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  1. #1
    Toffle's Avatar
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    Pinhole/Cyanotypes

    Hi folks;

    Just a quick question while I try some experiments here... Has anyone had experience/success in combining pinhole photography with the cyanotype process? I imagine it must work, though the exposures might be astronomically long. Given that a contact print "new" cyanotype prints out in 2-3 minutes in full sun, how would you calculate exposure times for pinholes? (I have calculated that for the dimensions I am using for my experiments that the optimal pinhole for conventional paper is ~.75mm)

    Any tips would be greatly appreciated.

    Thanks,
    Last edited by Toffle; 08-22-2007 at 06:30 PM. Click to view previous post history.
    Tom, on Point Pelee, Canada

    Ansel Adams had the Zone System... I'm working on the points system. First I points it here, and then I points it there...

    http://tom-overton-images.weebly.com


  2. #2

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    g'day Toffle,

    not one reply! no-one willing to put it out there?

    it's generally advised that cyanotype is far too slow for anything but contact printing

    however, why not have a go?

    i've actually been thinking about this for a couple of days after a fellow uni student suggested the same thing, she wants to make extremely long exposures, read weeks

    i do a lot of exposures on FB paper in home made simple lens cameras. with an ISO of 6 and an aperture of f64, and allowing for RTF, exposures are very often 10's of minutes or more

    how to proceed? i guess you'll have to do test shots in multiples of hours to determine ISO.

    Ray

  3. #3
    Toffle's Avatar
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    Thanks Ray;

    I've been doing some crunching. As far as I can tell, if you were making a direct cyanotype print through a .75mm aperture, it would take at minimum 5 hours. How this translates when we start talking about reflected light, I do not know. I'm going to set up my "box" tomorrow morning and check it periodically throughout the day. I could use a larger aperture, but my reading so far indicates that I'm in the right ball park as far as regular pinholes are concerned.

    (By the way, yes, I know that even if this works, I'll be creating a negative image.)

    Thanks again,
    Last edited by Toffle; 08-22-2007 at 10:55 PM. Click to view previous post history.
    Tom, on Point Pelee, Canada

    Ansel Adams had the Zone System... I'm working on the points system. First I points it here, and then I points it there...

    http://tom-overton-images.weebly.com


  4. #4

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    an excellent start Toffle,

    some questions if i may;

    what maths did you use to determine 5hrs?

    why .75mm? what maths?

    given that f stop equals distance from pinhole to light sensitive material (focal length) divided by diameter of pinhole, what dimensions and maths?

    Ray

  5. #5
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    You might want to look into the Cyanotype Rex version of the process. It is suppose to deliver camera-speed cyanotypes. It was invented by Terri King. I don't know the details of it, but think it might involve coating the paper with Ferric ammonium citrate...and use it to make your exposure. Then develop the "negative" in the Potassium ferricyanide. Something like that, anyway.

    But it sounds like a way to bring down your exposure times.

    Vaughn

  6. #6
    Toffle's Avatar
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    Quote Originally Posted by Ray Heath View Post
    an excellent start Toffle,

    some questions if i may;

    what maths did you use to determine 5hrs?

    why .75mm? what maths?

    given that f stop equals distance from pinhole to light sensitive material (focal length) divided by diameter of pinhole, what dimensions and maths?

    Ray
    Hi Ray;
    I downloaded a pinhole design program from www.pinhole.cz. This gave me my basic figures, which I double-checked... um... somewhere else. (I looked at so many sites, I've forgotten which one) Anyway, my results were similar with both calculations, so I figured I was close.

    My figures are as follows:
    My coated sheet is 8X10
    Focal length is 11"
    Which results in an optimal pinhole of .75mm
    These numbers, crunched through the pinhole design program, yield an aperture of f373

    Compared to measurable exposures at f22, we end up with an exposure between 5 and 10 hours. (It's a good thing I'm on vacation )

    All this being said, numbers are really not my thing. I have struggled with dyslexia all my life (the real thing, not the lazy excuse for not doing homework) and can't always get things in the right order.

    I'll try my setup tomorrow and see what happens.

    Cheers, mate.
    Tom, on Point Pelee, Canada

    Ansel Adams had the Zone System... I'm working on the points system. First I points it here, and then I points it there...

    http://tom-overton-images.weebly.com


  7. #7
    Toffle's Avatar
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    Vaughan,
    I haven't heard of that process. It sounds interesting; I'll do some more research. For now, though, I'll stick to Mike Ware's formula. I'm familiar with it. (and I have it.)
    Thanks,
    Tom, on Point Pelee, Canada

    Ansel Adams had the Zone System... I'm working on the points system. First I points it here, and then I points it there...

    http://tom-overton-images.weebly.com


  8. #8

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    Tom,

    If you get it to work, perhaps you would like to find out about the "pellet process" form of cyanotype - it gives a positive image instead the usual negative image.

    Just google "pellet process"

    Regards,
    Neil.

  9. #9
    Toffle's Avatar
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    Quote Originally Posted by Neil Miller View Post
    Tom,

    If you get it to work, perhaps you would like to find out about the "pellet process" form of cyanotype - it gives a positive image instead the usual negative image.

    Just google "pellet process"

    Regards,
    Neil.
    Thanks Neil;

    I'll do that.

    I got my test ready to go before bed last night. (about 3:00 AM... don't ask) We woke to about four hours of rain this morning. By the time I moved my setup outdoors, it was about 10:30 AM. It's mostly clear, so I'll let it sit for most of the day and see what I get.

    Thanks again,
    Tom, on Point Pelee, Canada

    Ansel Adams had the Zone System... I'm working on the points system. First I points it here, and then I points it there...

    http://tom-overton-images.weebly.com


  10. #10

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    sounds great. i love shooting pinholes. one suggestion. why not use a 6 inch box? you would get an f stop of about 330. that may reduce your exposure times. i shoot 8x10 with this set up and it is a good FL.

    keep us posted.

    eddie
    photoshop is somewhere you go to buy photo equipment.


    lens photos here

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