What he means is that they're multigrade insofar as they're
constructed with two layers of differing grade, resulting in
something that is in-between, but they're not multigrade
because the lack of sensitisers means that they're
sensitive only to blue, so their contrast is fixed.
Is there a set of formulae somewhere defining what each
of the grades means in terms of either their contrast
expansion/contraction or the number of stops
intensity they can encompass?
OK, now I get it.
Tables do exist. The values are the log ES ranges as
determined by use of a step tablet. Dan