peterh5322 wrote:

But, no one makes variable density sound recoding film,

Yup! But if you can get enough light, 2234 dupe negative stock will
work. If you can't get enough light to expose D/N stock then finegrain
stock will work better than print stock, but the contrast is higher than
ideal.

nor do the labs know how to process VD properly.

A few still do, but it is a dying skill.

Earl.