Spraying negatives with varnish?

[chip j]

Paul Strand used to varnish his PRINTS.

 

[georgegrosu]

In cinematography there have been a number of treatments and procedures to reduce / eliminate film defects (scratches on the cellulose triacetate support).
For positive films, used intensely in projection, I know that in 1980 it was a fashion of lubrication of the positive.
The film was passed through a solution of perchloroethane in which high-pressure polyethylene was dissolved.
A thin film was placed on the film that lubricated the film and reduced the friction in the devices it was passing through.
The negatives scratched on the support were refurbished by polishing with acetone.
The scratched film is thoroughly cleaned by impurities (washing with perchloroethane in ultrasonic machines) and then polishing the holder on a crystal disc.
The crystal disk was moistened with acetone and the film was pressed onto the disk.
Acetone superficially dissolves the cellulose triacetate support and thus sticks to the disc.
The film took the perfect look of the crystal disc.
Films with polyester support can not be refurbished so the support does not dissolve in acetone.
Kino shows a machine from Photomec.
We had a simpler Polish machine from Poland.
To reduce the scratches on the support at copy - print / telecine, use the the wet gate.
Copying with the film immersed in a liquid having a refractive index close to that of the film support.
In this way, the light will no longer be deviated from the scratches on the support since the perchloroethane used has the same refractive index as the support.
By wet copy, the image quality increases.
The image has several black tones.

George