Re: [Frameworks] Extremely Long Exposures - for Months and Years

From: Jason Halprin (email suppressed)
Date: Tue Nov 02 2010 - 14:14:44 PDT

Aditya, As I mentioned before, "metering" is not possible for this kind of variable. When you take a measurement of light, it is an instantaneous measurement. In order to figure this out you would have to take a series of measurements over the course of a year with meticulous data, and then hope that the approximate weather conditions were close the following year. You could do this measurement on one of the solstice days and extrapolate from there (those days being the "average" length of a day for the whole year). Begin a few hours before sunrise and take a measurement every 5 minutes until a few hours after sundown, then average it out... However, why not just start the exposure experiment? You've already done 14 days, why not double it, or triple it? You already have some good date with which to make an educated guess. Or contact an Astronomer in your area. They may be able to direct you to a dataset about the amount of sunlight falling on an average day in your area... -Jason Halprin ________________________________ From: Aditya Mandayam <email suppressed> To: Experimental Film Discussion List <email suppressed> Sent: Tue, November 2, 2010 11:51:13 AM Subject: Re: [Frameworks] Extremely Long Exposures - for Months and Years 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: 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: > > I asked this question on<> as well: > > > 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. > _______________________________________________ > FrameWorks mailing list > email suppressed > > > > ________________________________ > _______________________________________________ > FrameWorks mailing list > email suppressed > > > _______________________________________________ > FrameWorks mailing list > email suppressed > > > _______________________________________________ FrameWorks mailing list email suppressed

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