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  1. #11
    rwyoung's Avatar
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    Quote Originally Posted by tlr120 View Post
    How do you prevent overexposure? Do you cover it up during daylight? If you were to take an evening shot with the pinhole camera used, not knowing his aperture(maybe f175) maybe an exposure of 10 to 20 minutes. But 6 months and no over exposure?
    The whole point is a to make a gross overexposure because DOP (developing out paper) will act like POP (printing out paper) under those conditions. Any use of chemical developer would blacken the paper and chemical fixer while it will fix the image, it tends to bleach it back a bit too.
    Don't sweat the petty things and don't pet the sweaty things! http://rwyoung.wordpress.com

  2. #12
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    Quote Originally Posted by rwyoung View Post
    The whole point is a to make a gross overexposure because DOP (developing out paper) will act like POP (printing out paper) under those conditions. Any use of chemical developer would blacken the paper and chemical fixer while it will fix the image, it tends to bleach it back a bit too.
    This might be true for B&W, but we've got color in the example provided by the OP. I'm trying to figure how to get the color dyes to form without developer and I'm drawing a blank.

    Of course, it would be possible to use a smaller pinhole. The so called "optimal" pinhole isn't required to get an image.

    The example shown is not a night-time image. The caption identifies it as a solargraph, and if it were the moon, the tragectories would not be parallel, but interwoven, and the brightness of the lines would show darkening and lightening due to the phase. Might be very interesting.

  3. #13

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    So then he would be covering the camera at night time?

  4. #14
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    Quote Originally Posted by tlr120 View Post
    So then he would be covering the camera at night time?
    Wouldn't need to. The trail left by the moon (the moon has about the same brightness as a parking lot on the earth on a sunny day) would be obliterated by the composite daytime terrestrial image. The moon doesn't stay in one place on the film/paper, but every point on the daytime exposure remains in the same place, so there is a visible image of the terrain. The moon's trail would be insignificant. It is very doubtful that you could even see it.

    I often ask my students how bright the moon is, and typically I get "really bright" or sometimes even "as bright as the sun". We think of the moon as bright because our eyes adapt to the low level of light at night. The sun is vastly brighter than the moon.

  5. #15

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    Quote Originally Posted by bowzart View Post
    This might be true for B&W, but we've got color in the example provided by the OP. I'm trying to figure how to get the color dyes to form without developer and I'm drawing a blank.

    Of course, it would be possible to use a smaller pinhole. The so called "optimal" pinhole isn't required to get an image.

    The example shown is not a night-time image. The caption identifies it as a solargraph, and if it were the moon, the tragectories would not be parallel, but interwoven, and the brightness of the lines would show darkening and lightening due to the phase. Might be very interesting.
    http://www.solargraphy.com/index.php...d=13&Itemid=14
    http://www.solargraphy.com

    Remember, the solargraph image located at the link posted by Art is a positive which was created by scanning the overexposed paper negative and then inverting the colors digitally. The colors you see are the result of inverting the original paper negative. Solar prints are very similar. But instead of using an item such as a plant leaf to create a sillouette, in the solargraph you use a pinhole to create the negative image over a very long period. Hours or months.
    Last edited by DannL; 12-18-2008 at 01:15 PM. Click to view previous post history.
    "Lo único de lo que el mundo no se cansará nunca es de exageración." Salvador Dalí

  6. #16
    rwyoung's Avatar
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    Quote Originally Posted by bowzart View Post
    This might be true for B&W, but we've got color in the example provided by the OP. I'm trying to figure how to get the color dyes to form without developer and I'm drawing a blank.

    Of course, it would be possible to use a smaller pinhole. The so called "optimal" pinhole isn't required to get an image.

    The example shown is not a night-time image. The caption identifies it as a solargraph, and if it were the moon, the tragectories would not be parallel, but interwoven, and the brightness of the lines would show darkening and lightening due to the phase. Might be very interesting.
    Yes, you do get some colors. It is quite odd, perhaps somebody like PE or Kirk or Ian could explain the electrochemical reaction that is occurring in the emulsion with these gross over-exposures. And I would think "color dyes" to be the wrong description but honestly that is just a gut feeling and has no other scientific or experimental basis.

    One thing I've found playing around using Illford (MGIV RC), Kodak (PolyContrast III and Kodabrome) and Foma (Fomatone / Arista Edu.Ultra) papers to make contact prints from negatives using long 30 and 40 minute exposures in direct sunlight is I get peachy-browns, browny-purple and sort of a green and tan combination each from a different brand and style of paper.

    The long 6 month exposure I made was using Arista Edu.Ultra (Foma) and had a distinct purple overtone. When scanned and color inverted it did show a rather distinct "mapping" of colors to reality that I just can't explain.

    All in all, a very neat trick!

    And by the way, Tarja (at least I think that is her name), the gal that created the Solarography site, does take a few Photoshop liberties with color adjustment. She did ask permission before doing so and I gave it to her. The end result was a bit more "green" to the grass than the raw scan and invert I submitted. The non-manipulated color inversion is in my gallery space here :
    http://www.apug.org/gallery/showphot...2&ppuser=11966

    And also over at my blog (see SIG tag line below) I have both the "negative" and "positive" versions.
    Last edited by rwyoung; 12-18-2008 at 01:56 PM. Click to view previous post history. Reason: added link to my image in gallery
    Don't sweat the petty things and don't pet the sweaty things! http://rwyoung.wordpress.com

  7. #17

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    [QUOTE=bowzart;723816]Wouldn't need to. The trail left by the moon (the moon has about the same brightness as a parking lot on the earth on a sunny day) would be obliterated by the composite daytime terrestrial image. The moon doesn't stay in one place on the film/paper, but every point on the daytime exposure remains in the same place, so there is a visible image of the terrain. The moon's trail would be insignificant. It is very doubtful that you could even see it.

    Actually makes sense

    Lee

  8. #18
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    Quote Originally Posted by rwyoung View Post
    Yes, you do get some colors. It is quite odd, perhaps somebody like PE or Kirk or Ian could explain the electrochemical reaction that is occurring in the emulsion with these gross over-exposures. And I would think "color dyes" to be the wrong description but honestly that is just a gut feeling and has no other scientific or experimental basis.

    So, we are talking about B&W papers. I was assuming (bad!, bad!) that the original negative must have been done on color paper. Hence my reference to color dyes.

    Most of us I'm sure have found test strips etc. in the bottom of the sink, with strange but sometimes rather beautiful colors. I recall that Scientific American published an article about it in the early - mid 1990's. These colors were used in finished prints by one artist, at least -- Edmund Teske. Really quite amazing. So, I guess that conceptually, I can imagine this working, although I certainly don't know how.

    http://www.getty.edu/art/exhibitions/teske/

    http://artscenecal.com/ArticlesFile/...0/ETeskeA.html

    I remembered that in the 1910 Encyclopedia Britannica there is a section about early experiments in trying to get color to record itself. I am attaching a scan (cut and pasted) of it. Just in case someone might find it interesting..
    Attached Thumbnails Attached Thumbnails colorbritanica.jpg  

  9. #19
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    The whole point is a to make a gross overexposure because DOP (developing out paper) will act like POP (printing out paper) under those conditions.
    I'm a noob to chemical photography and I don't understand what this means. I sort of understand how silver-gelatin photography works and I'm not understanding how an image is formed without developing the paper.

  10. #20
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    Well, I'm an oldbb but I don't quite get it either. I think (and I'm opening myself eagerly to correction) that we are dealing with two principles here.

    In the days of albumen printing which began in about the 1860's and still has adherents (Linda Connor is a prominent name here) papers could be simply printed in sunlight (or under UV today) and they would darken with the exposure to light. They didn't need to be developed chemically. They would need to be fixed to keep them from continuing to darken under continued exposure to light, such as one needs to view them. For a long time, photographers made proofs for portrait clients on "POP" (printing out paper) because they weren't permanent. If the client framed the pic, it would get darker and darker until it disappeared altogether. Current materials will do this to some extent, perhaps some more than others. Typically, the densities achievable this way are pretty wimpy. With REAL POP papers, they were stunning.

    The other principle that comes to mind is Solarization. Seems to me that "solarprint" suggests this. When we speak of "solarization" usually what is meant is not solarization at all, but the Sabbatier effect (look up Man Ray, if that term eludes you). True solarization is an actual reversal. If you expose, as St. Ansel did, and Wynn Bullock also, long enough with the bright disk of the sun in the image, the sun will actually begin to LOSE density in the image. You can look up the images; they are invariably titled "Black Sun". I have done this also. It is not really hard, it is just that you don't get it to happen automatically; luck is still a factor. The way this works is that the characteristic curve of a film is only 1/2 of the whole curve; it is actually something like a "bell curve". Given enough exposure, the response will produce a mirror image of the curve we know so well and love. There were pre-solarized products offered which would automatically produce positive images from exposures with positives.

    So, with a six month exposure, one MIGHT achieve sufficient density, as well as a true and thorough solarization.

    Am I right?

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