Ron - all the pigments used in any of the commercial carbon or carbro processes would be classified as opaque. They allow light to pass around
them because the dispersion is relatively thin. But the ability to hypothetically make true transparent process pigment is relatively new
technology. There are a couple of ways to do it, but all the carbon printers in the world would not be enough incentive for a manufacturer to make money on a custom batch. Somone would have to finance it just for the love of the medium. Inkjet pigments are really complex blends of dyes,
pigments, and lakes. But permanence is not their first priority. You can learn a lot about them from the underlying patents. The bigger issue is
dispersant technology, and here there are some serious trade secret involved. Given all the added ingredients in inkjet colors, it probable they'd
do poorly in a carbon or carbro application. What I'd really like to see is
the kind of glow one gets with a dye transfer print with the permanence
and scale of a carbon. The clues are out there, but probably not in photographic literature per se.