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Collotype plate problem back in 1922

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Altamura:
I agree that these scratches must have been on the plaster casts.

At least for some of these coins you can see on more recent pictures that scratches seen in the auction catalog are not on the coins:
lot 195: https://www.acsearch.info/search.html?id=8592160
lot 94: https://www.acsearch.info/search.html?id=5571469
lot 62: https://www.acsearch.info/search.html?id=3420024
lot 200: https://www.acsearch.info/search.html?id=1824822  (some scratches are on the coin, some not :) )
lot 220: https://www.acsearch.info/search.html?id=1297096

And at lot 105 you can see a cast with a bad nose surgery  :): https://www.acsearch.info/search.html?id=1002785

(You find the Naville IV catalog here: https://digi.ub.uni-heidelberg.de/diglit/kundig_naville1922_06_17/0003 )

Regards

Altamura

dwarf:
I produced a few thousand plaster casts in my former life as student and have no idea how these scratches came into being.
But I have no other solution
Regards
Klaus

Steve Moulding:

--- Quote from: Altamura on January 11, 2022, 03:55:43 am ---:
At least for some of these coins you can see on more recent pictures that scratches seen in the auction catalog are not on the coins:
:

--- End quote ---

Wow! That's brilliant. Thanks so much for tracking all those down. In the Akragas Didrachm (attached) you have found a great example...real scratches plus 'process artefacts' (for want of a better term). 

I think it's possible, though perhaps unlikely, that they (Naville) experienced multiple problems along the way with that catalog. What look like wider furrows on a small number of lot images, such as 103 (shown earlier), may be collotype or plaster issues, and the very fine lines may be scratches on the negatives, per Ron's theory. For lines, cracks or furrows in plaster, I would rely on your, Curtis' and Klaus' experience and expertise to say what is and is not possible.

Now if there really were several disjoint issues at play, then it seems unlikely they would all get fixed at the same point in the catalog. We could then expect to see either furrows and/or fine scratches after Plate VIII. If all later plates are clean, I think it was likely a single issue. I need to go through the later lots to confirm.

Thanks again, everyone.

Steve

Steve Moulding:

--- Quote from: STEVEN M1 on January 10, 2022, 04:52:03 pm ---:
Another thing comes to mind. If these were super long scratches across a single large negative, shouldn't we expect to see scratch continuity across adjacent lot images? That may be present, but so far I don't immediately see a good example of it.
:

--- End quote ---

Well, I think that's it. Very likely long continuous scratches on the plate that can sometimes span more than one lot. Attached is a quick example from Plate VII. Only some scratches are highlighted for illustration, and apologies for my poor artwork...it's a simple image editor. Both wide (furrows) and fine scratches are present on the plate. It then doesn't appear to be a plaster issue. Also, later Plates IX-forward look clean.

The illustrated scratches do have some curvature. Perhaps negatives being put in / taken out of a dusty open-side flat folder multiple times in an arc-like movement? That's my best guess (but harder to see how that would cause the wider furrows).

Steve

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