Is Rollei Ortho 25 orthochromatic or not?

Discussion in 'B&W: Film, Paper, Chemistry' started by michael_r, Jul 19, 2011.

  1. michael_r

    michael_r Subscriber

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    Rollei ATO 2.1 seems clear enough. But when you read about Rollei Ortho 25, the literature says it is panchromatic sensitized. Is it ortho or not?

    And while we're at it, do you have to use a red safelight with a film like ATO 2.1 or other ortho films, or can you use a regular OC filter. I'd like to avoid buying a red filter if possible, but not sure if OC will be safe. I guess it depends on the spectral sensitivity of the specific film, but information on this stuff is scarce. I want to use ATO 2.1 for masking.
     
  2. Rick A

    Rick A Subscriber

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    I am as stumped as you about it being "panchromatic sensitized", as it is supposed to be orthochromatic.

    You cannot use an OC safelight filter with ortho film, needs a dark red filter in my experience.
     
  3. OP
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    michael_r

    michael_r Subscriber

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    I've been doing some googling and it seems depending on the where you pull up the technical sheet sometimes it says panchromatic sensitized and sometimes it says orthochromatic sensitized. I'm starting to think when it says panchromatic it's just an error.

    Anyhow I'm still puzzled as to how it is different from ATO. It seems like ATO is probably higher contrast, but I'm not sure.

    In any case I guess I need to cave in and get a dark red filter for my safelight.
     
  4. Rick A

    Rick A Subscriber

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    I finally gave in and added an OC safelight to my DR. I've only had red for over 40 some odd years. I still use the red most of the time as I mainly use Emaks and Varykon papers, and still have a supply of Forte in smaller sizes.
     
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    michael_r

    michael_r Subscriber

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    The problem I will have is finding a 1A red for my old Kodak safelight. It takes the small 3 1/4" x 4 1/4" rectangles. I don't think Kodak even makes the 1A anymore. Maybe I could try to find a 1, but I don't understand how you can see anything with a 1 (not that I'll be able to find that one either).
     
  6. Gerald C Koch

    Gerald C Koch Subscriber

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    Is a spectral sensitivity curve published for this film? That would answer the question as to whether it is ortho or pan.

    You have to use a red safelight.
     
  7. ath

    ath Member

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    The datashhet of the Rollei Ortho states it is sensitized up to 610nm.
    If it is similar to the Maco Ortho I used years ago you would need a very dim safelight, even with red.

    For a red safelight I recommend a small (!) red LED lamp. Cheap, lasts forever and very bright. Since the colour is generated by the semiconductors (red only) and not filtered from white fading is no problem.
     
  8. nworth

    nworth Subscriber

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    If the film is sensitized to 610 nm, it is panchromatic. It is probably what we used to call Type A panchromatic, with poor red sensitivity (Type B was more or less normal, but still less red sensitive than many current films, and Type C had enhanced red sensitivity), but you need a wedge spectrogram for the film to be sure. Even with reduced red sensitivity, a safelight is an iffy thing. Most red LEDs emit significant light below 610 nm. Check the specifications for one that works around 660 or longer wavelengths. Then follow the rules for pan film - use it for a few seconds only after development is at least half complete.
     
  9. Helinophoto

    Helinophoto Subscriber

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    Just to bump an old thread;
    I did some tests yesterday with this film, trying out no filter, then red, green and yellow filters on my Rolleiflex 2.8F.
    Developed in Rodinal 1:25 for 4 mintues.

    Results were that the unfiltered and the green and yellow were similar, with perhaps a little more contrast with the yellow filter.

    With the red filter, i got a blank frame (Rollei Hellrot), so this film doesn't see red at all. I had a similar experience a few years back, photographing a model wearing a santa-costume; Her lips were black, and so was the santa-cap ^^
     
  10. Rick A

    Rick A Subscriber

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    The subject of filters in this thread, is safelight filtration. True orthochromatic film can be handled under dark red light without problem, instead of total dark condition, much like paper in the dark room. True ortho film has no red sensitivity. I use a couple of different types of ortho film, one being medical Xray film, the other is Arista ortho sheet film. Being able to switch on a dim light to see what I'm doing makes life easy.
     
  11. Helinophoto

    Helinophoto Subscriber

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    Yes, I know.
    Point was that the Rollei was not exposed using a regular red-filter in-camera, wouldn't that be more or less the same as using a red safelight?
     
  12. greg zinselmeier

    greg zinselmeier Member

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    correct. whether it be in camera or in Dark room, no sensitivity IS no sensitivity to red
     
  13. Helinophoto

    Helinophoto Subscriber

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    Roger that.

    I was simply adding some information, since they were in doubt about the sensitivity-area of this particular film. (if it was panchromatic or not) :smile:
     
  14. devecchi

    devecchi Member

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    Last week I asked about Rollei Ato 2.1 and Rollei ortho 25:

    Rollei Ato 2.1 is high contrast orthocromatic

    Rollei ortho 25 not really orthocromatic, you must use a red filter very dark for a short time. Is it possible to decrease the contrast with soft development.
     
  15. Bob Carnie

    Bob Carnie Subscriber

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    Here is a silly question... Is Rollei Ortho 25 just Ilford Ortho 25 rebranded?? I have bought both in large rolls and on my laser image setter they respond the same>?
     
  16. pentaxuser

    pentaxuser Subscriber

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    I am completely unfamiliar with ortho film but I think you are saying that without a filter the ortho film rendered the red santa's cap as almost clear on the negative so black on the print?In your test what was the scene you were testing when you used the red filter that gave you a blank frame? Was the frame filled with red material only or are you saying that taking a normal scene with a red filter results in a blank negative?

    Thanks

    pentaxuser
     
  17. Helinophoto

    Helinophoto Subscriber

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    Without filter -> red things turn black (clear on neg)
    With red filter (simple shot of the city out of the window) -> everything black (completely clear frame)
     
  18. pentaxuser

    pentaxuser Subscriber

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    Thanks. So you can completely ruin a roll of ortho film if you use a red filter. I certainly had not realised that. I had thought that a red filter simply made no difference. It sounds as if there ought to be a warning on each box holding ortho film or in the instructions "DO NOT UNDER ANY CIRCUMSTANCES USE A RED FILTER. IT WILL RESULT IN BLANK NEGATIVES

    pentaxuser
     
  19. Rick A

    Rick A Subscriber

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    I wasn't aware that Ilford made an ISO 25 ortho film. Isn't Ilford Ortho+ ISO 80 daylight and ISO 40 in tungsten? I remember Adox and Efke being one and the same not many years ago, maybe Rollei and Adox are the same now?
     
  20. Gerald C Koch

    Gerald C Koch Subscriber

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    If you are using an orthochromatic (not sensitive to red light) film and you use a red filter you will get no image. Plain and simple, end of story.

    Has there been a sale on used threads in the past few weeks? There seems to be a larger than normal number of old threads coming up.
     
  21. Helinophoto

    Helinophoto Subscriber

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    It depends on Google, this was hit nr 1 when I searched for info on this film :smile:))
     
  22. Leigh B

    Leigh B Member

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    No.

    Sensitivity is a quantitative measure.

    There's a huge difference in the quantity of energy in the red portion of the spectrum impinging on the film during 1/60th of a second versus during 10 or more minutes.

    - Leigh