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Optic Molds

One of the most fascinating aspects of glassblowing is that the fundamentals and basic tools have not changed for many centuries, even millenia.
 
I am indebted to the research librarians at the Rakow Research Library at Corning Museum of Glass for helping me research the very early history of optic molds.
 
Hrabanus Maurus - De Universo - 1425 - Vatican Library
Although the image above was scanned from a French book (hence the French subtitle), the original, in the Vatican Library, is De Universo by Hrabanus Maurus (Rabanus Maurus), written in Latin, as well as translated into German, and dated 1425.
 
Consider that this predates the invention of the printing press by Johannes Gutenberg around 1440!
 
It is clear to me that there is an optic mold closest to the left foot of the glassblowing in this image, you can see a bit of vertical lines at the top of that optic mold. If you look at the full-size (6.0 MegaByte) image (by clicking above), I would suggest that you are looking at a 10-Point or 12-Point optic mold, since at least 5 vertical mold lines are clearly visible.
 
The French text has more to say about this:
French
======
Fabrication du Verre.
Manuscrit Du << De Universo >>
Sur ce manuscrit de 1425, les formes des trois pieces achevees
qui se trouvent aux pieds du verrier sont tres differentes
de celles qui figurent sur le manuscrit de la bibliotheque du Mont Cassin.
BIBLIOTHEQUE VATICANE
English
=======
Manufacture of Glass.
Manuscript Of << The Universe >>
On this manuscript of 1425, the shapes of the three parts achevees (?) who are at the feet of the glassmaker
are very different those which are reproduced on the manuscript of the library of the Cassin Mount.
Vatican library
What is interesting is that the book "Renaissance and Renascences in Western art" By Erwin Panofsky, American Council of Learned Societies, Published by Harper & Row 1969, states that the 1425 book is a German copy after a Carolingian Manuscript, which would seem that the origins of this could be much older. That image can be found here.

 
The image below is scanned from De Re Metallica by Georgius Agricola, 1556 (page 476)
It clearly shows two glassblowing molds (labelled "E") on the floor near the furnace.
De Re Metallica by Georgius Agricola - Page 476 - Glassblowing - Optic Molds on Floor
(click for full-size 6.8 Megabyate image)

The Columbia Encyclopedia (Sixth Edition, 2008) has this to say about Georgius Agricola:
Georgius Agricola, Latinized from Georg Bauer, 1494-1555, German physician and scientist,
known as the father of mineralogy. He was a pioneer in physical geology and the first
to classify minerals scientifically. His celebrated work De re metallica (1556)
was a standard in metallurgy and mining for over a century and was translated into
English (1912) by Herbert C. Hoover and Lou H. Hoover.

 
There are two optic molds, labeled "E", in the image above:
  • The upper optic mold in the image appears to be a 9-point star optic mold
  • The lower optic mold in the image appears to be a 5-lobed (rounded lobes) optic mold
De Re Metallica by Georgius Agricola - Page 476 - Glassblowing - Close-Up of Optic Molds on Floor
In the original Latin text, "E" is stated as:

"Instrumenta quibus formae sunt datae"
In Hoover this is translated into English as

"Moulds by means of which the shapes are produced"
 
Click here if you would like to see Agricola's image above as printed in Hoover's 1912 English translation, with English subtitles.

 
Antonio Neri's L'Arte Vetraria dated 1612 shows a very similar (Figure IV) to Agricola
In fact, Neri has the SAME TWO OPTIC MOLDS still shown as "E"

and I note that in Neri we have an 11-pointed star optic mold and a 6-lobed optic mold
although due to the irregular spacing of the star points,
I would guess it was really as 12-point star optic mold,
to give even 30-degree increments around the circumference.

 
A very similar (Figure Q) appears in Kunckel 1756 (page 299):

"Die Instrumenten darein man formen geust."
which translates into English roughly as
"the instruments thereon one shapes"
but note that the star optic mold in Kunckel is a much clearer 8-pointed star,
although the lobed mold appears less well defined.

 
If you look around any glassblowing studio ("hot shop"), especially around the marver, which typically has at least one shelf inside it, you will almost certainly find OPTIC MOLDS of many different shapes and sizes.

Steinert Industries appears to me to be the premier manufacturer of glassblowing Optic molds, with a mind-bogling variety of shapes and sizes.

Please note that I have no financial interest or motivation in recommending Steinert Industries but it is my personal belief that they are an extremely quality company providing excellent glassblowing tools at reasonable cost.

There are many other optic molds sold which are smaller than 4" tall, these are often used in lampworking / bead-making, and are not included on this web page.

p.s. I created this Optic Mold web page after completing my Fin Mold web page,
and realizing that I had not created a web page for the much more readily-available optic molds,
so I correct that oversight with this web page.


 
(Clicking on any of the images or links below should take you directly to a web page with more information concerning that particular optic mold)
 
Company Series/Size Points/Ribs Bottom
A = Open / B = Closed
Photo Description
Steinert Industries4"20A = Open  4-1-20A - Steinert Optic Mold for Glassblowing   4-1-20A - Optic Mold for Glassblowing 
Steinert Industries4"5A = Open  4-10-5A - Steinert Optic Mold for Glassblowing   4-10-5A - Optic Mold for Glassblowing 
Steinert Industries4"HeartA = Open  4-11A - Steinert Optic Mold for Glassblowing   4-11A - Optic Mold for Glassblowing 
Steinert Industries4"12B = Closed  4-12-12B - Steinert Optic Mold for Glassblowing   4-12-12B - Optic Mold for Glassblowing 
Steinert Industries4"8A = Open  4-13-8A - Steinert Optic Mold for Glassblowing   4-13-8A - Optic Mold for Glassblowing 
Steinert Industries4"16A = Open  4-14-16A - Steinert Optic Mold for Glassblowing   4-14-16A - Optic Mold for Glassblowing 
Steinert Industries4"12B = Closed  4-2-12B - Steinert Optic Mold for Glassblowing   4-2-12B - Optic Mold for Glassblowing 
Steinert Industries4"14B = Closed  4-3-14B - Steinert Optic Mold for Glassblowing   4-3-14B - Optic Mold for Glassblowing 
Steinert Industries4"10A = Open  4-4-10A - Steinert Optic Mold for Glassblowing   4-4-10A - Optic Mold for Glassblowing 
Steinert Industries4"6B = Closed  4-5-6B - Steinert Optic Mold for Glassblowing   4-5-6B - Optic Mold for Glassblowing 
Steinert Industries4"20A = Open  4-6-20A - Steinert Optic Mold for Glassblowing   4-6-20A - Optic Mold for Glassblowing 
Steinert Industries4"20B = Closed  4-6-20B - Steinert Optic Mold for Glassblowing   4-6-20B - Optic Mold for Glassblowing 
Steinert Industries4"12A = Open  4-7-12A - Steinert Optic Mold for Glassblowing   4-7-12A - Optic Mold for Glassblowing 
Steinert Industries4"18B = Closed  4-8-18B - Steinert Optic Mold for Glassblowing   4-8-18B - Optic Mold for Glassblowing 
Steinert Industries4"10B = Closed  4-9-10B - Steinert Optic Mold for Glassblowing   4-9-10B - Optic Mold for Glassblowing 
Steinert Industries6"8B = Closed  6-1-8B - Steinert Optic Mold for Glassblowing   6-1-8B - Optic Mold for Glassblowing 
Steinert Industries6"12B = Closed  6-2-12B - Steinert Optic Mold for Glassblowing   6-2-12B - Optic Mold for Glassblowing 
Steinert Industries6"24B = Closed  6-3-24B - Steinert Optic Mold for Glassblowing   6-3-24B - Optic Mold for Glassblowing 
Steinert Industries6"8B = Closed  6-4-8B - Steinert Optic Mold for Glassblowing   6-4-8B - Optic Mold for Glassblowing 
Steinert Industries6"32B = Closed  6-5-32B Steinert Optic Mold for Glassblowing   6-5-32B Optic Mold for Glassblowing 
Steinert Industries6"40A = Open  6-8-40A - Steinert Optic Mold for Glassblowing   6-8-40A - Optic Mold for Glassblowing 
Steinert Industries6"20A = Open  6-9-20A - Steinert Optic Mold for Glassblowing   6-9-20A - Optic Mold for Glassblowing 
Steinert Industries7"14A = Open  7-14A - Steinert Optic Mold for Glassblowing   7-14A - Optic Mold for Glassblowing 
Steinert Industries7"15A = Open  7-15A - Steinert Optic Mold for Glassblowing   7-15A - Optic Mold for Glassblowing 
Steinert Industries9"8B = Closed  9-1-8B - Steinert Optic Mold for Glassblowing   9-1-8B - Optic Mold for Glassblowing 
Steinert Industries9"12A = Open  9-2-12A - Steinert Optic Mold for Glassblowing   9-2-12A - Optic Mold for Glassblowing 
Steinert Industries9"12B = Closed  9-2-12B - Steinert Optic Mold for Glassblowing   9-2-12B - Optic Mold for Glassblowing 
Steinert Industries9"18A = Open  9-3-18A - Steinert Optic Mold for Glassblowing   9-3-18A - Optic Mold for Glassblowing 
Steinert Industries9"18B = Closed  9-3-18B - Steinert Optic Mold for Glassblowing   9-3-18B - Optic Mold for Glassblowing 
Steinert Industries9"24A = Open  9-4-24A - Steinert Optic Mold for Glassblowing   9-4-24A - Optic Mold for Glassblowing 
Steinert Industries9"24B = Closed  9-4-24B - Steinert Optic Mold for Glassblowing   9-4-24B - Optic Mold for Glassblowing 
Steinert Industries9"32A = Open  9-5-32A - Steinert Optic Mold for Glassblowing   9-5-32A - Optic Mold for Glassblowing 
Steinert Industries9"7A = Open  9-7A - Steinert Optic Mold for Glassblowing   9-7A - Optic Mold for Glassblowing 
Steinert Industries9"5A = Open  9-8-5A - Steinert Optic Mold for Glassblowing   9-8-5A - Optic Mold for Glassblowing 
Steinert Industries9"6B = Closed  9-9-6B - Steinert Optic Mold for Glassblowing   9-9-6B - Optic Mold for Glassblowing 
Steinert Industries12"12A = Open  12-12A - Steinert Optic Mold for Glassblowing   12-12A - Optic Mold for Glassblowing 
Steinert Industries12"16A = Open  12-16A - Steinert Optic Mold for Glassblowing   12-16A - Optic Mold for Glassblowing 
Steinert Industries12"24B = Closed  12-24B - Steinert Optic Mold for Glassblowing   12-24B - Optic Mold for Glassblowing 
Steinert Industries12"8B = Closed  12-8B - Steinert Optic Mold for Glassblowing   12-8B - Optic Mold for Glassblowing 
Steinert Industries12"28B = Closed  12.5-1-28B - Steinert Optic Mold for Glassblowing   12.5-1-28B - Optic Mold for Glassblowing 
Steinert Industries18"16A = Open  18-16A - Steinert Optic Mold for Glassblowing   18-16A - Optic Mold for Glassblowing 
Steinert Industries18"8A = Open  18-8A - Steinert Optic Mold for Glassblowing   18-8A - Optic Mold for Glassblowing 
Steinert IndustriesSplit 4"8A = Open  Split 4A - Split Steinert Optic Mold for Glassblowing   Split 4A - Split Optic Mold for Glassblowing 
Steinert IndustriesSplit 6"PineappleA = Open  Split 6A - Split Steinert Optic Mold for Glassblowing   Split 6A - Split Optic Mold for Glassblowing 
Steinert IndustriesSplit 6"PineappleB = Closed  Split 6B - Split Steinert Optic Mold for Glassblowing   Split 6B - Split Optic Mold for Glassblowing 

 


 
At 09:44:46 October 21 2017 displayed this glassblower.info
glassblowing web page at 173.12.39.201 last modified: June 21 2009