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  1. #21
    NER
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    Andre - I've stated my question and the reasons behind it. If you have something more constructive to say, I'd like to hear it. If not, please go hijack some other thread. Thanks.

  2. #22
    NER
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    Quote Originally Posted by lee
    while 25 sheets of PL 100 is $109.99 at JandCPhoto.

    I think you need to check the JandC Photography website again. Looking at the website, tells me that the Efke is packaged as a 50 sheet box. There by making it about $54.99 per 25. That compares favorably to the BPF 200 from the Bostick and Sullivan company.

    I have no interest in JandC Photography other than wanting to see the company succeed.

    lee\c
    You're right. 50 sheets/box. My mistake.

  3. #23
    NER
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    Quote Originally Posted by gma
    I think it would be very difficult to tell the difference between 80 and 90 lines per mm.in the negative. Paper can resolve only 30 or so lines per mm and unless you are examining your enlargements with a loupe I do not understand your concern.
    I have no idea what you're talking about. According to John Carroll (Photographic Facts and Formulas, Prentice-Hall/Amphoto 1976), the human eye is thought to be capable of resolving 1/100 inch at normal reading distance, i.e., about 0.254 mm. I just want to know the resolving power of BPF 200.
    Last edited by NER; 08-02-2004 at 11:49 PM. Click to view previous post history.

  4. #24
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    Quote Originally Posted by gma
    I think it would be very difficult to tell the difference between 80 and 90 lines per mm.in the negative. Paper can resolve only 30 or so lines per mm and unless you are examining your enlargements with a loupe I do not understand your concern.

    So, if a paper can only resolve 30 lp/mm paper, and your film can only do 90 lp/mm you can only enlarge your negative three times before the image becomes blurred. For a 35 mm negative that would mean a 7,5 x 10,5 cm (3x4 inch) print. Don't you think that's a little bit small? ;-)
    Wilbert
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  5. #25

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    NER,

    I can see that this thread has become a little tense and what I have to say is not intended to annoy you, just to approach it from a different angle...

    What are your reasons from considering moving to PL100 from a film which you like and presumably know well? Finer grain?

    If you are shooting 8x10, the LPMM issue is all but irrelevant in that both are traditional films and will be a million miles away from TMAX 100 or acros and probably quite similar to each other in terms of LPMM/resolving power. Between the films listed the resolution issue is unlikely to become significant below 30 or 40 inch prints if at all.... The 'look' will be much more important and the tonal characteristics and curve may be very different. A good example would be Acros and Tmax100, which on paper are very similar (curves, grain etc) but on a print I think are very different. If you use PL100 (A truly beautiful film) you can always bend it a little by selecting a different dev to the one you are using now. All I am saying is that the Lpmm will tel you little to nothing about its photographic potential for YOU. Use it, develop it, experiment a bit and print it, then decide! I bought quite a lot of TMAx 100 readyload before I realised that I did not like the look of it on paper! I thought all the folk who said they did not like the look of it to have a touch of emperors clothes about them. Not so. I f you like traditional films, you will like PL100. Good luck, Tom

  6. #26
    NER
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    Gilbert, thank you for your question. Tom, I think you are right. In the end, I will base my decision on several factors, including a few that are not so easily quantified (e.g., how does it "look" when printed). As I said above, the resolving power of the film gives me only one indication of what I might expect from this film: it is not the only factor I consider and my decision to stick with PL 100 will, of course, not be based solely on consideration of that characteristic. I am merely trying to approach this in an informed way vs. methods more haphazard. I would do the same if I were contemplating a new developer or printing paper, i.e., try to estimate how the developer or paper might be different from what I currently use before I spend the time and money investigating it. I don't expect there to be much difference between the films insofar as grain is concerned, certainly not at enlargements approaching 20x24, which is about as far as I can go from 8x10 negatives given the design of my darkroom. I appreciate your observations, and I am not annoyed by your remarks. I was, however, a little exasperated by some of the comments yesterday. My inquiry was a straightforward one which I thought deserved a straightforward answer, not replies explaining how resolving power is affected or counterquestions about my motives, for example.

  7. #27

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    I far prefer the haphazard.... continually chasing my tail stops me getting bored as I never win

  8. #28
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    Hi Norman,

    In "Post Exposure" Ctein states that the human eye is limited to a resolution of 10 lp/mm on print. But because our eyes are even more sensitive to acutance, we need 30 lp/mm for a print to look perfectly sharp, even if we cannot distinguish the linepairs anymore.

    All this goes for a 8x10 inch print. Larger formats need less because you look at them from a bigger distance. 20x24 inch prints would maybe need 12 lp/mm. So, with a film resolving 80 lp/mm this means an enlarging factor of about 6 times. For a 20x24 print you would need a negative of 3,3 x 4 inch.

    Considering the fact that your cameralens, the enlarging lens and processing all influence resolution, I guess that with a 80 lp/mm film a 4x5 inch negative is about right for perfectly sharp 20x24 prints. Since you are using 8x10 negatives, BPF 200 has lots of resolution to spare. I guess you will not see any difference between the sharpness of PL 100 and BPF 200 in print.

    Ofcourse, the film character, gradation, foot and shoulder behaviour etc. are all important factors to consider. But film resolution shouldn't be when you are using anything larger than 4x5 inch negatives.

    Just my 2 cents.

    Gilbert
    Wilbert
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  9. #29
    NER
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    Bergger has responded to my question. They report that it's 80 lines/mm. Thank you for your interest in this topic.

  10. #30

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    B.T.W. Look at ARISTA.EDU film from Freestyle in L.A. Supposed to be the same as BPF, J&C etc. 8" x 10", 25 sheets, ISO 200 for $33.99.
    Howard


    Quote Originally Posted by NER
    Bergger has responded to my question. They report that it's 80 lines/mm. Thank you for your interest in this topic.

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