Archived posting to the Leica Users Group, 2015/10/01
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]The Effect of Gamma Rays on Man-in-the-Moon Marigolds. On 10/1/15 10:19 PM, "John D. Nebel" <john.nebel at csdco.com> wrote: > In 20 years, cosmic rays may have slightly fogged the ASA 400 film, be > interesting to see. Worth a go anyway. > > "Ambient Background Radiation (Effects on Raw Stock > Ambient gamma radiation is composed of two sources: a low energy > component which arises from the decay of radionuclides and a high energy > component which is the product of the interaction of cosmic rays with > the earth's upper atmosphere. The radionuclides responsible for the > low-energy photons exist in soil and rock and are carried into earth > derived building materials such as concrete. Lead shielding or storage > deep underground may be helpful, but for long-term raw stock storage, > radiation will still be a factor. Upon exposure to ambient-background > radiation, photographic materials can exhibit an increase in minimum > density, a loss in contrast and speed in the toe, and an increase in > granularity. > > The change in film performance is determined by several factors, such as > the film speed and length of time exposed to the radiation before the > film is processed. A film with an Exposure Index (El) of 500 can exhibit > about three times the change in performance as a film with an El of 125. > While this effect on a film product isn't immediate, we still suggest > exposing and processing the film soon after purchase. We recommend a > period of no more than six months from the time of film purchase before > exposure and processing, provided it has been kept under specified > conditions. Films kept for extended periods beyond six months may be > affected, especially the faster films, even if they have been frozen. > The only way to determine the specific effect of ambient-background > radiation is to make actual tests or measurements by placing a detector > in the location where the film is stored. The most obvious clue is the > observance of increased granularity, especially in the light areas of > the scene." > > <http://motion.kodak.com/motion/Support/Technical_Information/Storage/storage_ > info.htm#radiation#ixzz3nNB04BHX> > > > > On 10/1/15 6:07 PM, Richard Man wrote: >> Ken, I will take them.Please send paypal/address info. >> >> Thanks >> >> On Thu, Oct 1, 2015 at 10:13 AM, Kenneth Lassiter <kenlass904 at >> gmail.com> >> wrote: >> >>> As part of my downsizing, I must remove my stash of film from the >>> freezer. >>> Thi sfilm was fresh when it was put into the freezer 20 years ago. It >>> should be perfect when warmed to room temperature. It has been stored in >>> the plastic cans inside freezer bags inside a large plastic container and >>> always in the freezer. >>> >>> Price REDUCED:US$60 for the lot of 115 rolls including shipping in the >>> USA. >>> >>> OR US$0.75/roll plus shipping. >>> >>> *# Rolls* >>> >>> *Film* >>> >>> *135-36 exp* >>> >>> *135-24 exp* >>> >>> 25 >>> >>> Ektachrome 200 Daylight >>> >>> X >>> >>> >>> >>> 26 >>> >>> Ektachrome 100 VS >>> >>> X >>> >>> >>> >>> 15 >>> >>> Fuji 100 Daylight slide film >>> >>> X >>> >>> >>> >>> 7 >>> >>> Fuji 400 Provia >>> >>> X >>> >>> >>> >>> 4 >>> >>> Ilford Delta B/W >>> >>> >>> >>> X >>> >>> 7 >>> >>> Kodak Supra 100 Color Neg >>> >>> X >>> >>> >>> >>> 5 >>> >>> T-max 400 >>> >>> X >>> >>> >>> >>> 8 >>> >>> Fuji Sensia 200 slidefilm >>> >>> >>> >>> X >>> >>> 5 >>> >>> Kodak Porta 400 NC >>> >>> X >>> >>> >>> >>> 4 >>> >>> Kodacolor Gold 200 Color Neg >>> >>> >>> >>> X >>> >>> 1 >>> >>> Kodak IR Ektachrome Prof >>> >>> X >>> >>> >>> >>> 3 >>> >>> Kodak Max 400 color neg >>> >>> >>> >>> X >>> >>> 10 >>> >>> Misc mixed single rolls >>> >>> X >>> >>> X >>> >>> *115* >>> >>> *Total rolls* >>> >>> >>> >>> >>> >>> Ken Lassiter >>> kenlass904 at gmail.com OR 561-247-7725 >>> >>> _______________________________________________ >>> Leica Users Group. >>> See http://leica-users.org/mailman/listinfo/lug for more information >>> >> >> >> > > _______________________________________________ > Leica Users Group. > See http://leica-users.org/mailman/listinfo/lug for more information -- Mark William Rabiner Photographer http://gallery.leica-users.org/v/lugalrabs/