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  1. #11
    2F/2F's Avatar
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    I have a Mamiya Universal Polaroid setup (3x4, not 4x5) that I might think about trading, but I am ignorant as to Pentax's digital offerings. Does the K20D take old manual K mount lenses? I sometimes want a digital with more resolution than my Canon 10D.
    2F/2F

    "Truth and love are my law and worship. Form and conscience are my manifestation and guide. Nature and peace are my shelter and companions. Order is my attitude. Beauty and perfection are my attack."

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  2. #12
    DWThomas's Avatar
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    Quote Originally Posted by davidst View Post
    Dave's on the right track. And his pics are good.

    ....

    Now trying to find some black metal to punch pinholes into. Ordinary metals are "silver" coloured, and may be causing flare. Any one got ideas on black materials which will take a fine clean pin punched hole?
    (Thanks for the picture compliment and welcome to APUG.)

    I have read claims that some toners will blacken brass. I didn't get very far trying to do that with Kodak selenium and brown toners, but maybe there are concentration issues. I had an ancient sample here of a liquid for blackening aluminum that worked fairly well on the brass shim stock I used on my SQ-Hole camera. I've wondered if gun bluing liquid might work, I think it just needs to be some smelly sulfur compound with the right acidity.

    I don't actually punch the pinhole, I raise a pimple, then sand with fine wet-or-dry sandpaper. Doing that, the initial color of the stock doesn't help.

    DaveT

  3. #13
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    Quote Originally Posted by davidst View Post
    But I like the idea of blackening, as long as there is no gunk build-up in the hole, which then needs cleaning back to shiny metal. Or is the steel black all the way through?

    Any blueing (or blackening), either chemical or heat treatment, is limited to the outer few microns. So yes, the inside would still be silver. If you use the "heat it up and quench in oil" method, you'd want to use a thin oil - Whale oil used to be preferred, but nowadays, perhaps a 3-in-1 would be easier to obtain. Be warned, the vapours will be highly flamable, so do it outside.

  4. #14
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    Quote Originally Posted by paul_c5x4 View Post
    If you use steel, heating up to a dull red and then quenching will turn it black. Many years ago, used to use old engine oil to quench wrought iron work in - With current health & safety rules, you'd be better off using clean oil.
    Case hardening?
    www.EASmithV.com

    "The camera is an instrument that teaches people how to see without a camera."— Dorothea Lange
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  5. #15
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    What an active forum! Great hearing so many diverse views, and beaut ideas right across the spectrum. I just love people who THINK, so many of the flock don't. Thanks for your support since I joined only a couple of days ago.

    The blackening by chemicals has given me an idea. I've still got some sheet sterling silver left over from a bit of silversmithing I had fun with in the past...another "hobby" I must find time for again. So I can punch a fine hole, then heavily tarnish eg blacken the silver using what the trade calls "Liver of Salts" makes rotten egg gas H2S. Stinks but will turn the hole and the whole piece nice and black. Of course still hope the hole doesn't develop any gunk, as reaming to clean for perfect hole, will "resilver" the hole and cause flare.

    I'll keep codging...There must be something rigid, that's black, which will take a pin punch, that's not metal...

  6. #16
    davidst's Avatar
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    [quote=DWThomas;811326
    I don't actually punch the pinhole, I raise a pimple, then sand with fine wet-or-dry sandpaper.
    DaveT[/quote]

    Raising a pimple and sanding, is a great way to get a variable size hole, by the degree of sanding. It also would stretch the metal, making it thinner than the undeformed stock. The pinhole must be in very, very thin material. Otherwise the light train is like going down a tunnel. It must be thin so the light defracts immediately around the edges.

    We are nearly there...

    I have just measured my old hole... pinhole that is. It is 0.4mm (1/64" for you non metric types), and at 120mm from the film plane it is f200, and covered a 4x5 piece of 100iso film. I'd reckon 1/64th should be a relatively easy drill size to get, so can consider drilling through v. thin super black plastic sheet, when I find it.

    The Holga landscape pinhole cameras have black plastic pinholes.

    It's all about the hole Johnny9fingers, so I hope I haven't highjacked your post. Get your camera suitable for the film, but think about the hole. If youve got an old folder, just take the lens out and put a pinhole there, nice easy film transport already incorporated.

  7. #17
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    Quote Originally Posted by 2F/2F View Post
    I have a Mamiya Universal Polaroid setup (3x4, not 4x5) that I might think about trading, but I am ignorant as to Pentax's digital offerings. Does the K20D take old manual K mount lenses? I sometimes want a digital with more resolution than my Canon 10D.
    Thanks for the offer 2F/2F, but I just picked up a Mamiya Universal Press with the 127mm lens and a few boxes of the old Polaroid 655 (665?) pos/neg film. Now I have me eye set on a Konica Instant Press. And yes, the K20D will take the K mount lenses.

    John
    Never met a camera I didn't like...
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  8. #18
    johnny9fingers's Avatar
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    No worries DaveT, sometimes we find little nuggets of info we wouldn't normally get if the thread held firm to the topic. It's all good. Now that I have the Mamiya Universal I'm looking into the best ways to rig it for pinhole work. It seems it can be as simple as a hole in tin foil, to a precisely machined brass pinhole with mounted shutter. This is just too much fun........John
    Never met a camera I didn't like...
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  9. #19
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    Quote Originally Posted by geoferrell View Post
    I've got a Mamiya Universal with Polariod back and just tried the FP-100C instant color film, which makes great pictures, but I am unable to make an image transfer. It was my first attempt and I'm wondering if anyone has any experience with the Fuji materials for image transfers. I think this material is also available in 4x5, and a black and white FP-3000B polaroid type is rated at EI 3200. And the Mamiya is great, but for 4x5 the Speed or Crown Graphic cameras are great and can be inexpensive.
    not sure about image transfer, but there is a dude in Spain that with the FP-100C part that you put in the trash? makes the negative of that actual picture to show up, ready to go into the enlarger. The method is simple, you use a brush and regular bleach and brush the dark side and the negative appears like magic. The bleach can only go into one side of the negative, I guess the non emulsion side, if it goes on the other side it destroys the image. After that you washed to get rid of the bleach. It only works with the Fuji.
    "Art is a lie that enables us to tell the truth" -Picasso
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  10. #20
    johnny9fingers's Avatar
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    Quote Originally Posted by jaimeb82 View Post
    not sure about image transfer, but there is a dude in Spain that with the FP-100C part that you put in the trash? makes the negative of that actual picture to show up, ready to go into the enlarger. The method is simple, you use a brush and regular bleach and brush the dark side and the negative appears like magic. The bleach can only go into one side of the negative, I guess the non emulsion side, if it goes on the other side it destroys the image. After that you washed to get rid of the bleach. It only works with the Fuji.
    Do you have to do the bleach processing right away, or can you store a batch of them and do it later?
    Never met a camera I didn't like...
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