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  1. #1
    Dave Krueger's Avatar
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    Why are liquid developers packaged in HDPE?

    Since photographic developers are so sensitive to oxidation, why do manufacturers almost always package them in ordinary HDPE bottles? Why not PETE bottles instead?

    Finally, how important is it to keep developers away from light? I'm assuming it must not be that important if most developers are not packaged by the manufacturers in dark bottles. I'm wondering if the recommendation to use brown bottles is nothing more than a myth. I rather like using clear PETE because you can easily see discoloration.

    Does anyone have answers for these two questions over which I have been agonizing for years? Ok, well not actually agonizing, but certainly curious about.

    -Dave

  2. #2
    Ian Grant's Avatar
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    Packaging regulations as some chemistry is hazardous. If you look at household bleaches etc they aren't in PET either nor are any otherhazardous liquids.

    PET bottles aren't safe and I've had them break down in about 18 months maybe 2 years, in an accident they are far more likely to split/break.

    Ian

  3. #3
    Dave Krueger's Avatar
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    Thanks, Ian.

    I suspected it might have something to do with shock resistance. I use gallon size PETE bottles for Dektol and the sides are sucked in as the developer absorbs the oxygen from the air inside. DOing that repeatedly is going to eventually result in cracking.

    But what about the dark versus non-dark containers? Myth or reality?

  4. #4
    AgX
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    I assume PET bottles non-corroded by their content as unbreakable under practical lab situations.

    There are even PET-based bottles with enhanced oxigen barrier. (In general there is a variety of PET resins for bottle-making.

    Furthermore there are co-polymer bottles on the market that yield greater oxygen barrier with PE-bottles.

  5. #5
    Dave Krueger's Avatar
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    PET seems to be more brittle than HDPE, so it might be more prone to break if you drop it. I use them in one gallon size which makes them pretty heavy when full.

    I also have some HDPE bottles that have a nylon interior coating that is supposed to improve the barrier qualities, but I'm not sure exactly how that plays with photo chemicals. Nylon's permeability can decrease in water, or so I've read. On the other hand I have some Xtol stored in them that was mixed up in July of 2011 and it worked fine as of last weekend.

  6. #6
    AgX
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    I have a lot of usage of 2L PET single-use bottles filled with water whilst hiking. They often fell about a 1.5m in various states of filling and never broke. There were kinks in the worst case.

  7. #7

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    I just ordered and received (haven't used yet) a quart of Legacypro eco-pro paper developer, which has been reported to be ascorbic based and therefore sensitive to oxidation. It is packaged in a brown PETE bottle and, as delivered, is slightly squeezed in at the side. Apparently, when there's a unique need for an oxygen barrier, PETE is used.

  8. #8
    Ian Grant's Avatar
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    Quote Originally Posted by Sal Santamaura View Post
    Apparently, when there's a unique need for an oxygen barrier, PETE is used.
    That also goes for HDPE, in the case of the Legacy Pro product it's more likely cost in their choice. Ilford and Agfa (and successors) sell their liquid ascorbic based devlopers in HDPE

    Ian

  9. #9

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    Quote Originally Posted by Sal Santamaura View Post
    ...Apparently, when there's a unique need for an oxygen barrier, PETE is used.
    Quote Originally Posted by Ian Grant View Post
    That also goes for HDPE, in the case of the Legacy Pro product it's more likely cost in their choice. Ilford and Agfa (and successors) sell their liquid ascorbic based devlopers in HDPE...
    According to this

    PET passes less than 1/8 the oxygen that HDPE does. I'm not sure what relative costs are, but, given that HDPE is ubiquitous and PET isn't, suspect the latter is more expensive, not less.

  10. #10

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    There are also composite bottles which contain more than one layer of different plastics. Such bottles have better oxygeb blocking than single layer ones. Such composites are included under a SPI code of 7 (the number in the recycle triangle). You often see them used for nutritional drinks where oxygen can cause flavor changes.
    Last edited by Gerald C Koch; 03-19-2013 at 02:26 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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