Don't store XTOL with Dust-Off

Discussion in 'B&W: Film, Paper, Chemistry' started by albada, Apr 2, 2013.

  1. albada

    albada Member

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    You might be tempted to use Dust-Off (or a clone of it) to drive the oxygen out of a partially used bottle of XTOL. Well, I found the gas dissolves into XTOL and makes the XTOL more active. Here are the curves:

    130401-HP5-XTOL-DustOff.jpg

    The bottle was 3/4 full, so only 1/4 was Dust-Off gas. XTOL's pH is unchanged, so Dust-Off is doing something else to the chemistry. And it's probably not what you want. The clone I use says it contains difluoroethane. Rudeofus warned me months ago that this is not inert. I should have heeded his warning.

    Mark Overton
     
  2. chriscrawfordphoto

    chriscrawfordphoto Member

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    There used to be a canned gas sold by Beseler and others that was made for this purpose. I think it used nitrogen or CO2.
     
  3. Newt_on_Swings

    Newt_on_Swings Member

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    If you go to a restaurant supply store you can get food grade co2 or better yet food grade nitrogen if it's available. For the co2 they have them in the small metal cartridges (same style as the ones you use in bb guns) that are used for making whipped cream or rapid infusing of herbs and spices in liquids.
     
  4. AgX

    AgX Member

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    Difluoroethane should be as inert as those banned predecessors used as preservative gas for photochemistries.

    And... what did you use? Dust-Off or a that clone?? I'm puzzled.

    The Content of Dust-Off is stated as a mixture containing 60-100% Difluoroethane.
     
    Last edited by a moderator: Apr 2, 2013
  5. Athiril

    Athiril Subscriber

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    Nitrous Oxide is used for making whipped cream. CO2 is for Soda iirc.
     
  6. bdial

    bdial Subscriber

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    CO2 is not inert either, at least not for this purpose. It will decrease the PH.

    There is a product called "bloxygen" which is nitrogen and argon gas, it's sold by some paint suppliers and woodworking suppliers for preserving paints and other finishes. It's expensive, but seems to work.

    Another possibility is to search CL for someone selling a nitrogen cylinder.
     
  7. paul_c5x4

    paul_c5x4 Subscriber

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    You can also get miniature gas bottles for MIG/TIG welding (try your local auto accessory shop). The usual gas is CO2, but pure argon is available.

    One thing to watch for - Whilst the bottles are claimed to be self sealing, they will leak gas slowly, so if you infrequently use one, chances are it will be empty.
     
  8. timhenrion

    timhenrion Member

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    I use Bloxygen. Its an argon aerosol designed for this purpose (inert gas blanket).
     
  9. Bundesphotograph

    Bundesphotograph Member

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  10. EdoNork

    EdoNork Member

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    I use butane-propane from rechargable lighters.
     
  11. Mainecoonmaniac

    Mainecoonmaniac Subscriber

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    I use my old can of Beseler developer preservative. It's gonna run out. What was that? May I substitute Co2? I have a big tank of it for my water carbonator. Will it acidify developer?
     
  12. Sal Santamaura

    Sal Santamaura Member

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    I don't, nor do I use any other gas. Instead, I've purchased these bottles:


    They're glass with teflon-lined caps. After mixing five liters of XTOL (using distilled water), I fill 20 of the bottles to their tops, then cap securely. No oxygen is in or can enter the bottles. Each one constitutes a single film development run and is used in its entirety at one time. XTOL does develop a white, filimentary precipitate after a while, even when it was mixed using distilled water, but pouring through a coffee filter eliminates that very easily. I've used XTOL stored this way for a year with no difference between exposure or contrast indices of the resulting negatives compared to those developed with freshly mixed XTOL.

    A one-time, lifetime investment. No squeezing, no gas, no marbles, no fuss, no muss. :D
     
  13. AgX

    AgX Member

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  15. Alan Johnson

    Alan Johnson Subscriber

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    Tetenal Protectan Spray, from the label on the can:
    Propane 20-40% ,n-Butane > 60%

    Sometimes I use gas intended for a blowtorch, from the label:
    Propane 30% , Butane 70%.

    The Propane and Butane mixture should be inert, Tetenal Protectan Spray has been used for very many years.
     
  16. Bruce Osgood

    Bruce Osgood Membership Council Council

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    I use the same idea with amber 4 Oz bottles. The caps I selected have a nipple in them to displace the few drops of Xtol at sealing. I bought mine from US Plastics. They actually hold about 4-1/2 Oz when filled so a bottle will deliver 9 Oz of 1:2, just right for 4, 4X5 negs (80 sq ") at a time.
     
  17. gliderbee

    gliderbee Member

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  18. michael_r

    michael_r Subscriber

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    Funny how based on everything Mark (albada) has been doing in his research/development of an XTOL clone over the past several months one could simply conclude XTOL is a relatively finicky, non-robust formula for a general purpose developer (despite excellent image characteristics).
     
  19. Bruce Osgood

    Bruce Osgood Membership Council Council

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    I think it dates back further than Marks' entry. The origins of the developer is one of inconsistency and rapid failure when using the 1 Ltr package. A robust and straightforward developer it is but there is the lingering fear that my next batch might fail or go up in flames :wink:. Marks entry is most welcome and when finally refined will be a delight and comfortable alternative to Kodak's if only for the smaller amount of concentrate needed in-house.
     
  20. Newt_on_Swings

    Newt_on_Swings Member

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    Ah I always thought dust off was just CO2 compressed in a can, now that I am looking at a can of the stuff (dust destroyer from staples) it does state that there is difluoroethane in it. Doesn't say the percentage though, and it also contains a bitterant too. I personally dont use these products to fill up the empty space in a bottle, I usually optimize my developing routine to use up a whole bottle of stock solution (I separate them out to 1L bottles) or if I cant use it all up I squeeze the air out (burping the bottle) before I seal it. Since I only use plastic bottles this is possible, but can see why this product would be helpful if using glass bottles. I have also read of people using clean glass marbles to displace the air space, or separating liquid contents from the air with floating lids in larger tanks.

    This finding could be useful though no? If someone would want to boost the activity of the developer without increasing the temperature, this could be a way for extra push processing without having to worry about the emulsion in a hotter/warmer developer. You could stick the end of the dust off can into the developer and bubble it in, or maybe fill half a bottle with it and the developer and shake it in? Maybe there is too much variation in the off the shelf products or even in the absorption rates for this to work well though.
     
  21. albada

    albada Member

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    My goal with the concentrate is to eliminate the "I hopes". As in, "I hope this XTOL is still good, because it's 7 months old." Or, "I hope it's okay because I used Protectan but did I use enough to drive out all oxygen." The concentrate changes colour as it deteriorates, so you know and don't have to say "I hope". Finally, "I hope these bits of precipitate don't put spots on my negs." Sal mentioned that last issue, and I get that precipitate in every batch of XTOL. I'm surprised Kodak allowed a product to ship that does that.

    I like Sal and Bruce's idea of storing in a bunch of little one-shot-sized bottles. Eliminates the air-issue altogether.

    Newt_on_swings: Why don't you sell Dust-Off as "XTOL Supercharger"? Nothing like turning a problem into a feature and making money on it! :smile:

    Mark Overton
     
  22. johara

    johara Member

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    I'd like someone with a developer chemistry background to comment on why Dust-Off or similar products might affect the activity of XTOL. It's not obvious to me why the main ingredient would (but I'm not a chemist). OTOH the manufacturer isn't obligated to list every ingredient on the label, so who knows what's in there. (Note-- I've used Dust-Off to preserve XTOL for years and have not noticed any problems with it, but I use it to make pictures, not exposure/density curves.)

    I can second the commenter who advised against using CO2. That will tend to acidify the developer (if in a water solution), which is not what we want.

    I believe that dry nitrogen has been sold in aerosol-type cans for preserving partially-consumed bottles of wine, whatever those are. Maybe that is still available. Nitrogen is quite inert at room temperature. Though it wasn't a cheap as Dust-Off, as I recall.
     
  23. EdSawyer

    EdSawyer Member

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    Nitrogen from a gas supply place will be the cheapest vs. Argon or something like that. Find a good welding supply place and a 25lb tank will last forever. A single-stage regulator should handle bringing it down to 4-5psi or so.

    I have a welding tank like this but it's filled currently with an argon/co2 mix (75/25) so I need a pure nitrogen tank too probably.
     
  24. Mainecoonmaniac

    Mainecoonmaniac Subscriber

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  25. AgX

    AgX Member

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    The problem I have with Nitrogen high-pressure tanks is that over here they have to be opened and examined after a while. If one buys a large one to save on the refills, it easily can be that before even the first refill it has to go to technical examination.
    Yes, we Germans...
     
  26. Ashfaque

    Ashfaque Member

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    I like the bladder thingy - will try that if and when I try X-TOL. Another cheap and hassle free option is butane gas (lighter fuel). It is keeping my SPUR developers (HRX, Acurol-N) quite fresh.

    Bests,

    Ashfaque