"Impressione a secco" refers to embossing with no laminate: what is called "blind" embossing in English.

"Impressione a secco: disegno in bassorilievo realizzato senza ricorrere a lamine o inchiostri."
https://www.quickbags.it/faq/glossario-della-stampa.html

"1562 blind blocked; blind tooled; blanked; blind embossing — Embossed lettering on book covers which are not inked or gilded
impresso a secco; stampato in rilievo a secco; goffrato
1563 blind blocking — In bookbinding, impression by hot tools only, without gold leaf or ink.
stampa a secco; impressione a caldo alla pressa"
Dictionary of the Printing and Allied Industries
https://books.google.es/books?id=VQghBQAAQBAJ&pg=PA922

So "impressione a caldo in oro" means gold embossing and "impressione a secco" means blind embossing. In bookbinding the term "tooling" is probably best, but "blocking" or "embossing" would be correct too.



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Note added at 1 hr (2018-06-06 09:01:16 GMT)
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"blind tooling
A method of decorating a book in which impressions are made in the covering material, usually leather or tawed skin, by means of heated tools, pallets, rolls, fillets, or combinations of one or more of these. As the name implies, blind tooling does not entail the use of leaf metal, foil, or any other coloring material"
http://cool.conservation-us.org/don/dt/dt0366.html

"gold tooling
The art or process of lettering and/ or decorating the spine and covers of a book with GOLD LEAF (or, at times, other metals, e.g., platinum) impressed into the covering material, usually leather, by means of a heated letter, lettering pallet, or finishing tool. [...]
The universal adoption of gold tooling was by no means immediate, and, in fact, blind tooling was still the predominant form of decoration until about 1580, or even 1600."
http://cool.conservation-us.org/don/dt/dt1597.html

"Album re-bound (18thC/19thC) in brown leather with gold and blind tooling and gilt ruling, re-backed preserving original spine, containing 26 purple leaves with drawings inlaid with gold tooling,"
http://www.britishmuseum.org/research/collection_online/coll...

"Full leather three piece binding, spine stamped in gold, title blind stamped on front cover; gold and blind tooling."
http://www.sarahcreighton.com/bookbinding-25.html