Does photo paper have an ISO rating?

Discussion in 'Pinhole Photography' started by BetterSense, Jan 11, 2009.

  1. Kimberly Anderson

    Kimberly Anderson Member

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    I'm not sure. I think I'm kind of confused now. I wasn't trying to suggest anything, just trying to figure out what you have been doing.

    Here's my shot from today.

    Several things might be happening:

    1. I might have the ISO incorrectly set for the paper.
    2. I might be processing incorrectly.
    3. I might be scanning incorrectly.
    4. I might be printing incorrectly.

    Those things might all be happening, one at a time, in multiple combinations, or all at once. I am willing to concede that. But...one thing I do know is that I like my negatives and I like the prints I'm able to get from them.
     

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  2. Photo Engineer

    Photo Engineer Subscriber

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    I would like to see the negative scan.

    Your positive scan is considerably lower in contrast than mine, and quite a bit lighter. IDK what that means offhand at this point, but the 3rd patch from the left in the second row of your print is the red patch and should be as black as Dmax taken with this ortho paper, and the right hand bottom patch in the above should be black as well.

    The left bottom patch should equal Dmin.

    Somehow, the positive appears muted to me.

    I looked at my originals here and they look close to the scan of the negative. A print is close to my positive scan as well.

    I would like to add that my process conditions yield good prints with the proper tonality when used with an enlarger exposure of f11 - f16 at 12" for an 8x10 print. I use a 30M filter as per the enlarger instructions for grade 2 and this gives me a gamma of about 2.5 on a Stouffer wedge.

    I would like to add that the negative step scale should show a distinct step in every position in that bottom row, from Dmin to Dmax if you have exposed it properly and developed it properly.

    I would also add that there is nothing wrong with messing with the exposure and process in order to make a good picture, but this is not the way to start measuring the capability of the paper. You start by getting Dmin and Dmax centered with a process that can give good prints by normal means.

    PE
     
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  3. Kimberly Anderson

    Kimberly Anderson Member

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    I scanned the negative then inverted it in Photoshop. I also gave it a bit of a tweak in levels and a minor curve. I was surprized honestly to find that yours and mine were as close as they were.

    I am at home now, so I can't really re-do the scan, but I will and then send the original untweaked version.

    I think that there could be a whole lot to be learned about using paper negatives. I was considering using them for alt-processes later on...

    I'll see what I can't get done tomorrow. I have a bunch of shooting to do, ironically on paper negative, but I'll try to make time to get you a good unmolested scan.
     
  4. jnanian

    jnanian Advertiser Advertiser

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    even though we seem to be all shooting paper at different iso's
    we are getting negatives we are able to print.
    i like printing paper negatives that are a little thin,
    so the positive looks good ..
    maybe that is the difference.
    i over expose and develop like i do, so i can get negatives i will print / contact print, not just scan ..

    Ron

    are you contact printing your paper negatives?

    john
     
  5. Photo Engineer

    Photo Engineer Subscriber

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    John;

    I scan all of them and post them here either as negatives or inverted as positives, or both as I did in the earlier posts. I suspect that some of these very excellent paper negatives were shot on the shoulder (slower) portion of the curve and then underdeveloped to lower contrast to get good contrast from high contrast papers. The alternative would be to shoot on the toe and overdevelop to get good negatives.

    I have done both. In the case in point, I have avoided either, but I could shoot on the toe and probably force things to an ISO 50 or maybe even 100. IDK. I was not trying to do that.

    You can push and pull papers the same way as film and without knowing the ISO, you can do this just to get the picture you want.

    BTW, I "know" that the ISO speed of the Endura Yellow layer emulsion is nearly 100 and that the Cyan layer is about 25. When you add in the filter pack and orange mask, the overall speed to a neutral reduces speed to about ISO 25. I did that experiment at EK as well. You might want to see Bujor B's work on Photo Net where he exposed CA and Endura papers in camera with a Tungsten filter pack and got some good positive color prints by cross processing.

    PE
     
  6. Kimberly Anderson

    Kimberly Anderson Member

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    FWIW...that is the first paper negative I've ever scanned. Most of the time I'm printing them on the same paper I shot them on.

    Here is a post on my blog that shows a bunch of work my junior students did last term. You'll be able to tell the 4x5 and 8x10 paper negs from the 6x6cm film shots one student did.

    Student's Paper Negatives

    The question is, as PE suggests...does anyone want to develop a Zone System for paper negatives? :D
     
  7. Photo Engineer

    Photo Engineer Subscriber

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    Michael;

    You are to be congratulated on the excellent work you are doing teaching these students. Nothing I have said (as a purist) should detract from what is beautiful work. Thanks.

    And yes, there could be two "zones" usable for paper just as there is really only one for film. Well, film has 3 but two are nearly impossible to use.

    Best wishes.

    Ron
     
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    BetterSense

    BetterSense Member

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    A large amount of this discussion is unintelligible to me, but I'm glad people are sorting all this.

    With all that knowledge, any guesses as to a reasonable sunny exposure time for Illford multigrade IV in a 8x10 camera with 6 inch focal length and .5mm pinhole (f/300ish)?

    What I really want is just an ISO number. Since I know my aperture (or can find it), if I knew the speed of my paper I could just meter a scene with another camera and add stops for film slowness and aperture smallness, with maybe a fudge for reciprocity. Possibly it's not that simple, but if it's so complicated I can see just going for $3 a pop for sheet film, then at least I can get an ISO rating and reciprocity data that I can understand.
     
  9. keithwms

    keithwms Member

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    Ah, I'd say give it about a minute.

    Of course, you can shoot test strips on one sheet by withdrawing the darkslide in increments. Then develop the whole sheet, dry it, contact print it, and once you see your final print, you'll know straight away how you want to rate and expose the paper next time.
     
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  10. Kimberly Anderson

    Kimberly Anderson Member

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    Speaking of paper negatives...is anyone using the 'positive' paper that is sold at Freestyle? I ordered a box way back in September and it's still not here yet. :sad: Was hoping to create some 'photographic monotypes' with the larger cameras.
     
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    BetterSense

    BetterSense Member

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    What's a darkslide?
     
  12. keithwms

    keithwms Member

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    I never got anything but unmanageable contrast with that stuff, I am sorry to say. Somebody here did report acceptable results but I'm afraid that I don't recall who it was.
     
  13. keithwms

    keithwms Member

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    Are you loading the paper in a film holder? If so then the thing you pull out is the darkslide.
     
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  15. Greg Heath

    Greg Heath Subscriber

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    Quick question. congrats on your 8x10 foam camera. I have never used a 4x5 film holder, so picked up an older Fidelity holder and want to make a foam 4x5 pinhole camera.

    Can I use the film Holder for only 4x5 film or can I load RC paper into it ?
     
  16. Joe VanCleave

    Joe VanCleave Member

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    Congrats, Michael, to both yourself and your students; those images are wonderful.

    Regarding Efke's Direct Positive paper, I worked with it last summer. I was able to get some good images, some of which I posted here several months ago (they're on another computer else I'd repost them again now); suffice it to say that I had to preflash the bejeezus out of the paper to get a reasonably normal image in bright daylight with some semblance of midtones.

    IIRC, whereas my "normal" preflashing time for grade 2 paper negatives is 10 seconds using my lighting setup, with the Efke paper I used a preflash time around 30 seconds. And near this 30 second time small adjustments in preflash time had large effects on the overall exposure and contrast of the image.

    Also, I rated the Efke paper at a personal exposure index of 1, rather than the 3 I apply to my grade 2 paper negatives.

    Earlier, PE said: "You brought up an important point. You have overexposed to fight contrast. Well, if you overexpose and either under develop to get lower contrast or develop normally, you will be talking about at least 2 stops which is about ISO 6 or thereabouts. This will reduce the contrast nicely, but it will not center a tonal scale at normal development.

    All of my photos include the MacBeth Checker and have the neutral scale centered with Dmin on one side and Dmax on the other, and they were given normal development, no under or over, and no flash.

    I think that all of this is important. I am trying to get at the full tonal range. To actually do this with a paper, I suggest a grade 0 or grade 1 graded paper."


    Perhaps all I'm doing is over-exposing and under-developing the paper to get a good tonal range from daylit scenes. That makes the meaning of film speed less useful, of course.

    And I use graded paper rather than multigrade; I think the use of multigrade while trying to determine a useful personal exposure index just confuses the issue.

    My experience with using paper as an in-camera negative is that I don't treat the exposure and development the same as when using paper as a print media. For instance, I do not desire a negative where the scene's highlights appear almost paper black on the negative; this would be the equivalent of blowing out the highlights on film. Neither do I desire to develop the paper fully to "completion"; that would be the equivalent of over developing the bejeezus out of film. A good paper negative has highlight details that are dark gray at most, nowhere near approaching maximum paper black; and shadow detail just below paper white, like feathery traces of tone. The overall appearance of such a negative is a very low contrast, nothing like the dramatic contrast one can achieve with the print.

    The approach to using paper as a sort of film is very film-like. And the approach to using paper as a print media is, well, much different from film. So I suppose the debate over what's the optimal exposure index for paper is really about finding a way to systematize the exposure of paper negatives using light meters whose spectral sensitivity doesn't match the paper at all. It's cobbling together a method of working with a material in ways it was not designed to work, using tools that aren't intended for that application.

    I still don't understand the divergence of experience we seem to have regarding reciprocity of paper, however:

    "No, I suspect reciprocity perhaps in these experiments. IDK. Paper is generally not intended for being used at much below 1/2" or much about about 90" or thereabouts. I would think that we are all outside of this range in one way or another. IDK."

    I've found consistent results while using grade 2 Arista paper in pinhole cameras where the exposure times range from 30 seconds to 5 minutes; and equally consistent exposures in glass lens cameras using shutter speed of fractions of seconds. In all cases my personal exposure index of 3 seems to work well.

    I find paper to be a wonderful medium to work with, especially in large format, glass lens cameras. The resulting contact prints are easy and fun to work with.

    ~Joe
     
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  17. jnanian

    jnanian Advertiser Advertiser

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    yup :smile:
    you can put rc paper, fiber paper, hand coated paper ...
    have fun! ...

    john
     
  18. Greg Heath

    Greg Heath Subscriber

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    great

    Thanks for the answer..

    I can't wait to get started.
     
  19. fschifano

    fschifano Member

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    Yes, you can. RC paper works best. Thinner is better if you plan to contact print the paper negatives.
     
  20. jnanian

    jnanian Advertiser Advertiser

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    wow, 5 pages of discussion on paper negatives :smile:
    maybe we should start a paper negative group ?

    john
     
  21. keithwms

    keithwms Member

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    How 'bout a paper neg exchange?
     
  22. Photo Engineer

    Photo Engineer Subscriber

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    BTW, Ilford MGIV or indeed any paper can be reversal processed to give some very nice reversal prints or paper positives in-camera. In this case, you do lose a lot of speed though. You don't need a special reversal paper.

    PE
     
  23. OP
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    BetterSense

    BetterSense Member

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    Please elaborate.
     
  24. Kimberly Anderson

    Kimberly Anderson Member

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    +1
     
  25. Photo Engineer

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    I assume you mean to refer to my post.

    It is well known that all B&W films can be processed to give reversal images with a special kit made by Kodak and a number of other companies. It is less well known that the same process will work with paper, but with a loss in speed and a need to tweak the developers a tad to get the right contrast.

    There are several threads devoted to this on APUG.

    PE
     
  26. Kimberly Anderson

    Kimberly Anderson Member

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    Ooooohhhhh, very interesting. Too bad you lose speed...I don't know how much more speed I can stand to lose.

    My shooting this morning went very good. I have many excellent examples of negatives. This discussion caused me to re-evaluate my shooting exposures and development combo, and I think I am getting a better handle on the ability to control contrast via exposure/development with the paper negative.

    I have learned a lot in this thread. Thanks to all who have contributed.
     
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