Possibly the masterpiece of color printing in oil colors from woodblocks by the Leighton Brothers, George Cargill Leighton and Charles Blair Leighton, was
Gems of English Art of this Century: Twenty-Four Pictures from National Collections, Printed in Colours by Leighton Brothers. With illustrative Texts by Francis Turner Palgrave. Burch,
Colour Printing and Colour Printers (1910) 148-149 calls the plates in this work "excellent productions, that would probably be 'collected' if they bore Baxter's name instead of Leighton's....Judging from the point marks on the side of the print, Constable's 'Valley Farm' required twelve blocks for its reproduction."
The first original cloth binding (Variant A) that I am illustrating with this entry is one of my personal favorites. Printed in four colors plus gold, it may have been designed by John Leighton. Was binding variant B also designed by Leighton?