Stop-Out Varnish: Turpentine and Resin with Lampblack (Spon's Workshop Receipts)

The etcher's stopping-out varnish from Spon's Workshop Receipts: resin dissolved in spirits of turpentine in a warm water bath, coloured with a little lampblack, and brushed over the parts of the plate that must not bite further. Spon rates it better than Brunswick black; it sets hard overnight and can be thinned again with turpentine. Source: E. Spon, Workshop Receipts (first series), pp. 155-156. Picture: the book's text.