On Jun 3, 2016, at 3:31 PM, Tracy Valleau <tracy@...> wrote:

Hi Mark, and welcome! We're delighted to have you and your skills aboard :-)

As to the question:

First - I do not have direct experience with the problem, but that won't stop me from a bit of conjecture...

I suspect that the texture is too large to make de-noising software fruitful...

Then I thought about wetting the image, but realized promptly that's not likely practical with old prints.

My final thought was to dump the scanner and try photographing the image with a high-res camera, such as a D800, with a ring light on the lens.

I'm afraid that's it. Should I have an "aha!" moment, I'll post it.

Perhaps others here have run across the problem, unlike me, and will have a solution for you.

Tracy
www.valleau.gallery