Author Topic: Zeng Chenghu discussing coin dies including those for pagodas and goldfish  (Read 19924 times)

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Offline fwang2450

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Mr. Zeng Chenghu, director of the Die Manufacturing Dept. of Shanghai Mint, is currently discussing hand-engraved dies on bqcoin.com. Here is the link:

http://bbs.bqcoin.com/read-htm-tid-4867-page-4.html

The discussion covers medals from Shanghai Mint, pagodas and goldfish included. Those who know Chinese can register and participate in the discussion directly. For those who do not know Chinese, Google Translate may help with the discussions (but not the mail post, which is made up of graphics files). Or I can help to translate and post your questions. He is very nice and responds to every question.

Offline SANDAC

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Re: Zeng Chenghu discussing coin dies including those for pagodas and goldfish
« Reply #1 on: September 18, 2014, 12:49:49 AM »
Good discussion.  So let me see if I got this right:
1.  A hand engraved die is where the designer carved the original design 1-to-1 on to a master die(祖模)
.  The master die is used to produce working dies.  When a working die is worn out, a new working die can be produced from the master die.  So the hand engraved die making process eliminated the 10x original design and the 10-to-1 pantograph reduction process, presumably to save cost and time.
2.  There are special knowledge and artistry associated with making of the working die from a master die, so even with the same master die the quality of working dies may vary.
3.  Repair of the working dies are production issues and the original designer may not be aware of.

Mr. Zeng mentioned on his last post that (original text: 古塔剪影图案的一面是用铜版(即把图案腐蚀在铜版上)在立雕机上雕刻的,而不是手工直接钢刻的,包括金鱼剪影的一面也一样。如果再版和原版有较大差异,那么此面有可能是重新雕过的,因为这是生产和销售的事,他们不必通知原作者。) the silhouette of pagoda side (SANDAC's question: the reverse side?) was done with etched copper plates, not hand engraved steel die.  This is also the case with the reverse of goldfish.  If there are significant differences then it may due to redesign (SANDAC's question: as in a new master die?) and were production/sale decision not involving the original designer.  An intriguing comment since it is the reverse of the brass/silver/gilt/silver-plated pagoda that have most readily discernable differences.

Offline fwang2450

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Re: Zeng Chenghu discussing coin dies including those for pagodas and goldfish
« Reply #2 on: September 18, 2014, 01:20:36 AM »
Good discussion.  So let me see if I got this right:
1.  A hand engraved die is where the designer carved the original design 1-to-1 on to a master die(祖模)
.  The master die is used to produce working dies.  When a working die is worn out, a new working die can be produced from the master die.  So the hand engraved die making process eliminated the 10x original design and the 10-to-1 pantograph reduction process, presumably to save cost and time.
2.  There are special knowledge and artistry associated with making of the working die from a master die, so even with the same master die the quality of working dies may vary.
3.  Repair of the working dies are production issues and the original designer may not be aware of.

Mr. Zeng mentioned on his last post that (original text: 古塔剪影图案的一面是用铜版(即把图案腐蚀在铜版上)在立雕机上雕刻的,而不是手工直接钢刻的,包括金鱼剪影的一面也一样。如果再版和原版有较大差异,那么此面有可能是重新雕过的,因为这是生产和销售的事,他们不必通知原作者。) the silhouette of pagoda side (SANDAC's question: the reverse side?) was done with etched copper plates, not hand engraved steel die.  This is also the case with the reverse of goldfish.  If there are significant differences then it may due to redesign (SANDAC's question: as in a new master die?) and were production/sale decision not involving the original designer.  An intriguing comment since it is the reverse of the brass/silver/gilt/silver-plated pagoda that have most readily discernable differences.

A couple of corrections:

1. A hand engraved master die has a negative image on it, unlike the master hub from the reducing machine. So a working hub has to be made from this master die, and then working dies made from the working hub. Working dies for restriking coins later on are supposedly made from the working hub, not the master die.

2. Hand engraving is a long and tough process. It is said that it took the Shanghai Mint engraver Bai Wenjun almost a year to hand engrave all the 8 sides in the Plum, Orchid, Bamboo and Chrysanthemum set. So engraving dies by hand is not for the purpose of saving money or time. Rather it is to showcase their skills and mastery of the art. The tails of goldfish are simply amazing if examined under magnifiers, so are the details of the Guilin Landscape medals.

What Mr. Zeng points out sometimes is common sense, but only known to the mint people, such as the skills involved in each step of die making, and die touching up by junior engravers either during die making or die repair. Yet the work of these junior engravers may result in differences among the products struck, or varieties.

It is interesting to know that the reverse side of pagodas and goldfish were not hand engraved, but produced on a milling machine. That explains a few things, such as the inverted v shapes on the S lines on pagoda's reverse. I was going to ask him how it was possible to make these lines by hand.

Offline fwang2450

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Re: Zeng Chenghu discussing coin dies including those for pagodas and goldfish
« Reply #3 on: September 18, 2014, 01:29:47 AM »
Here is a picture of the hand engraved goldfish, from RAREMEDAL. The hand engraving cuts on the tail of the goldfish are very visible. (The horizontal lines in the lower part of the tail are cracks in the capsule.)



Offline fwang2450

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Re: Zeng Chenghu discussing coin dies including those for pagodas and goldfish
« Reply #4 on: September 18, 2014, 01:42:31 AM »
Details of a medal from the Guilin Lanscape set, which is 27 mm (a little more than an inch) in diameter. Hand engraved by the former director of Die Manufacturing Dept. of Shanghai Mint, Fang Maosen:


Offline pandamonium

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Re: Zeng Chenghu discussing coin dies including those for pagodas and goldfish
« Reply #5 on: September 18, 2014, 08:27:53 AM »
I could not open the link so did forward it to another collector to send back to me.   Could you list the MCC w/ hand engraved dies?   The details are terrific.   These MCC should see high demand as we go forward........

Offline fwang2450

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Re: Zeng Chenghu discussing coin dies including those for pagodas and goldfish
« Reply #6 on: September 18, 2014, 11:43:50 AM »
I could not open the link so did forward it to another collector to send back to me.   Could you list the MCC w/ hand engraved dies?   The details are terrific.   These MCC should see high demand as we go forward........
I will provide a list later on. But please be aware that these hand engraved pieces are all medals, not coins. It is not possible for the engraver to spend months hand engraving a die of a coin, as coin production has to meet certain schedules. As pieces of art, they are top notch, but it does not mean they are the best investment in MCC. I am collecting these hand engraved medals, mostly brass, because I like them, not because of their investment potential. I actually feel relieved when I collect such medals as I do not have to think about their returns. 

Offline poconopenn

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Re: Zeng Chenghu discussing coin dies including those for pagodas and goldfish
« Reply #7 on: September 18, 2014, 05:08:58 PM »
Here is the process in make production die.

Hand-crafted or machine milled die (positive image)---> master die (negative image)---> working hubs (positive image)---> Production dies (negative image)---> coins (positive image).

Depending on the mintage of coin/medal, multiple of working hubs may be made in order to make enough production dies for minting the coins.

Master die, as mentioned by Mr. Zeng, does not use as a production die in minting process in any Mint, except counterfeiter who copies coin/medal (positive image) to make master/production die (negative image).

Offline poconopenn

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Re: Zeng Chenghu discussing coin dies including those for pagodas and goldfish
« Reply #8 on: September 18, 2014, 05:26:16 PM »
Fwang,

When you ask Mr. Zeng about 本铜 (copper) pagoda set as in your post (attached), I assume this is not brass set. Do I correct? Brass is yellow copper in Chinese.  

 尊雅
 
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只看该作者 地板   发表于: 09-13
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引用第2楼fwang2450于2014-09-12 23:41发表的  :
手雕工艺的总结之作,信息量真大,很多都是第一次了解。慢慢看,慢慢记,慢慢问,慢慢收。

先想问先生1个问题。四大名楼章市面上都是镀金的,是否有本铜版的?

 

本铜版的没有生产过

Offline fwang2450

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Re: Zeng Chenghu discussing coin dies including those for pagodas and goldfish
« Reply #9 on: September 18, 2014, 06:12:55 PM »
Fwang,

When you ask Mr. Zeng about 本铜 (copper) pagoda set as in your post (attached), I assume this is not brass set. Do I correct? Brass is yellow copper in Chinese.  

 尊雅
 
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引用第2楼fwang2450于2014-09-12 23:41发表的  :
手雕工艺的总结之作,信息量真大,很多都是第一次了解。慢慢看,慢慢记,慢慢问,慢慢收。

先想问先生1个问题。四大名楼章市面上都是镀金的,是否有本铜版的?

 

本铜版的没有生产过

本铜 here refers to solid brass, in contrast to gilt or silver plated brass. As far as I know, the material for early small size medals was brass, not copper. 本 here is used as opposed to gilt/silver plated.

The question was not about pagodas, but the famous towers, as shown in the pictures below. As they are gilt, with a line-art kind of design, they have not been popular. But this was the first time I had learned that the set was hand-engraved, too.

Offline fwang2450

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Re: Zeng Chenghu discussing coin dies including those for pagodas and goldfish
« Reply #10 on: September 18, 2014, 06:26:50 PM »
Here is the process in make production die.

Hand-crafted or machine milled die (positive image)---> master die (negative image)---> working hubs (positive image)---> Production dies (negative image)---> coins (positive image).

Depending on the mintage of coin/medal, multiple of working hubs may be made in order to make enough production dies for minting the coins.

Master die, as mentioned by Mr. Zeng, does not use as a production die in minting process in any Mint, except counterfeiter who copies coin/medal (positive image) to make master/production die (negative image).

The hand engraved die has a negative image, not a positive image. So it is a die (negative). The master hub produced by the reducing machine has a positive image, which has to be pressed onto the master die.

Hand engraved dies have fewer steps in their making, removing clay, negative plaster, positive plaster, electrotype and reducing from the die making process.  So the image quality and details are better preserved.

Offline SANDAC

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Re: Zeng Chenghu discussing coin dies including those for pagodas and goldfish
« Reply #11 on: September 18, 2014, 08:17:55 PM »
I'm interested to know at what point of the die making process the Chinese characters are created, and when date/denomination are created.  We know in panda, different mints usually have different size date, so date is certainly put down at different time.  However, there are also large number of varieties with shifted or different size Chinese characters, much more frequent than different graphic designs, so I think Chinese characters were also added later.  I wonder if Mr. Zeng can shed some light on the sequence of creation for the Chinese characters, denomination and date with respect to the graphic designs.

Another curiosity is die rotation of obverse with respect to reverse.  Frequently there are 2, 3, or even more die rotation in a MCC.  Vast majority of them are too minor to be considered as mint error, but they are definitely there and quite common.  Shouldn't there be an integrated index key when a die is created?

Offline poconopenn

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Re: Zeng Chenghu discussing coin dies including those for pagodas and goldfish
« Reply #12 on: September 18, 2014, 08:45:04 PM »
The hand engraved die has a negative image, not a positive image. So it is a die (negative).

This is news to me.  You are suggesting that Chinese artists are so good that they can use chisel and hammer to make a negative image of the design in a hard steel blank. This is also very different from the process in other mints.

Offline fwang2450

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Re: Zeng Chenghu discussing coin dies including those for pagodas and goldfish
« Reply #13 on: September 18, 2014, 09:07:56 PM »
This is news to me.  You are suggesting that Chinese artists are so good that they can use chisel and hammer to make a negative image of the design in a hard steel blank. This is also very different from the process in other mints.
This is from Mr. Zeng's mini blog:

“手雕的制作方式是:把图稿缩至产品大小→用榔头、凿子、雕刻刀在落样的钢料上一比一的雕刻(一般是雕刻阴纹)→模具淬火→压印产品。如果阴纹雕刻有失误或是图案中有阴阳图案的话,还需有翻制阳纹、阴纹模具的二次雕刻与修改的反复。”

一般是雕刻阴纹 means "generally a negative image is engraved".

From my reading of Walter Breen's Dies and Coinage, hand-engraved dies were negative from the very beginning of Western coin making, as the image on the coin was positive. Later on either positive or negative images were hand engraved. But as far as I know, Shanghai Mint engravers worked on the negative images. If you read his main post (image page 62), he made this point very clear. So apparently the Chinese artists are as good as ancient artists before hand engraving was used to make hubs.  :001_smile:

Offline fwang2450

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Re: Zeng Chenghu discussing coin dies including those for pagodas and goldfish
« Reply #14 on: September 18, 2014, 09:20:14 PM »
I'm interested to know at what point of the die making process the Chinese characters are created, and when date/denomination are created.  We know in panda, different mints usually have different size date, so date is certainly put down at different time.  However, there are also large number of varieties with shifted or different size Chinese characters, much more frequent than different graphic designs, so I think Chinese characters were also added later.  I wonder if Mr. Zeng can shed some light on the sequence of creation for the Chinese characters, denomination and date with respect to the graphic designs.

Another curiosity is die rotation of obverse with respect to reverse.  Frequently there are 2, 3, or even more die rotation in a MCC.  Vast majority of them are too minor to be considered as mint error, but they are definitely there and quite common.  Shouldn't there be an integrated index key when a die is created?
In his reply to my question about dates, Mr. Zeng mentioned that dates were added later on, on the plaster or hubs/dies, but not on the clay model. What Chinese characters do you have in mind? Can you give an example, so that I can ask him?

I am not clear about your question on die rotation either. But please beware that he is not involved in production. If you are talking about the alignment of the reverse vs the obverse, I assume he would not exactly know. Anyway such die rotations are common from all mints, I assume?