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  1. #11
    David A. Goldfarb's Avatar
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    Check out lfphoto.info or any book on view camera technique or macro photography for different approaches to computing bellows factor or magnification factor. There's a thread here on bellows factor, where I think I posted my magnification/exposure table as an MSWord DOC file.

    With small and medium format cameras, it tends to be a concern only in the macro range, and with 35mm it gets taken care of typically with TTL metering, since an in-camera meter is looking through the lens, and the effect of magnification factor on the film is the same as it is on the meter.

    When you're shooting large format, many subjects that you might not have thought of as "macro" with 35mm are suddenly in the macro range. A tight portrait on 8x10" can be at a magnification ratio of 1:3 (size of the film:field of view at the subject position), and the same on 4x5" would be 1:6, requiring additional exposure. With that puny 35mm camera, the same portrait would be 1:24, requiring no exposure compensation at all. If you were photographing something small like a spider with the puny format camera, though, you might be at 1:2, and if you were lighting it with flash and didn't have TTL flash metering, you would have to compute exposure factor there too!

    With landscapes, though, the subject tends to be far away, so bellows factor isn't relevant, which is why your other exposures were okay.
    flickr--http://www.flickr.com/photos/davidagoldfarb/
    Photography (not as up to date as the flickr site)--http://www.davidagoldfarb.com/photo
    Academic (Slavic and Comparative Literature)--http://www.davidagoldfarb.com

  2. #12

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    Good old "inverse square law", She's always good for fits of anxiety. The first lesson in photography should be this principle because it applies to lighting a subject as well as bellows draw. You would probably do well to learn this way of accommodating lights variables, it will only help when you approach and execute images to have this principle stored in your mental tool box.

  3. #13
    David Ruby's Avatar
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    Yowzaa. I better get myself a large format book! Thanks for the help help though. I have a feeling this info will come in very handy, as I definetely have an interest in using my 4 x 5 at close ranges for portraits or what have you. I took some similar images with my 35mm that day also, so it will be interesting to see the differences.

  4. #14

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    as many noted here.. there are intensifiers, i have the fotospeed and works good in those rare cases when it happens(not corrct exposure on 35mm). the selenium is a great thing generally. i always use it. but it will not add details (nothing will add it actually). generally all those methods should be taken as fine tuners and not as saviers of what had not been done.
    the paper is also very importent. agfa mcc is not the best choice in those cases of thin negative. ilford, kentmere oriental is much better.
    what i usually do in those cases is printing on the hardest grade and then maeking the timing of exposure developer and finally putting the developped paper in the deluted selenium for long time (15 +min) it works good with bromide papers since they will not change the heugh.
    but the best way is lith print if u are femiliar with it. thiner negatives are great with the lith but again u have to experimant it to find te best exposure/developing combination.

    again if u follow all those intesification methods from the film to the paper itself while reducing the enlarging magnification u can save your negative and even find some of those stategies to give a very aesthetic photos.
    victor

  5. #15
    gainer's Avatar
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    A previous poster suggested bleaching and redeveloping in a staining developer. This process has worked well for me. I use the same kind of bleach that you would use for sepia toning a print and redevelop in PMK in room light to completion. The silver image is restored and a stained image is added. The process may be repeated. It is not well known that hydroquinone is a staining developer when used without sulfite. It is soluble in isopropanol. Mix Pyrocat-HD using hydroquinone instead of catechol, leaving out the bisulfite, and use it instead of PMK if you wish.
    Gadget Gainer

  6. #16
    gainer's Avatar
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    Let me embellish a little on bleach and redevelopment. A suitable bleach will be a teaspoonful or so of potassium fericyanide, which you probably have on hand, and a teaspoon or so of table salt in a pint of water. The redeveloper can be as simple as 1/4 teaspoon of hydroquinone and 1 teaspoon of sodium carbonate in a pint of water. I have just tested these recipes, so I know they work. Bleach the negative until the image is translucent. Wash but do not fix. Dissolve the carbonate and add the hydroquinone just before redeveloping. Do not be alarmed by the sudden and intense color. 10 minutes at 70 degrees will be bountifully sufficient. Do this in room light. The negative must be exposed. The stain image will add considerable contrast to prints on graded paper and on VC paper with contrast-increasing filtering. There will be no increase in grain or loss of acuity.
    Gadget Gainer

  7. #17

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    Gadget, I too have an underexposed 120 neg that can't be taken again. It was developed in Pyrocat-HD, so it already has some stain. It is of normal or slightly more contrast. (there was nothing wrong with the developer, the film was definitely underexposed)

    Have you any suggestions? I was thinking of acquiring the ingredients for VMI mercury intensifier. I know how to dispose of the used solution, by the way.

  8. #18
    Black Dog's Avatar
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    Is it possible to intensify XP2 negs? With a copper or sepia toner perhaps?
    "He took to writing poetry and visiting the elves: and though many shook their heads and touched their foreheads and said 'Poor old Baggins!' and though few believed any of his tales, he remained very happy till the end of his days, and those were extraordinarily long "- JRR Tolkien, ' The Hobbit '.

  9. #19
    glbeas's Avatar
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    No, they are chromogenic, theres no silver left for the toner to work on. You'd have to find some other exotic chemical that will glom onto the dyeclouds to do any good there.
    Gary Beasley

  10. #20
    gainer's Avatar
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    To John S.

    You can intensify the stain part of the image by the bleach-redevelopment process. When you bleach the negative (probably not a good term to use) in a rehalogenating bleach such as is used in sepia toning, the stain image from development in Pyrocat or PMK remains. Redeveloping restores the original silver and adds to it more stain. Be sure that the negative is well fixed and washed before you bleach it the first time. Any remnant of fixer will combine with the ferri to remove silver permanently.

    Each redevelopment cycle hardens the emulsion a little more.
    Gadget Gainer

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