Art & Degas’ Obsession

Delaunay triangulation of a moth, the third stage in 'Tracing the Hollow' — a digital triptych exploring presence and absence, inspired by Degas' decades-long reworking of Dancers Practising by Edgar Degas exihbited at Glyptoteket in 2025. By Danish Artist Kasper Bergholt.

The oldest light we can observe, the cosmic microwave background radiation, is nearly 14 billion years old.

D defining trait of light is that it cannot be owned, at least not yet. In a sense, trees can archive light temporarily through photosynthesis and transform it into chemical energy.

A line can be said to span two ends of a spectrum of light: sunlight, the natural and warm light that is about 8 minutes and 19 seconds old when it reaches Earth, and light from distant stars that has traveled for thousands of years, on the one hand, to light from artificial sources or reflected light, on the other hand, which reaches us in nanoseconds.

So we see an axis that represents the distance light travels, and another axis that covers the range from natural to artificial light.

The word “artificial” is interesting in this context because, the word presents itself to us, much like light. It originates from the Latin artificialis, which in turn traces back, just as light moves outward, to artificium.

This leads us back to the root ars (art, skill) combined with facere (to make, to bring forth).

Lead white is produced by exposing lead plates to vinegar fumes and carbon dioxide. This process forms a white crust on the lead, which is then scraped off and used as pigment. Around 1840, zinc white was invented, and titanium white followed in 1919.

Unlike the ochre, hematite, manganese oxide, and charcoal of ancient cave paintings, these pigments are artificial and human-made, recalling Derrida’s concept of the pharmakon.

Producing pigments transforms natural substances into something artificial. They are toxic, potentially lethal, yet they also represent a technology that enables new forms of art.

Also see: 72 Poems for 72 Solar Eclipses

Object #1 – Degas Fragment

Simulated glass plate photography of a tiny pigment fragment from Dancers in the Foyer by French impressionist painter Edgar Degas (1834-1917). CCD-based photo taken on July 20th using a CCD-based camera – a photo of a photo of a fragment of a pigment, removed from Dancers in the Foyer.
A low-resolution, CCD-based image which simulates glass plate photography to capture a minute pigment fragment removed from Dancers Practicing in the Foyer, a work by French Impressionist Edgar Degas (1834–1917).
The original painting is currently on view at Glyptoteket in Copenhagen as part of the exhibition Degas’ Obsession, running through November 29 [2025].

Object #2 – White Layer

"Mythologie blanche - la métaphysique effacée en elle-même, la scène fabuleuse qui l’a produite et qui reste néanmoins active, remuante, inscrite à l’encre blanche, dessin invisible et recouvert dans le palimpseste. Ce dialogue dissymétrique - faux, ne mérite pas d’être placé en exergue par la sele rasion qu'il frappe ; et parce que frappant la rasion non moons que l'imagination, il grave note problème en effigie théâtrale Il a d'autres titres ..." (Quoted from the 'Exerque' part of 'La mythologie blanche, original French edition of 'Poétique', 1971, pages 4 & 5 by Jacques Derrida).
“Mythologie blanche – la métaphysique effacée en elle-même, la scène fabuleuse qui l’a produite et qui reste néanmoins active, remuante, inscrite à l’encre blanche, dessin invisible et recouvert dans le palimpseste. Ce dialogue dissymétrique – faux, ne mérite pas d’être placé en exergue par la seule raison qu’il frappe ; et parce que frappant la raison non moins que l’imagination, il grave notre problème en effigie théâtrale Il a d’autres titres …” (Quoted from the ‘exergue’ part of ‘La mythologie blanche, original French edition of ‘Poétique’, 1971, pages 4 & 5 by Jacques Derrida). Subsequently, Object #2 was used as the background image for the Moons, Castles, Trees exhibition.

“White Layer” consists of a white-toned digital canvas composed of fourteen digital layers, each created from tiny fragments of a CCD-based photograph of the paint pigment extracted from Degas’ Dancers Practicing in the Foyer.

“People can often be heard exclaiming, “Look at that natural light,” even while standing in artificially lit museum rooms.

Object #1 reveals a structure resembling geological strata. It is a very small fragment taken from the painting by Edgar Degas painted around 1882, and photographed through a Zeiss microscope (a process that uses artificial light) using a method called X-ray fluorescence (etymologically derived from the mineral ‘fluorspar’) spectroscopy (XRF).

So we have the literal (the title of the painting, the painter’s name), the mineral (the pigments), and the artificial (the creation of a representation of a scene that never existed at a single moment in time, but was instead the result of years of reworking.

The fragment was then photographed again with a camera using a CCD sensor, which offered a new perspective on the light. The combination of the microscope, camera lens, and CCD sensor created an image of something that Degas himself never saw as a visible object; yet, through this process, it was transformed into an object in its own right.

The artificial light that Degas worked under, whether from gas lamps or early electric sources, illuminated pigments that were themselves toxic due to their lead content.

More recent research has shown that it is possible to stop light by deforming the structure of two-dimensional photonic crystals. This could pave the way for quantum computers and groundbreaking methods of data storage.

The second object is entirely digital and inorganic, offered as both a reference point and a counterpart to the tiny paint flake from Degas’ Dancers Practicing in the Foyer.

The Getty Conservation Institute has described the method in connection with a similar analysis being done on the ‘The Milliners’ after an X-ray had shown several phases of rework, including the erasing and adding of persons:

“Because XRF is an X-ray technique, information is gathered simultaneously from all the paint layers; therefore, elements may be detected from a ground layer, together with those from overlying paint layers. If the painting has a complicated layer structure (as the X-radiograph indicates is likely the case for The Milliners), it is usually necessary to remove small samples for additional analysis in order to more fully understand the painting’s construction.

Samples taken from paintings are barely visible to the human eye (their size is less than 1 mm, typically on the order of only several hundred microns).

— The Working Methods of Degas: The Milliners, The Getty Conservation Institute, 2008

Based on similar technical analyses, researchers could establish that Degas started working on ‘Dancers Practicing in the Foyer’ a lot earlier than previously thought, and that he worked on it, adding and removing layers and motifs, for close to 30 years, a process which might, in psychoanalytic terms, be described as hypercathexis.

The painting contains up to 14 layers of paint.

Also see: Objects for an Ideal Home

Hough Lines Transformormation of the Moth