Plaster Casts and 3D Scan

As a result of my personal experiences, conferences, congress and technical insights that I could do in these recent years about the traditional casting and digital copy, I think it useful to offer some clarification on this topic. It is appropriate to reveal what really lies behind a technology that, in my opinion, is too often overstated and applied on incorrect areas. I wanted to test by myself the production of digital copies in the sculptural reproduction to finding, between a comparison, the differences with the art of plaster casting. Taking a step back, is necessary to understand well the role that the casts have represented in the past centuries and still today in the historical and artistic context. Within the collections of the eighteenth and nineteenth centuries plaster cast takes on the role of messenger for classical statuary and quickly dedicated itself as a versatile and economical tool in those areas still completely free of art testimony of this kind.
As an object of art is well accompanied alongside ‘original’ works of art then in the next century will take its own absolute value as art object, as a work in itself, although replica of an original of undeniable historical and artistic value and unequaled authenticity. In this way the casts are not only teaching tools, but takes on a double or triple value that goes beyond the physical object. Between the late ‘800 and early ‘900 lots of american museums and many collections of classical and renaissance statuary were made not by marble, but plaster. The plaster cast value is indisputable enough to allow the plant entirely dedicated to galleries also in those locations where there is no shortage of original works.
In Europe, outside of Italy, one of the most important galleries of Italian statuary is the Cast Court of South Kensinghton Museum in London, with its beautiful casts of renaissance sculptures and spectacular architectural plaster refunds maded by the most renowned moldmakers. The same can be said for the Museum of Architecture at the Trocadero in Paris or The Royal Cast Collection in Copenhagen, or even the Royal Academy of San Fernando in Madrid and the Slater Memorial Museum of Norwich in the United States. In the present era it is just significant the new opening of a Cast Gallery inside the renovated Ashmolean Museum in Oxford.

On the left the plaster cast, on the right 3d copy, of the same Egyptian bust of Apis.

That plaster has been masterfully’ translated’ into sculpture by skilled hands, as the result of an ancient and complex technique that is part of the millenary statuary technique. The mold is produced exactly like an original plaster sculpture. Anyway, the ancient sculpture regenerates itself by producing a replica of absolute faithfulness. The mold does not renounce to any artistic values contained inside the original sculpture as the techniques and finest materials. Plaster cast offers itself as a faithful replica in a total sense, and this makes it a respectable importance of art object, precisely because it is originated in order to honor the original through the same craft used by the master sculptor to produced the ‘original work’.
The maker of cast is very often the same technical executor of the original work; the molding technique is the same used to make the plaster model useful to sculpt the final marble.
In this sense no other faithful reproduction of an original work can equalize the plaster cast without renouncing to a ‘full value of work of art’.

In these two images the imperfection and the total lack of details in 3d  copy is very evident. Even the raw strip present on the copy is a grain of the original granite that the 3d scan reads as a gap.

The cast does not takes honors to the work of art that generated it but enhances its importance and magnificence, and spreads the memory. Rather, it is important to recognize the undeniable artistic value that is contained in it as lawful son, especially for antique casts, or which are about to become one.
About these values ​​would be appropriate to preserve that elements that makes a cast as an object of art, ensuring the authenticity of the technique to produce a plaster cast. Establish a manufacturing an origin protocol. Provide guidelines that will be instrument to direct the knowledge.
Over the many modern reproduction systems which tend to confuse between cast and copy it would be desirable to provide conditions that ensure the recognition of the authenticity of a cast made in a workmanlike manner so it would be in accordance with historical collections.
The molding must never move away from traditional techniques that are typical of the sculptural process, and in the same way, will not even deny the materials belonging to this artistic tradition.

The large imperfections on the 3d copy, and even the poor material are embarrassing.

Fidelity of the surfaces, assured by direct replication obtainable with a mold, can not be exceeded. The typical chiaroscuro effect of the plaster is a unique tool in the exercise of academic drawing and technique of the sight-size. The patina of a cast, expertly executed according to the ancient technique, gives it a look and an unsurpassed aesthetic value. Trying to restore the pure white of the fresh plaster, without knowing the techniques that produced that patina, it means damage. Restoration ‘unaware’ leads to a serious loss.
These are the reasons why today we can appreciate the extraordinary quality and beauty of plaster casts within historic gipsoteche, academies and museums. Emotionally we can not do the same in front of a poor quality cast or a bad copy made with 3D technique using modern synthetic materials.

Plaster cast is a Work of Art.

Its manufacture, starting from the molding proces on the original marble to the casting in plaster, presupposes the fundamental technical project by the moldmaker. The profession of the mold make must also be preserved and respected. I have seen improvised techniques of all kinds to make a cast, many so ridicule, which most of the time lead to a disastrous result.

Using a careful analysis of the sculpture to mold, the master moldmaker  ‘studies and understands’ the sculpture exclusively according to all parameters that are the basis of physical laws of his craft. For this reason, the molding is a difficult concept work that requires long experience and knowledge. These evaluations, which are applied always to each sculpture as a new subject to be analyzed,  does not allow to make mistakes. However, only skilled moldmaker will be able to remedy cleverly to any possible errors during his work. The sculpture is ‘views, examined and understood’ not according to its stylistic or artistic character but according to the  material, its plans, volumes, depth, undercuts, and all the elements to be considered in order to fully work ‘in workmanlike’.

A well made cast offers a very fine detailed surface, everything present on the original was reproduced in plaster. The total absence of details and dimensional error make the 3D copy completely useless.

The production of mechanical copies and widespread fever of 3D technologies applied to the sculptures reproduction (often in a forced way), so popular in recent years, is not more than that same effect of speeding that permeates every area of our XXI century culture. The intent of simplifying everything that requires effort and experience.

The rapidity in the art is not an added value.

Carry out more quickly and easily a job that would otherwise require long lead times and the use of highly skilled workers is only a vain shortcut that does not lead to the same destination.
These two methods of reproduction, cast and the digital reproduction, are erroneously associated by claiming that a technology can exclude the other, but it’s a serious mistake. In fact, they are two completely different systems of work, with different features and capabilities that provide very different results, and very far from each other and for this reason are not equivalent. The techniques of molding are very complex, the long time frame of apprenticeship in the workshop or in the sculpture studio, that leads to knowledge of this art profession, is very long. Inside the workshop there is a clear hierarchy and a division of roles and tasks. Only the expert moldmaker will be able to produce an excellent quality cast and especially he will work without causing any damage to the original work.
Mistakenly many think they can get a cast without molding, just buying a 3D printer and a computer. It is not so. The Cast, the best sculpture reproduction system possible, is maded exclusively by a work of molding. All other reproduction results must be defined in absolute Copies. Cast and copy are two very different things.

It ‘easy to understand the convenience offered by a photographic technology reproduction as the 3D scan which does not require artisan experience and a long time learning. At the same time it requires little effort and no physical stress working in a clean environment. But certainly, and this must be clear to everyone, the result will not be an artistic work. The model came out of the printer will not be a faithful cast of the original, but only a rough copy. Not faithfully return every minutest detail of the surface and volume of the original as the plaster cast does. It will not be produced with a noble material such as plaster and will never own all the objective artistic values that instead the cast includes. Technically, in the 3D reproduction some errors are added during the operating phases:
The set of points (which forms a dense network) that represents the digital work surface does not correspond to the fidelity and accuracy of the same cast that instead, by direct contact, returns perfectly an homogeneous surface.
During the acquisition phases of the digital model (scan) many areas of the original sculpture (undercuts) are not reachable by the ray (laser and structured light) and must be completed ‘arbitrarily’ from the hand of an operator in the editing stage through the ‘use’ of a joystick ….

To provide a comparison, I remember that in past centuries the skilled moldmakers used to left on the cast surfaces all the signs produced by the pieces of the mold. Allowing, in this way, that no ‘other hand’ had altered the fidelity of the plaster surfaces compared to those of the original marble.

The Acquisition of digital model is get proceeding by fragments or small areas that have to be ‘stitched up’ in post production by the operator using a software generating additional volumetric and compositional errors.
Some different color of the marble or bronze interferes with scanning systems producing erroneous readings of the real model.
In Phase of creation of the digital model, the printer machine (for addition) or the milling machine (by subtraction)  produces lot of signs and systematic pattern on the entire surface of the copy. These signs must be removed manually compromising, in practice, all the logical of exact replica of an original.
All this set of errors and crude imperfections do not occur by the cast where just apply skilful way in the molding technique and the materials suitable for obtaining an excellent replica reproducing every detail with perfection.

Plaster Cast made by Andrea Felice. 3D Copy by a specialized company which I prefer not to write the name.

All photos are by Andrea Felice, 2016.