Kodak Portra Black & White Paper, RA-4 / getting heavy magenta cast

Discussion in 'Color: Film, Paper, and Chemistry' started by lhalcong, Feb 18, 2013.

  1. lhalcong

    lhalcong Member

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    I ran acros a box of old expired Kodak Porta Black & White paper, but for $6 bucks I decided to give it a try.
    no matter what I tried , I kept getting a magenta cast while printing a contact sheet. Today I decided to go on and try to print the first picture regardless. I printed a strip of 2 sec steps (2-4-6-8sec) and to my suprise, very good black and white tones. I was happy and found my perfect exposure at F16 for 7 sec. What do I get a horrible and quite heavy magenta cast. So I thought maybe cause I am reusing the developer. So I tried a fresh batch of developer. Horrible magenta cast. I tried changing the exposure to F11-3.5sec just in case (shouldnt matter but I had to try), I get horrible magenta cast. what gives ? what is causing this magenta cast. I originally thought maybe 'cause the paper was expired, but that one test strip came out perfect...
    I duplicated exact temperature, process time and Filter pack I had used during the test trip. nothing,: I get magenta cast. I don't get it ?

    thanks for any ideas.
     
  2. pentaxuser

    pentaxuser Subscriber

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    So just to summarise: You get a magenta cast when contacting all the negs on a contact sheet of paper when presumably using the white light from the enlarger?

    You get a perfect print using a test strip at f16 and 7 secs but the same magenta tone returns when you use the same over all exposure with F11 and 3.5 secs. When doing the test strip did any of the other exposure such as 2,4, 6 secs etc have the magenta cast or were they all free of the cast?

    Everything else about your process was identical with both the magenta cast prints and the perfect prints?

    If all of the above is correct then I don't get it either. Are you sure that it was exactly as I have summarised and is my summary correct?

    Thanks

    pentaxuser
     
  3. cjbecker

    cjbecker Member

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    Yea I dont get it either. Is it the same magenta cast as if you left the paper out in the light for a long period of time?
     
  4. Thomas Bertilsson

    Thomas Bertilsson Subscriber

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    Does the Portra RA-4 paper require color correction like the more normal color RA-4 papers do?
     
  5. pentaxuser

    pentaxuser Subscriber

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    One more question: What were the filtration settings, if any, when doing the contact sheet or was it simply white light and did anything change when doing the test strips? I just cannot work out what had changed to produce a neutral print at f16 and 7 secs and a cast at f11 and 3.5 secs.

    The only changes I can see is that the contact sheet was one sheet, the perfect print test sheet was another sheet and the same exposure print on which the cast re-appeared was a third. So bad sheet, good sheet, bad sheet???? Makes no sense

    We need this OP to read our posts and respond. We can speculate until the cows come home otherwise

    pentaxuser
     
  6. Mike Wilde

    Mike Wilde Member

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    I have a few hundred feet of a 12" roll this suff, long expired languishing in my freezer.

    You can tune the contrast range by tweaking the filitration.
    It is designed to be only moderately filtered if you are exposing a C-41 negative, is the masking in the neg does most of the heavy lifting. +/- 50R off of a base of 50R I seem to recall is how my stuff works now.

    Yes, I get a magenta cast in al image elements, and even a slight one in the all white areas of the print all the time with this stuff. It can suit some images. That is why this stuff came with an expiry date.
    I have not had any sucess gettign rid of this cast.

    I use the paper mostly to catch up on contact printing back logged b&w fnegative filer pages when I otherwise have the ra-4 roller processor fired up to print colur work.
     
  7. lhalcong

    lhalcong Member

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    Here are all the answers:

    - Yes , I was getting a magenta cast when printing contact sheet with white light from the enlarger.
    - I dont get a perfect print when printing for 7sec @ F16 I get a heavy magenta cast.
    - When I did the test strip at 2-4-6-8 sec , I did not get a magenta cast. all steps are free of magenta cast (weird)
    - yes, everything was identical about the prints with cast vs. the strip test without cast. (filter pack had not changed)
    - the piece that I used for the strip was cut from a sheet, when I used the second half of the same sheet I got a magenta cast (so the theory of the one good sheet, several bad sheets also does not hold)
    - your summary is correct.
    - Filter pack was 55M 45Y when I printed the test strip that came out with no color cast. so without changing filtration I printed the full print for 7 sec @ F16. I got the magenta cast... (weird)

    - I did not leave the paper out, guaranteed.

    - yes, the portra Black & White (this is a black and white chromogenic paper) does require filter correction but behaves different than the normal color RA-4 such as endura. I read in publication g4006 that filtration depends on what type of film you are trying to print from. (it has several starting points depending on the film). For my case I was printing from BW400CN which is also a chromogenic black and white C-41 film. So in other words, I was printing from C-41 chromogenic black and white film onto Portra RA-4 also chromogenic black and white. So I used both suggested starting points on the publication. always magenta cast.

    I hope to have answered all the questions. I did further testing last night, I will post the findings later to see if they make sense to anyone.
     
  8. Thomas Bertilsson

    Thomas Bertilsson Subscriber

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    As Mike Wilde has stated above, it is probably a thing of the paper having aged unfavorably.
     
  9. lhalcong

    lhalcong Member

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    Actually to Mike (since you have this expired paper like me) and everyone. I am happy to report that I was able to get rid of the magenta cast. With repeatable results. Actually getting good black and white tones perhaps not as neutral as orthochromatic but within workable results to make the paper usable.

    Please note that no matter what filtration I would use, I was always getting the same heavy deep magenta cast . So I never thought the filtration had to do with the problem as the magenta cast never changed. I am not an expert chemist in anyway so forgive if I don't know what actually solved the problem but here is what I did.

    - I went and read the publication again g-4006 . this is the exert that lighted the bulb in my head.

    Processing conditions may affect the color (hue) ofPORTRA Black & White Paper. You may see a hue changeon the magenta/green axis due to variations in developer tankactivity and pH. Low developer activity and/or pH (typicallysevere oxidation and/or under-replenishment) will cause ashift toward a green hue. High developer activity and/or pH(usually over-replenishment) will cause a shift toward a​
    magenta hue.

    this is what I did as I figured this would lower developer activity... (I dont know how to check or modify pH)

    - pre-wash 3 times until water came out fairly clear.
    - I further diluted the developer by adding more distilled water to the working solution.
    - I further diluted the stop bath , I figured this would reduce the acid.
    - instead of using motor agitation, I did manual rotation (much slower) by hand .
    - and what I believe to be most important; I lowered the developer temperature to 74F increasing the processing time from 45sec to 2 min.

    voila, now every print comes out with no magenta cast, I mean none , zero. no color cast whatsoever. The interesting thing is that when the print would come out with the magenta cast, the stop bath would be dark bluish , but when prints come out without the cast, the stop bath would be pink. I wonder what happens in there....??
     
  10. pentaxuser

    pentaxuser Subscriber

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    Glad you have solved the problem but what seems still inexplicable and may remain that way is why in what I assume to the same timescale i.e. done consecutively you got a neutral print. I had a look at he same Kodak publication and there is nothing even hinting at your steps as a means of curing the problem

    So like you I am still puzzled as to the cause of the problem.

    pentaxuser
     
  11. OzJohn

    OzJohn Member

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    I bought a box of this stuff in 8x10 when it was first released and could never make filters produce any real effect. It always produced a magenta cast - not excessive but annoying. I had a well sorted RA4 processing setup using a roller processor so processing variations were not an issue. In the end I used most of the box for contacts as someone here still does because I thought it was a pretty ordinary B&W paper that was a good idea only in theory. I understand that Kodak, a bit later, released another RA4 chromogenic B&W paper that was better and also one that produced sepia tones. They were only available in rolls and apparently did not last on market very long. OzJohn
     
  12. lhalcong

    lhalcong Member

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    Mike, Since you said you also had this magenta cast you had not been able to get rid of, do you have a way to try the steps I try at your own scale. Is that possible for you ? I am not a chemist or far from me, but I came up with those steps after imagining a way to reduce developer activity... and it worked. In fact if I kept reducing the temperature and agitation, it starting showing a slight cast in the opposite direction.

    Pentaxuser. the clue that I had was; the publication states:

    "Processing conditions may affect the color (hue) ofPORTRA Black & White Paper. You may see a hue change on the magenta/green axis due to variations in developer tank activity and pH. Low developer activity and/or pH (typicallysevere oxidation and/or under-replenishment) will cause ashift toward a green hue. High developer activity and/or pH(usually over-replenishment) will cause a shift toward a magenta hue."

    Tell me if my reasoning makes sense, or just a very lucky shot...
    thx​
     
  13. pentaxuser

    pentaxuser Subscriber

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    Yes I think your reasoning makes absolute sense and I noticed the same section in the Kodak publication. What I was trying to say rather clumsily was:1 Kodak doesn't seem to be helpful about what the user does to lower developer activity, given that this magenta cast may be easy to create. You had to discover this yourself and presumably had to deviate from what Kodak would have said was the correct process which should have produced a neutral print

    2. It is still a mystery why at the first time when the issue arose and without your later changes you did manage to get a neutral print alongside your magenta cast prints.

    For what it is worth I once used the Kodak TCN 400 film and had it commercially developed and printed on RA4 paper and there was a slight but noticeable hint of magenta in some prints. I suspect that there was a hint in all the prints but in some scenes and tones it was almost invisible but somehow none of the prints looked right compared to silver gelatin prints.

    It certainly dissuaded me from bothering with Kodak chromogenic films and RA4 paper for B&W prints again.

    pentaxuser
     
  14. Mike Wilde

    Mike Wilde Member

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    Could be a while until I get to trying your fix, but I will keep it in mind. I have a fuji roller processor, and was printing ra-4 on old royal paper last postcard exchange. Winding off 30 prints, the last ten came out progressively more magenta/purple, paricularly on some where there was known edge fogging.

    So I peeled the processor cover off to check the dev tank temp, and whoa, the thing was up to 45C.

    Turns out I think I now have a flakey set point potentioneter or intermittent solution temperature thermistor.
    I swapped all of the electrolytic caps out of the control board three years ago, so they should not be a problem again yet.

    So yes, even regular RA-4 can go purple if over developed. I will try a more dilute RA-4 for the portra mono stuff next time I have the zing to use it.