The batiked vellum bindings of the fin-de-siècle may be unique in their blend of Eastern technique with Western style, the extensive decoration of vellum in itself was not invented in this period. Although I have not yet seen much attention to it in bookbinding specialist books, there has certainly been a wave of painted vellum bindings. I have seen several Dutch examples during the past few years in auctions (alas, no pictures for now), and it seems to be a personalised trait in protestant Christian works. While the Protestant wing is for me most known for their black 'sharkskin' bibles with eleaborate silverwork (on which a beautiful book is written by Bernard van Noordwijk: De erfenis van Kortjakje - in Dutch), there certainly has been a fine and personal way of decorating religious books, maybe inspired by the baroque (but still deeply devotional) Pietist works that were made and published in Germany during the same time.
Most of these bindings feature a central gilt emblem (stamped but not from a clear mould, as front and back sides often slightly differ) and floral motifs (mostly in red). Of course the silver (double) clasps would not lack on such special bindings.
The colours that were used feature a distinct yellow (more yellow than the usual blank skin colour), the green that was also used for almanac bindings, and fiery red for the flowers.
I hope to collect more definite material, including images.
As usual: hopefully to be continued.