I received a really amazing gift yesterday--all the original casts from Keith Rutter's HN Italy! I'm over the moon with joy, and today the casts for Campanian Coinages are due to arrive. What an honor to be their custodian. I've already learned so much reassembling them. There's just something about a 3D copy that even the best photos can't match.
Pretty cool! But, I'm not exactly sure about what they are Did the author of this book have forms made of all the coins pictured? And these are the casts? You said that these are the originals, do the forms still exist? Seems like a good idea, but I didn't realize that authors did this type of thing.
The forms are just from a piece of clay that is reused as you make a bunch of plaster casts of each coin you need.
No, just a lump of clay, then you take the coin and make an impression, then fill the impression with plaster. Once the plaster dries you pop it out, knead the clay, and you're ready to make a new impression of a different coin.
This is actually how the plates were made in most older auction catalogues especially in the first half of the 20th century and many references as well(and before that it was often line drawings). Plaster casts are great because they tend to be much easier to get good photographs of than metallic coins themselves, and sometimes fine details you wouldn't necessarily see in a coin photograph due to toning or other surface conditions stand out better in casts(though also sometimes detail is lost in the process). Here's an example of a coin of mine, how it looked in photograph in a major auction last year and how it appeared in a catalog from 1930 in a plaster cast: Some fine details such as the border circle at 10 o clock on the reverse are more pronounced in the cast. Notice how it appears to end at the tip of victory's wing in the modern photo but extends a bit further in the 1930s plaster cast. The border of dots on the obverse on the other hand looks a bit strange, I believe due to air that could get trapped in those small dots during the casting process, a pretty common defect you see in reproduction via plaster casting. Some of the little minor cracks and surface imperfections basically disappear in the plaster cast as well - perhaps not the best thing for coins selling at an auction but you don't care about that sort of thing when you're looking at a reference like Historia Numorum Italy and looking at details to learn rather than deciding how much you want to bid. You can see the alternative here, a contemporary auction that used photographic plates. The coins in that post are beautiful but the photos from 1938 are horrendous.
