Re: PHOTO-3D digest 1226

[harold lee tichenor <hticheno@xxxxxxxxx>]

William Carter wrote:> 
> The important difference being that because
> of the extreme latitude of these films, they have a light absorbing
> carbon deposit on the substrate. Your average lab isn't set up to remove
> this, but if you do your own then it is easily removed with a wipe of a
> sponge or squeegee.Motion picture stocks have an anti-halation backing because the gates in 
motion picture cameras are highly polished metal to allow the film to pass 
through at speeds exceeding 90 feet per minute.  The pressure plate can not 
be black as it is in still cameras because the coating would wear off with 
the hundreds of thousands of feet of film that pass over it during its 
lifetime.  This backing is washed off in the first stage of the lab's 
processing.  

If you are doing this by hand (in the dark!) it is important that the film be 
rinsed well since the backing leaves particals in the wash water.

I am surprised at the short life span reported in previous digests for 35mm 
motion picture stock.  I have been shooting negative colour film stocks in 
35mm motion picture cameras for over thirty years and in 16mm since the 
introduction of 7247 in the 1970's replacing the old reversal ECO.  We still 
make occasional prints from those old negatives which do not appear to show 
any signs of aging.  Our negatives are vaulted according to Kodak's 
published standards.

Nevertheless, the motion picture industry still occasionally uses the old 
tricolour separation master process ( creating registered YCM black and white 
masters) for extreme long term archival storage.  Black and white negative 
and interpostive stocks are supposed to have a projected life span if 
properly stored of five hundred years!  

Regards
Harold Tichenor



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