Camera years ago it was after a full two years of attempting to follow Gordon Hutchings Book of Pyro conclusions that were flat out WRONG. I did NOT need special tanks and hangers much to my dismay in believing that Gordon had done his homework which he simply did not. When I gained access to the Kodak Gas Burst article which I have shared freely on this forum the sky opened up. I am up to the largest N2 tank that one can purchase without going into the lease program.

Randy Moe
10-Sep-2015, 17:18
Michael, I am not trying to reinvent anything and have not read Gordon Hutchings Book of Pyro.

Once I found the Kodak data I immediately moved in that direction. My Gas Burst set points are identical, but my developer is not. I may go to a replenishment developer system in the future.

I will be using N2 exclusively asap, 2 weeks.

I am curious about your developer. Are you using the same batch for long periods or mixing fresh often? Will you share what you currently do?

Your View Camera Magazine post was key in sending me down this path. There is very little data available. So I am searching for all I can find.

Thank you.

Duolab123
10-Sep-2015, 19:48
I have my copy of Kodak pamphlet E-57, revision 9-70. Says what all of you good folks are saying nitrogen for developer air for the rest. I actually have a BS in Chemistry, not that that makes me any kind of expert. The thing that occurs to me is that if you are using a one shot developer I would think you could very easily get by with air. If Rodinal survives use in Jobo drums with reels, roll or sheet film reels it should survive air bubbles for one cycle.
Also Kodak recommended for B&W 1 sec bursts, 6 times a minute. With Ektachrome in E-3 they say 2 seconds only once per minute.

Having said this our atmosphere is loaded with Oxygen. It amazes me how little air left in a partially full bottle of developer will spoil it. I don't keep partial bottles of stock solutions any more I have a bunch of PET bottles 2,4,8,16,32 oz and fill them to the very top. I have kept XTOL stock for over a year and never had a problem. I just dump the bottle into a beaker then fill the bottle with DI water to make 1:1 Xtol, have used this method for at least 15 years.

Harold_4074
10-Sep-2015, 20:04
I have my copy of Kodak pamphlet E-57, revision 9-70. Says what all of you good folks are saying nitrogen for developer air for the rest.

I'm pretty sure that TF5 was not the fixer of choice in 1970; the chemistry of thiosulfates hasn't changed, but the formulation of fixers has. I wouldn't say that air is bad for agitating fixer, but unless you are talking about an acid, hardening fixer based on sodium thiosulfate, I wouldn't say that it is necessarily innocuous.

Also, there is theoretically a big difference between bubbling fully oxygenated air through developer and putting the same developer into a sealed container with a small amount of air for the same amount of time.

Some testing would be needed to settle the issue one way or the other, but life is short and nitrogen is cheap...

Michael Kadillak
10-Sep-2015, 20:16
I primarily use Pyrocat HD in highly dilute semi stand mode at this stage in my gaseous burst process. I spend considerable time with Alistair Inglis assisting him dial in his tanks in larger formats. Conventional developers just don't get me enough RPM's in print mode.


Michael, I am not trying to reinvent anything and have not read Gordon Hutchings Book of Pyro.

Once I found the Kodak data I immediately moved in that direction. My Gas Burst set points are identical, but my developer is not. I may go to a replenishment developer system in the future.

I will be using N2 exclusively asap, 2 weeks.

I am curious about your developer. Are you using the same batch for long periods or mixing fresh often? Will you share what you currently do?

Your View Camera Magazine post was key in sending me down this path. There is very little data available. So I am searching for all I can find.

Thank you.

analoguey
10-Sep-2015, 20:22
Went through another couple of threads on the topic, post Michael's reply. Loads of Info here, but I get the feeling that even with all that, this is something where experience is needed to actually make (practical) sense of the info. While I'm currently in the middle of rejigging my enlarger light source, (once that's sorted out) this will be the next thing I would attempt.

One question though - does it need only high volume processing for the Gas burst process to pay off?

Michael Kadillak
11-Sep-2015, 06:47
Went through another couple of threads on the topic, post Michael's reply. Loads of Info here, but I get the feeling that even with all that, this is something where experience is needed to actually make (practical) sense of the info. While I'm currently in the middle of rejigging my enlarger light source, (once that's sorted out) this will be the next thing I would attempt.

One question though - does it need only high volume processing for the Gas burst process to pay off?

I say that it is not necessary to only have high volume of processing to make the process pay off. One should take into the consideration a number of other issues into proper context. My particular views on this subject center around both simplicity and repeatability of the process taking out as many variables as possible. With gas burst there is really only one moving part and that is the solenoid valve opening and closing allowing the N2 (or air) into the plenum base. No rotating drums, manual tray or even brush agitation, or dipping and dunking. Once I confirmed that I could use pyrocat in this process I was all in. The Reduced Agitation Process (primarily controlling extreme + and - development) is highly effective in using minimal volumes of pyrocat as well as small quantities of N2. Quite honestly the challenge is not in the process but in finding older 3.5 gallon tanks, plenum/hanger combinations and solenoid valve/timer controller panels. I was fortunate to have scrounged up a number while the getting was good but most of this equipment was likely tossed out when it was not selling. Having the ability to process a large batch is great but not necessary since even smaller process runs make sense.

I did run across an article on the development of Xtol where Kodak used replenishing techniques in their testing and was going to explore and refine this technique further, but found a point where I was pleased at what conclusions I was able to arrive at after a long frustrating journey and pulled off the side of the road to get some results in the done column. I will hunt up that article and post it if anyone is interested. I will continue to reiterate the need for safe recharging of air into the darkroom when using N2 gas burst so a buildup of this inert gas does not fill the darkroom and create an oxygen deprivation working environment. Please BE SAFE!.

Duolab123
11-Sep-2015, 17:47
I sure agree about the Nitrogen is cheap we use these same types of cylinders of Nitrogen at work to pressurize 250 gallon tanks of polyurethane chemicals. They last a long time, If you are using this setup for 30 minutes a day Developer and fix I would venture 1 cylinder would last a year. TF-5 is 58% ammonium Thiosulfate, ie Kodak Rapid fix, it's been this way since G. Eastman was running the show. Kodak F-5 stinks, Kodak F-6 doesn't stink as bad. Both use good old sodium thiosulfate same. Ammonium Thiosulfate is used in I would say almost every liquid fixer formula out there. And I would say not to be rude but fixer chemistry has not changed in over a century, THERE! This outta make everyone go nuts:-) Just my opinion not very humble:) Don't shoot the messenger
Peace!

Jac@stafford.net
11-Sep-2015, 18:30
Regarding the solenoid that releases N2, a super strong current sapper is not necessary.
Electrical hydraulic and water valves can be like the one in your clothes washer: it does
not make a single powerful pull or push of a valve, but vibrates instead.
.