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  1. #141

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    Naaa that is an argument without any practical merit in THIS context.
    We are not developing color films you know, (most of us) are not printing in the darkroom any more, fewer will in the future.
    We employ a modern gizmo called a scanner. This thing cuts through bot fog and color dyes like a knife in butter.
    It is also fully color sentisive, so we can scan any color we, like and change the colors afterward or even turn the thing into B/W with just one click on a virtual button...

    So this was an answer looking for a good question....

    For your information we come from a running debate on Caffenol, where the guys demand to exchange KBr with iodized table salt, large amounts of it, and accept the acompanying yellow stain as if nothing happened....

  2. #142

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    Practical experience is outside a lab, with no million dollar funding in my book.

    I have worked with quality control in a traditional chemistry based lab for years and know the difference between my old lab workstration and my kitchen bench. Unless you have done both you won't know thge difference....

  3. #143

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    Mark I would NOT worry over the manufacturer changing the formula: I would worry over the SELLER changing his supplier.......

    However that turnsw out to be a small or no problem, in my those changes are accompanied by very literal changes in packaging, literal and very noticeable, and most often with drastic color changes as well.

    Is that a problem? On the conbtrary, it's an opportunity!

    An opportunity for another string of tests, finetuning and improvement. After all the world is supposed to move forward, it will only do so through hard work.

  4. #144
    Photo Engineer's Avatar
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    Well, I have a number of developer and fixer formulas on sale right now that were designed in my home darkroom with no million dollar lab at my disposal. So, I have done both high end and low end.

    I have done lab scale and pilot scale work on emulsions at EK and have replicated them in my home darkroom to the extent that I have duplicated Azo paper (for those still into darkroom printing). And that brings me full circle! what makes you think that a potential blue stain would be uniform? And, what does a non-uniform stain do to a print or a scan? Hmmm?

    So, have fun.

    PE

  5. #145
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    There is an inherent risk in using products "off label" - manufacturers can, and will alter their formulations at any time. Their only responsibilities are to retain the functionality of their product for its stated purpose. MSDS sheets need only list hazardous substances, and even then, the word "proprietary" protects the manufacturer from having to reveal specifics.

    In other words.. proceed at your own risk! It's often the 1% of a "99%" product that causes havoc. Been there, done that.

    What's the point of producing a negative that has to be corrected by means of scanning/software? That's not what I'd call an analog process.
    - Ian

  6. #146

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    Quote Originally Posted by Photo Engineer View Post
    The blue color is a dye. Who cares what color the inside of your car radiator or coolant tubing is? We do care about the color of our film! So, what if the blue colorant or film vehicle changes due to manufacturing changes by the companies involved? The film may end up blue! And, the blue color may change with time and pH as the CO2 in the air changes the pH of the film.

    PE
    Well, the blue color IS a dye, but don't you wash your film after fixing? I do. I wash the film to that extent that if a blue colour shows up in 5 or 10+ years, it isn't because of the dye in the glycol, but from any chemical stored next to the film during that years.

    I would worry a bit less and be happy with what works at the moment. What is going to change tomorrow, next year, or in ten years, we can't do anything with today.
    Your developer formulas may also be worthless in 10 years if the film manufacturers changes the way the emulsion is made.
    If that happens, we have to start over and make a new developer then. If we are afraid of trying things today, we won't have any experience when that happens.

  7. #147
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    I could give you a dye suitable for radiator fluid that you might not be able to wash out of film or that might shift color unpredictably.

    As for films requiring a new developer formulation, not gonna happen. The R&D needed would cost too much in the face of the current market.

    So, remember that I am only suggesting prudence in this and the use or "real" PG or EG and I am only pointing out (along with a few others with chemistry experience) what might happen based on similar experiences.

    My bottom line, expressed many times here, is "use what works for you". Just don't complain if things go wrong. I have spent hours answering PMs or threads here explaining what went wrong. And, sometimes nothing does go wrong.

    PE

  8. #148

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    Quote Originally Posted by Photo Engineer View Post
    I could give you a dye suitable for radiator fluid that you might not be able to wash out of film or that might shift color unpredictably.

    As for films requiring a new developer formulation, not gonna happen. The R&D needed would cost too much in the face of the current market.

    So, remember that I am only suggesting prudence in this and the use or "real" PG or EG and I am only pointing out (along with a few others with chemistry experience) what might happen based on similar experiences.

    My bottom line, expressed many times here, is "use what works for you". Just don't complain if things go wrong. I have spent hours answering PMs or threads here explaining what went wrong. And, sometimes nothing does go wrong.

    PE
    The blue colour used in coolant will wash out. They won't introduce a colour that makes the hands of mechanics permanently blue or any another colour. The colour used in tax-free diesel here in Norway is another story. It won't wash out completely in any way. This to make it possible to detect if a car is run on tax-free diesel sometime in it's lifetime. That to make it possible to wite a fine of several tens of thousand dollars to the present owner.

    The amount of borax already present in the coolant isn't going to dictate the resulting pH in any way. The amounts we introduce is way more so it is of no concern to us.

    I don't like to take negatives aspects into concideraton before they in fact are a reason to rethink. This may occur if we are warned that something is going to happen with the composition of either the film or the glycol we are using, OR when we discover that something has in fact changed.

    I would be more concerned about the keeping qualities of pure propylene glycol. It oxidizes in contact with air,AND is it prone to bacterial growth since it isn't toxic.
    What happens when the developer is attacked by bacteria that eats ascorbic acid or sodium ascorbate? If they produce something that destroys the phenidone it would be just perfect, or not.

    Trond Solem.

  9. #149
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    Well, if PG is so unstable, then how does HC110 keep so well as a syrup?

    If AA is chewed up by bacteria so easily, then how does any PG/AA developer concentrate survive?

    The answer is out there! Bacteria don't like Borate, Sulfite, TEA, DEA etc, etc, etc! And PG is not as unstable as the earlier reference seems to indicate.

    PE

  10. #150

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    Whether or not a particular chemical is toxic to higher life forms is not a good indicator of whether it is toxic to bacteria. There is at least one species of bacteria that metabolize arsenic and another that does so with hydrogen sulfide. To cite only two examples. Bacteria are going to be inhibited by the high osmotic pressure of the developer concentrates and the lack of water.

    Both ethylene glycol and propylene glycol are suitable as solvents for developer concentrates. Unless there is a chance of a human or pet drinking the glycol either one is usuable. Both are quite stable.

    While I am in favor of using pure ethylene or propylene glycol there a places where these chemicals are not readily available. Using antifreeze may be acceptable if someone carefully tests them for the purpose of developer concentrates. Some brands may be better than others.
    Last edited by Gerald C Koch; 12-23-2011 at 04:28 PM. Click to view previous post history.
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

    ~Antoine de Saint-Exupery



 

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