Woolnough says of Indigo under the heading The Colours Used in Marbling
"This colour is a most valuable article, and cannot be dispensed with under
any consideration. The East India or Bengal is the best. It is too well
known to require any description here. Though not a bright colour, it is
one of the most durable; and for mixing and producing greens and purples of
a permanent kind is invaluable, neither can you make a good black without
it; but be sure you obtain it good."
The only information Woolnough provides re marbling cloth is the reason for
the demise of the product
......"it was received with the most cordial approval and orders to a large
amount were promised, but .................those in whose hands the control
and management, or rather mismanagement, was vested, thinking that from the
great demand for the article they could command any terms they thought
proper to exact, proceeded to impose such arbitrary terms that the trade in
general turned against it, and a reaction took place which they were not
able to hinder or check, and a patent having been taken out, not only for
Great Britain but also for other countries, it resulted in a loss."
There is no specific entry about the indigo being used in marbling the
cloth, and no specific methods. However one would think if he valued the
indigo so highly, he would have used it
for marbling book cloth. He mentions that a manufacturer of book cloth
tried printing marbled designs (to avoid infringement of the patent) but
the results fell far behind the hand produced article.
The only advantage being that large lengths of cloth could be produced,
instead of a "yard or two in length at most".
Hope this answers your question Jake.