Nobili's Art: an
Example of Generative Art of 1826
Pietro Pedeferri
Dipartimento di Chimica Fisica
Applicata
Politecnico di Milano
Abstract.
In
1826 Leopoldo Nobili obtained colors of interference on metallic surfaces
through electrochemical oxidation and studied them and technique to obtain them
not only for scientific reasons but also for «the advantages that these colors
and new technique of coloring metals may lend to the arts». Nobili's work can
be considered an is example of generative art.
1.
Nobili's Art
At
the beginning of the last century, a number of eminent Italian scholars of
electrochemistry attempted to contribute new technologies to the decorative
arts. As early as 1800, just months after the invention of the battery, one of
Volta's colleague in Pavia University, Brugnatelli, carried out experiments on
the electrodeposition of metals. In so doing, he enabled the goldsmiths of that
city to be the first to use the new technique. Leopoldo Nobili invented the
'metallocromia' in Reggio Emilia in 1826. A short time later (1840) in Novara,
Marianini, pioneer in the field of galvanoplastics, perfected a method for
obtaining bas-reliefs in copper. The same year in Venice, Zantedeschi became
one of the earliest cultivators of electrotyping and published a paper on this
technique. In 1844 in Modena, the founder of colloidal chemistry, Selmi,
published 'Manual on the Art of Gilding and Silverplating with Electrochemical
Methods'. The development of this field was such that Grimelli, in 1844, had his
"A Scientific and Artistic History of the Origins of Electrometallurgy in
Italy" published.
Among
all the early developers of the field, Leopoldo Nobili stood first and
foremost. A scientist of the highest
rank, he obtained colors of interference on metallic surfaces through
electrochemical oxidation and devoted himself to study them not only for
scientific reasons but also for «the advantages that this new technique of
coloring metals may lend to the arts».
The
results of his studies, initiated in 1826, were published in 1830, in a very
important paper entitled, On Colors in
General and in Particular on the New Chromatic Scale Produced by the
'Metallocromia' as Applied in the
Sciences and Arts [1].
His
tombstone in Santa Croce - not far from those of Galileo and Michelangelo -
reveals these two aspects of his personality in stating that he was «promotor
of the physical sciences and inventor and maestro of the art of
'metallocromia'».
Nobili's
art could perhaps be defined as "generative". Nobili obtains it
starting from an idea and an instrument. The idea is to utilize the forms that
the electrical currents («il torrente elettrico») take in an electrolytic
conductor. The instrument is an apparatus in which the operative parameters can
be varied - the «apparatus with needles» («l'apparecchio a punte») [2]. In this
way he can obtain a multitude of forms, all different from one another, yet all
obeying the same laws.
Nobili's
generative art is obviously of the analogic type since it exploits a natural
phenomenon to create forms, while normally today generative art is numerical
because it resorts to the virtual spaces and the behavioral codes that
computers and software put at our disposal.
2. The idea
Let's
listen to Nobili [1]:
"In
1826 I discovered a new class of phenomena that I called "electrochemical
appearances". One of the principal experiments was the following: a
platinum needle is placed above a plate of the same metal so that its distance
from the latter is about half a line. The needle presses down vertically on the
plate, the underside of which rests on the bottom of a glass or porcelain vase.
A solution of lead acetate is then poured into this container in such a way
that it not only covers the platinum sheet but also two or three lines of the
tip. Finally, the tip is connected to the negative pole of a battery, and the
sheet to its positive pole. At the exact moment the circuit is completed, one
can see the formation of a series of
colored rings on the sheet, directly under the tip; these rings are similar to
those that appear in the middle of Newton's lenses. This phenomenon, which
would surprise any observer the first time, led me to discover many others».
We
shall interrupt our story to give the reader some additional information. When
Nobili connected the plate and the tip to their receptive positive and negative
battery clamps, current circulated between the plate, which acted as anode, and
the tip, which acted as cathode, through the lead acetate solution. This
current produced a thin layer of lead dioxide and gave rise to colors of
interference which differed according to the layer's thickness. If the geometry
of the system used, that is, of the anode, cathode and cell, is such that the
current is uniformly distributed over the anodic surface, a film of uniform
color and thickness are obtained. If the current is not uniform, the thickness
differs in every point of the surface and varies with the local current
density. Consequently, the colors also vary, to produce on the plate a chromatic
map of thickness of the deposited lead dioxide and thus also of current
density: the 'electrochemical appearances' as they have been called.
Nobili
continues:
«I
will pass over my first attempts and examine for a moment the products that I
obtained in 1828 and presented to the Institute of France in November of that
year. These consisted of many colored plates whose beautiful shades, precise
contours and soft nuances attracted the attention of the entire illustrious
assembly. This art had now come into its own and could take its place with the
others. A name was required to distinguish it and 'metallocromia' was chosen on
the advice of the learned men of the Institute. Following that period, I
greatly perfected my methods, and now the works that at first had seemed
wonderful cut a very poor figure indeed when viewed alongside those I am
presently making».
2. The apparatus
Nobili
had observed, even in his first experiments, that if a single needle is used,
one obtains «various concentric rainbows formed one within another, which
extend rapidly outwards, like waves». If multiple needles are used, «an equal
number of concentric circles are formed; these do not cross each other as they
dilate but once touching extend outwards together so that they form a single
outline». Finally, if besides number, other variations are made in the form,
spacing and arrangement of the points or their distance from the plate, or if
metallic or insulating shields are placed in the cell, then «the effect becomes
even more vague and variegated». He therefore constructed an «apparatus with
needles» capable of controlling the principal parameters which determine the
distribution of current and thus the form of the appearances.
Nobili
later built a second apparatus, known as the «uniform color apparatus»
(«apparecchio per colori uniformi») [3]. With it, Nobili produced forty-four
different colors on an equal number of plates. He organized them with
progressive numbers and with names so as to form what he called «a chromatic
scale for use in the sciences and arts». This 'scale' became not only the
palette of his 'metallocromia', but also the chromatic spectrum to measure the
chemical effects of circulation of current and «the harpsichord of colors» with
which to study their harmonies. It is clear, then, that he recommended it «to
the studies of physicists as well as artists». Nobili tough that «science never
fulfills its own purpose as well as when it aims to be useful by lending a hand
to the arts».
Nobili
knew that his research in the field of 'metallocromia' was important on the
scientific front. Namely, although he carried it out with limited means in just
a few years, the results he obtained should have assured him an outstanding
place in the history of electrochemistry. Nobili also hoped that his research
might have given to the world of art new methods and new technologies. Actually
few artists used the 'appearances' or the 'apparatus with needles', i. e. the
hardware and software he prepared for them. Numerous scientists did, however.
Among these were, first of all, electrochemists - like Marianini, Becquerel
(senior), De La Rive and Dubois-Raymond - and. mathematicians - such as Rieman,
Mach and Volterra - in their search for an analytical solution to the equations
that describe the appearences and the laws of the phenomenon that produces
them. In the instruments, the rules and the explanations that Nobili prepared
for artists, these scientists found stuff for meditation and tools for
exploring the distribution of currents in galvanic systems and for finding
analytical solutions - I would say chromatic solutions - to the equations that
regulate this phenomenon.
In
the last thirty years, starting from Nobili's ideas and utilizing the special
properties of titanium, I have produced new types of appearances [4].
Bibliografia
1. L. Nobili: Sui colori in generale ed in particolare
sopra una nuova scala cromatica dedotta dalla metallocromia ad uso delle
scienze e delle arti, Antologia, 39, 117, 1830 e su Bibl. Univ. 15, 337,
1830; e 16, 35, 1830
2. L. Nobili, Apparecchio a punte, in Memorie ed
osservazioni edite ed inedite, Parte seconda, 15, D. Passigli, Firenze, 1834
3. L. Nobili, Apparecchio per tinte uniformi, in
Memorie ed osservazioni edite ed inedite, Parte seconda, 17, David Passigli, Firenze,
1834
4. P. Pedeferri, Titaniocromia (e altre cose),
Interlinea, Novara, 1999