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RE: New to Telecine and your gr



>Martin Banks[SMTP:martin_banks at qm1.mvbms.com] asks:
> Would someone be kind enough to tell me what a wet gate is?

During printing, or on telecine, light passing through the negative is
scattered (refracted) by any scratches in the surface of the film: this
shows as white marks on the print or video image.

By immersing the negative in a fluid with the same refractive index as
the film base, the light scatter is eliminated.

In contact printers, the entire printing head is immersed - gate,
negative, rawstock etc.
 
In projection printers or telecine gates (not many used these days as
digital dirt removal is seen as superior to optical technology??), the
negative passes through a gate that is similar to a glass slide mount,
filled with the fluid. A circulation system keeps the fluid refreshed
and prevents it from leaking out with the negative as it emerges.

The fluid is usually tetrachlorethylene, which as the required
refractive index.

Labs tend to print ALL final cut original negative (certainly 16mm),
using wet gate, as cut negative invariably has a smattering of handling
marks. Also, contact printers seem to benefit from the system giving a
sharper result.

Contrary to many beliefs (and quite clearly when you think about it),
wet gate does NOT remove dirt. It only works with scratches or cinches.
(Strictly it doesn't remove them either, it only makes them invisible.

~~~~~~~~~~~~~~~~~~~
            Dominic Case   
            Atlab Australia   
 ~~~~~~~~~~~~~~~~~~
>

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