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  1. #1
    fatso's Avatar
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    Tech pan films - please school me !

    Hi all,

    In my quest for making 40" prints from drum scanned rollfilm, I want to try some of the ultra high resolution technical films. How do the latest films compare to Kodak Tech Pan/Technidol ?

    What are the differences between Agfa Copex Rapid, Adox CMS 20, Rollei ATP1.1 ? Is one particularly suited to pictorial photography ? And which developers work best with each film (for pictorial use). Are there any other tech films I left out ?

    Paul

  2. #2
    darkosaric's Avatar
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    Adox CMS 20, available in 120 format as well, with adotech developer. Nothing has higher resolution.

    I have tested Technical pan in technidol with CMS in adotech in small format: I like results from TP more (don't know why, just more pleasing final result), but adox CMS 20 has smaller grain. Making print 30x40cm and using grain focuser - you can't see the grain! It is ridiculous how high resolution and small grain it has. And this is for 35mm, you can imagine how it is for 120 format.

  3. #3

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    Yes, CMS 20 is amazingly fine grained.
    I have used it and Copex-rapid in medium format as well since it came out last year in 120. Only wet printing it thou, enlarged or 6x9 contact copies.
    Copex-Rapid is ISO 50, so its much faster than CMS 20 and more panchromatic kinda film.
    Sometimes I scan the 135 CMS 20... but no drum scanner can come even close to resolve its full detail. Even top of the line drum scanners falls apart around reaching Kodak T-max 400 resolution, CMS 20 is out of the question
    T-max 100 might suit You better for scanning.

  4. #4

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    Kodak Tech Pan differed from such films as Kodak ImagelLink, Agfa Copex. and other microfilms. If you look at Kodak's site for this film you must note that one of its intended purposes was for continuous tone picturial photography. This is not true of microfilms which are designed to provide high contrast images to clearly represent text. This makes it difficult to tame the contrast of these films for pictorial work.

    It is somewhat paradoxical that grainless prints actually appear less sharp to the human eye than prints that contain some grain. This optical illusion is the idea behind such acutance developers as the Beutler formula and Neofin Blue which make use of edge effects.
    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

  5. #5

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    Most 40 inch prints are viewed at sufficient distance that the tiny details are somewhat obscured, but I get the impression that you want these prints to stand close inspection. At 20X enlargement, the imperfections of film and lens resolution as well as diffraction begin to become apparent. If possible, going to a larger negative (4X5 or even 8X10) would give a substantial increase in quality even when using a more or less ordinary film like TMX. For example, if you are shooting at f/8, diffraction limits you to about 200 l/mm; a document film like CMS 20 will give you about 250 l/mm; and a good lens for a medium format camera will probably be about 120 l/mm (maybe a bit more). Combined, this yields a resolution of about 95 l/mm, which gives a print resolution of 120 l/in - a quite noticeable degradation at an arms length viewing distance. A decent 4X5 negative and lens with TMX will yield about 80 l/mm on the negative which equates to 203 l/in on the print - still a noticeable degradation, but a lot better. The results for an 8X10 would show no degradation.

    Your current plan using MF and CMS 20 film will still probably work well. From the example you showed earlier, I don't think the defects in the enlarged image would be very obvious. Grain would be obvious, so your choice of film is important. But if the equipment is available, a larger negative would give better results.

  6. #6

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    Quote Originally Posted by nworth View Post
    .... For example, if you are shooting at f/8, diffraction limits you to about 200 l/mm; a document film like CMS 20 will give you about 250 l/mm; and a good lens for a medium format camera will probably be about 120 l/mm (maybe a bit more). Combined, this yields a resolution of about 95 l/mm, which gives a print resolution of 120 l/in - a quite noticeable degradation at an arms length viewing distance...
    250 lp/mm ( line pairs/mm ) has been reached in format 120 and 135 at ƒ/5,6 white light diffraction limit.
    400 lp/mm ( line pairs/mm ) has been reached in format 135 at ƒ/4 white light diffraction limit, Spur Orthopan UR / Adox CMS 20.

    Resolution lost using decent APO enlarging lens is ~ 5%.
    BW paper is not limiting factor.

  7. #7

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    If you have any textureless areas like an open sky you'll have an awful lot of highly magnified visible
    zits and film blemishes requiring some serious retouch time. Don't expect ideal reproduction of the
    extremes of tonality in the shadows or highlights. These kinds of film come with tonality limitations,
    just as TechPan did. This size print is really territory better suited to large format, but good luck
    pushing the envelope!

  8. #8
    fatso's Avatar
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    Quote Originally Posted by nworth View Post
    Most 40 inch prints are viewed at sufficient distance that the tiny details are somewhat obscured, but I get the impression that you want these prints to stand close inspection. At 20X enlargement, the imperfections of film and lens resolution as well as diffraction begin to become apparent. If possible, going to a larger negative (4X5 or even 8X10) would give a substantial increase in quality even when using a more or less ordinary film like TMX. For example, if you are shooting at f/8, diffraction limits you to about 200 l/mm; a document film like CMS 20 will give you about 250 l/mm; and a good lens for a medium format camera will probably be about 120 l/mm (maybe a bit more). Combined, this yields a resolution of about 95 l/mm, which gives a print resolution of 120 l/in - a quite noticeable degradation at an arms length viewing distance. A decent 4X5 negative and lens with TMX will yield about 80 l/mm on the negative which equates to 203 l/in on the print - still a noticeable degradation, but a lot better. The results for an 8X10 would show no degradation.

    Your current plan using MF and CMS 20 film will still probably work well. From the example you showed earlier, I don't think the defects in the enlarged image would be very obvious. Grain would be obvious, so your choice of film is important. But if the equipment is available, a larger negative would give better results.

    I was afraid someone would mention 4 x 5 I recently saw an exhibit with prints this size made with a Hasselblad and the detail was very decent even up close. I don't mind a little loss of detail and even some grain, I just want to get the best image possible with the equipement I have (Hasselblad V). I've sent some of my negs out for scanning and should have them back tomorrow. They were done with Rollei Pan 25 and developped in Rodinol, shot on a tripod with cable release, I can barely begin to see the grain with a 15X loop, and the detail is fantastic. They're being scanned on a Heidelberg D7100 at roughly 5400 ppi, and the operator is supposed to be quite experienced. I'll be doing a lot of postprod over the weekend and having them printed next week.

    In the meantime I would like to try a high resolution film to compare, but the issue of tonality worries me. How much 'worst' is it compared to 'standard' films like the Rolleipan ? Aren't the Spur and Adotech developpers supposed to make these films suitable for pictorial photography ? And wasn't Tech Pan also considered a document copying film with similar characteristics as CMS (and requiring special developers like Technidol) ?

    Paul

  9. #9

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    "Suitable for pictorial photography" is not an absolute. It is in the eye of the beholder. Depending on the luminance scale of the scene and the desired tonality, suitable? - perhaps. Acceptable? Perhaps. Optimal? Unlikely.

    Tech Pan was a little easier to tame than some of the current utra-high resolution films that can apparently outresolve Tech Pan with finer grain (CMS 20 for example). The tradeoff is a relatively short tonal scale (and very low speed). No matter how much you are able to reduce contrast, the exposure scale will be quite limited in comparison to general purpose films. No matter how fine the grain is, or how high the possible resolution is (and that includes Tech Pan), prints will not look like they were made from large format negatives.

    Technidol was a POTA variant and worked ok. There are several other developer/development options and with any of these films testing will be required because you can get pretty different curves and speeds with the variety of developers.

    In my opinion you answered your own question when you said you don't mind a little grain. If you are looking for the "best image possible", I would say overall print tonality and quality will be far more satisfying with a regular film. All photographic materials involve compromises. For general photography, a regular film will have more grain than a "document" film, but virtually every other characteristic will blow the document film away (and of course you can use bigger film to reduce grain, increase detail, sharpness). Which tradeoff appeals more to you?

  10. #10

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    hi paul

    i hate to suggest this
    but have you thought about modern
    tab grain film and developers that are designed for low grain and hi sharpness ?

    while i have used tech pan ( years ago ) i used it for extreme contrast
    and made 16x20 enlargements from a tiny portion of a 35mm negative with no grain
    it was fun, but using a LF camera and a modern tab grain emulsion with the right developer
    can yield nearly grainless results, even enlarged to the extreme you wish for.

    it only photographers that stick their nose up to a print and say " i can see grain "
    its kind of a disease, and i really don't understand it.

    good luck !
    john
    silver magnets, trickle tanks sold
    artwork often times sold for charity
    PM me for details

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