[AV Media Matters] Answer about CTA support rejuvenation etc.

[e.ha.zwaneveld@nfb.ca]

Greetings,

Several weeks ago, Mick Newnham was looking for an article in Imaging
Technology. It dealt with CTA support, its convenient splicing and
rejuvenation with an organic solvent.

I received some answers from Dr. Karel Brems who wrote the paper in the
Imaging Technology Journal in March 1991, p. 94.

CTA is an abbreviation for Cellulose TriAcetate and is the support that is
traditionally used for motion picture film, except for print film and
intermediates which are today increasingly made of polyester support.

CTA continues to be used mostly for camera materials.

It can be rejuvenated reasonably easily by means of polishing of the
non-emulsion side, using a solvent, thus removing scratches. This
traditional method has been superceded in the last decades by solvent-based
immersion and application printing, by filling the scratches temporarily to
correct light refraction, thus making a scratch invisible during printing.
For chemical rejuvenation, methylene chloride is used, it is traditionally
also used in the pouring of the film base.

The article will be sent to me shortly, I will be happy to forward it to the
address Mick Newnham might care to e-mail to me.

Hoping to have answered the question,

Best regards,

Ed H. Zwaneveld,
Technological Research and Development
National Film Board of Canada