From: Aditya Mandayam (email suppressed)
Date: Tue Nov 02 2010 - 09:51:13 PDT
I have tested exposures of 1 day, 2 days, 1 week and a fortnight using
pinhole cameras and paper.
Here is an example of a week long indoor exposure:
http://farm5.static.flickr.com/4126/5139678697_8552788b30_b.jpg
The pinhole camera had an f-stop of around 250.
This was performed indoors, which allows larger exposure times. Indoor
long exposures allow much longer exposure times.
I reiterate my question : how would you meter for an outdoor exposure
over a year?
On Tue, Nov 2, 2010 at 1:35 PM, Elizabeth McAlpine
<email suppressed> wrote:
> Some years ago – I made a very long exposure still image not nearly as long
> as you are suggesting but it was about 7 hours – I found that shooting on to
> duplicating film helped lengthen the exposure – it has a very low IOS I also
> used a lot of ND filters on the front of the camera which helped to lengthen
> the exposure time – I was shooting in candle light – and the print ended up
> having a very red cast – I was never sure if it was caused by the candle
> light or the duplicating film – but it worked for my purpose
>
> working with pinhole aperture will defiantly increase you exposure times.
>
> best
> Elizabeth McAlpine
>
>
>
> On 02/11/2010 12:03, "Jason Halprin" <email suppressed> wrote:
>
> Well...Long story short, a very long exposure of months or years would be
> very difficult or nearly impossible to meter for. When you meter for a shot
> you are basing the characteristics of the film on the straight-line portion
> of the characteristic curve - meaning that the film has a more-or-less
> linear relationship between exposure and density.
>
> If you were to expose for months, you would be exposing in the "shoulder"
> area of the curve, that area where an increase in exposure results in an
> ever decreasing ratio of exposure to density. Essentially, you are working
> with a situation where most of the possible silver-halide has been
> activated, and the film no longer has linear, predictable results.
>
> Now that that's out of the way, I would propose making your own pin-hole
> aperture (f64 ? smaller?) and centering this on the back of the lens to
> lower the amount of light getting to the lens. Also, use a very slow
> film...and test, test, test. Don't expect a doubling of exposure time to
> result in a stop of increase in density (it won't be nearly that much). It
> would seem the easiest option would be to rig a cable release on an SLR
> camera so that you can leave it open, on a tripod, for a very long
> time...vary your exposure, and take good notes.
>
> -Jason Halprin
>
>
> ________________________________
> From: Aditya Mandayam <email suppressed>
> To: email suppressed
> Sent: Tue, November 2, 2010 6:40:11 AM
> Subject: [Frameworks] Extremely Long Exposures - for Months and Years
>
> Hello, I am interested in making extremely long exposures: of the
> order of many months, perhaps a few years.
>
> E.g: http://photoslaves.com/open-shutter-by-michael-wesely/
>
> I asked this question on photo.net <http://photo.net> as well:
> http://photo.net/black-and-white-photo-film-processing-forum/00XKLr
>
> I would like to know how to meter for such long exposures. What amount
> of light does one assume? Average brightness of a day over a year?
>
> Thank you.
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