Perhaps I mispoke when I said "silver" when I should have said "silver halides"? But Kodachrome and b&w negatives neither one allows me to use the infra red dust removal tool of my film scanner, and the reason often given by various sites is that the problem is due to their silver based emulsions.
Like this from a <
SilverFast website> "
Kodachrome slides are very challenging to scan due to the silver halides this film material is containing. Most scanner software produce blue casts and infrared dust and scratch removal always fails with Kodachromes. The Nikon CoolScan 9000ED, featuring an advanced version of Digital ICE®, was the only device capable of removing dust and scratches from Kodachromes … "
Or this from <
ScanTips> "
The Infrared channel does not work with B&W film because the silver content blocks all light equally (and infrared will want to remove anything it sees). Kodachrome slides are silver-based too, and processing sometimes leaves some of the silver in it, so it can become partially visible in infrared too."
And <
this one> "
Kodachrome film contains similar substances (for example silver) that are also contained in black and white films and are impermeable to an infrared ray. The ICE proceeding fails with such kinds of particles."
This may be another example of something that "everybody knows" not being factual? I don't understand the chemistries well enough to say if these statements are true or false. I will defer to your greater knowledge on this subject. I was only repeating something I had often read on the internet.
But I think we can agree that, for whatever reason, the infra-red dust removal tools provided by some scanners often does not work with black & white negatives or Kodachrome slides. Yes? No?
Subject to one qualification, we can agree that infra-red dust removal tools don't work with black & white negatives or Kodachrome slides.
One of the people who posts regularly on Photrio believes that his version of Nikon (IIRC) scanning software does permit use of infra-red dust removal with Kodachrome, but I've never heard that from any other source.
I'm afraid those sources you have quoted misunderstand the reasons why ICE doesn't work with Kodachrome.
It is true that Infra-red dust removal doesn't work with traditional black and white negatives because of the silver retained in them.
However Infra-red dust removal doesn't work with Kodachrome slides for another reason - the thinness of the emulsion and the resulting physical relief of the surface of the slides. If you have never looked at a Kodachrome slide's surface carefully, you should. It isn't flat - the surface goes up and down in relation to the relative presence of the image forming colour dies. It is like one of those globes where the mountains and oceans are shown in both colour and in differing amounts of raised relief.
By the way, there are no silver halides left in a properly processed Kodachrome slide - if there were silver halides remaining in the Kodachrome slides after development, Kodachrome would have terrible keeping properties.
And that qualification I mentioned? Infra-red dust removal software does work with the chromogenic black and white films like Ilford XP-2 Super - the ones designed to be developed in colour chemistry. That is because the C41 process includes a bleach step that eventually results in all the silver being removed, leaving just dies.