What is this woodcut / engraving like / illustrative design style called? (as seen on the US dollar sign)
Where can I find books / references / inspirations to learn the principles behind these graphic patterns?
It's often seen in luxury or heritage style products, as well as the us dollar sign. What is the art or graphic design style called? I understand that this may be a mix of various styles, but is there an overlapping or overall name for this art style?
Specific examples include Simon Frouw's work as they all seem to fall under this category:
Looking at them they just look elegant and old-school luxurious with all the intricate details that looks hand crafted. From looking at the various examples I gathered there seems to be elements or art deco geometric patterns, halftone engravings styles, monograms, and heritage crests
I'm probably the most interested in the beautiful decorative geometric & illustrative or graphic design patterns as seen in the background.
What's the principle behind these designs? What's it called and where can I learn to make them?
As for the 'style' you see on printed US Currency, that is engraving. It's more of a technique than anything. See the answer here.
That said, the samples show aren't all engraving. A few borrow (namely 'A' monogram) but you have other techniques and styles going on.
The first two are just decorative illustrations. They are evocative of a lot of late 1800's style advertising.
The 3rd we discussed, and is the closest to engraving.
The 4th is emulating hand lettering--specifically gold plated signage. Also something you say a lot of in the late 1800s into the 1900s. It was traditionally done in gold leaf and paint on glass. There's also decorative type swashes included.
The last is physically embossing (raised decoration) and stylistically perhaps best described as 'playing card style'.
I wouldn't call any of the styles shown as 'woodcut'. That's perhaps related, but tends to have a bit of a different aesthetic.