Bio-inks for books. (is "100% bio" possible?)

After my trip to the Frankfurt Bookfair (a bit less people than last year, many books as usual, much more e-book-reader devices - mainly Korean -, and big announce by Google that will start selling digital books in 2010) here we are, back to our beloved eco-friendly paper-made books.

As sayd in the previous post, NAPIM has invented something really simple, and - as all the very simple things - brilliant.
They have invented the BRC Index for printing inks.
Each ink will have, in their purposes, a BRC Index.
BRC 40? Means that the ink XY is made with 40% of renewable materials (vegetable materials, mainly).
BRC 60? Means that the ink ZZ is made with 60% of renewable materials. (see the image)
There is also a complete list of these bio-derived materials, in the NAPIM website.
Very simple and very clever.
This BRC Index is a great idea, in my opinion. It will improve competition between ink manufacturers. And it will be easier to know how much eco-friendly an ink is. (Because, you know, it is not enough that you ask for an ink with some vegetable materials inside. You must know how much of them! Many printing inks have, for example, some vegetable oils, but they can have also mineral oils - petroleum - and so their BRC is still low, maybe 30 or 40!)

BUT. Is it possible to reach a BRC 100?
Yes and no.
The ink (the one for offset sheetfed machines, the most used for books) is made of: oils, resins, pigments, additives.
In the so-called "vegetable-based" inks, just oils and resins are vegetable (and renewable).
As oils and resins are the bigger part of the printing-ink, you can reach a BRC 70, maybe 80, just using vegetable oils and resins.
But pigments (the colours) and additives (most of them) are chemical.
It would be possible to use vegetable pigments? Technically yes. But the colours would be less brilliant, experts say. (Anyway, I would like to have at least one ink made with vegetable pigments! Remember: Books Like Flowers! Ink manufacturers: please, take note!)
And not using chemical additives (because some of these additives are not very good for the environment)? Experts say: no. (Well, I am not a chemist, but I know that some chemical additives are  necessary just to let the printing machines work faster and faster. So they are not really necessary. There are always greener solutions!)