Test for possible age-fogging in RA4 paper

Discussion in 'Color: Film, Paper, and Chemistry' started by pentaxuser, Jun 6, 2011.

  1. pentaxuser

    pentaxuser Subscriber

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    I have been trying to recalibrate a Colorstar 3000 analyser and noticed that the unexposed part of the test strip used to calibrate neutral grey was, when processed, coming out an ivory/cream colour and not a pure white. While unexposed but fully processed Kodak Supra Endura may not be as white as say Ilford MG it looked quite ivory/cream.

    I performed what I think is the right test tonight which was to remove a piece in the total darkness and process in Kodak dev, stop and blix, wash and dry. Then I removed a second piece and just blixed, washed and dry.

    On examination there was a clear difference. The blixed only piece was a bright white whereas the fully processed piece was an ivory/cream colour

    My understanding is that if there is no age-fogging both pieces should be the same colour. Is this correct?

    If I have age-fogged paper to the extent described aove what effect would this have on a print from a neg other than white appearing ivory? I haven't got that far as I am still trying to calibrate for neutral grey.

    Is the box a throw away item now?

    Thanks

    pentaxuser
     
  2. Photo Engineer

    Photo Engineer Subscriber

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    You will always see some color in the Dmin of RA4 paper developed in RA4 developer. It is inevitable. There is always some tiny amount of fog in any photomaterial that shows up with development.

    To prove this, you can take some MGIV paper and fix and wash, and another piece and Develop, stop, fix and wash. You will see a difference there as well. It may only show up with a Densitometer, but it is there.

    PE
     
  3. pentaxuser

    pentaxuser Subscriber

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    Thanks PE. The difference in the fully processed and blixed only strips are more than marginal. They are as clear as day. A user on another forum said that his processed Kodak RA4 paper was bright white in unexposed areas whereas mine isn't by any stretch of the imagination.

    I did some research last night and came across a thread I had started then on the Colorstar in June 2006 I think I must have bought the Supra about then or maybe early the next year so it is more than 4 years old and has always been stored in my darkroom at ambient temp.

    pentaxuser
     
  4. brucemuir

    brucemuir Member

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    My guess for what it is worth was...
    there would be some fog due to the process of development.

    Good to know I am learning a few things thanks to PE and this great place!
     
  5. Photo Engineer

    Photo Engineer Subscriber

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    Well, the dmin depends on process chemistry and darkroom lighting to some extent. The paper and developer contain optical brighteners which can whiten up paper visually if there is enough or if there is UV illumination. Some kits have no brightener. So, the answer is "it depends". Lack of brightener causes a significant yellowing.

    Also, 5 years is not much keeping but that again depends on the conditions. So, one answer does not fit all!

    PE
     
  6. RPC

    RPC Member

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    I had this same problem a while back with paper that had a cream colored D-min and with this paper I had trouble getting good color balance, for example skin tones were especially difficult to balance. It was suspect from the get-go, as I had purchased it off ebay from an individual who claimed it was refrigerated. So I switched to paper I knew was fresh and the problem went away. I think it is safe to say that in your case and mine the problem is expired paper. Don't use it!

    RPC
     
  7. pentaxuser

    pentaxuser Subscriber

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    RPC. It is a question of what constitutes "white" and as you say the effects on colour balance. If the effect was simply that white parts of the print had a slight creamy look then this might be OK but if skin tones can't be made to look right then this becomes very noticeable.

    One pack as far as I can recall was purchased from new and I think PE is suggesting that 4-5 years isn't that old. The other pack was obtained via a seller but someone whom I trust when he says that it was properly stored. He estimates it may be up to 6 years old but the box has a higher CAT number than the purchase from new box. Does this means that it isn't as old?

    PE As I have the boxes how easy is it to establish manufacture date and how do I go about it. I am in the U.K.?

    Thanks

    pentaxuser
     
  8. Photo Engineer

    Photo Engineer Subscriber

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    Sorry, IDK the current numbering system.

    PE
     
  9. RPC

    RPC Member

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    If 4-5 year old paper had been stored at freezer temperatures I would trust it but if it has been stored at "ambient" temperatures which I presume you mean room temperature I would not.

    I suggest you just try making some prints with negs you have printed before and compare color quality. In my case the paper was quite cream color for whatever reason and my thinking is that there was crossover, but in your case may not be as severe.

    RPC
     
  10. jm94

    jm94 Member

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    i had age-old tetenal RA4 paper come out with a very yellowed background (whites were very yellowed, the borders were also yellowed) but this only occoured after development and not if i just blixed a sheet... age old paper which was stored in a fridge (not a freezer) but i still keep it for when i want an artistic effect :smile: