The stamps were a huge time investment, but surprisingly not terribly expensive once I finally ordered them. Not cheap, but I think less than 20% of the total cost.
Leather was the biggest raw material cost, probably 66% of the total. Though if someone does in fact order and buy another copy, that cost drops to about 33% of the total (leather order was enough for 2 books, so that doesn't keep decreasing with more orders).
Stamps should be able to be reused about 1000 times, so I'm not worried about those. I think each was used about 5 times, so unless I start to get close to 200 orders it shouldn't be an issue.
The rest is labour, and time. All subsequent books should be cheaper and faster. Unfortunately, whoever buys this 2nd book is saddled with additional costs. Twist my arm and I might let it go for $1200.
Future options to control costs would reduce the overall quality slightly, but I'm talking differences that only your elitist bookbinders would sniff at. I'm not kidding about 90%+ quality, 10% of the cost. (well, maybe a bit more than that, but at least 50% less).
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Further on dyes:
They dyes were made exquisitely, but the foil stamping process is too imprecise. Many of the finer details that I painstakingly recreated for the stamp came out perfectly in the metal, but when stamped came out muddled. I'm not too worried about it as it still looks great, but I might tool around with the files and see if I can't make something better.
This is also why I'd like to try laser etching. Should be more precise, and I can etch over a larger area (the whole cover), which should doubly help with the details. That, btw, was another limitation on the hot-foil dyes - the size I made is the largest that anyone was willing to do.