Re: secrets of the masters$$$ pt 1
In Reply to: secrets of the masters$$$ pt 1 posted by part 1 on 09/11/00 at 8:38 PM:

Thank you for the generous complements. My knowledge of chemistry is not nearly as developed as Rob's, however. I generally rely on the expertise of those more qualified than myself. The link you provide is a very good source of information. It's basically a very watered down version of Ernst van de Wetering's book.

I'm assuming that your conclusion about Rembrandt's medium is based on the reference to the 1988/1989 study by the chemist from the London National Gallery. Raymond White concluded that "Rembrandt had a preponderance to linseed oil as a binder of his paints...One may say that in general a sound medium -linseed oil- has been employed in an uncomplicated way, that is, without detectable additions of other materials."


The Rembrandt Research Project and the Dutch chemical corporation DSM took this idea as a starting point for new research that yielded very different results and conclusions. Here are some excerpts:

"There are reasons to believe that this shift in point of view does not eliminate the problem. What to think of Hoogstraten's [Rembrandt pupil] enigmatic remark on Jan Lievens being 'expert in seeking wonders in smeared pigments varnishes and oils', and the fact that Rembrandt, once Lievens' companion, may well have been Hoogstraten's spokesman on the issue. Moreover, Rembrandt's paint indeed seems to have a variety of properties, or at least shows a range of effects which seem impossible to achieve with paint of a uniform composition of pigment and oil alone....Paint behaving in so many different ways seems to be more than just pigment and oil. It has a variety of potential properties of a completely different rheological nature (rheology being the study of the flow of properties of plastic materials...."

"..the analysis of the paint with lead white seemed to be the most important one for understanding Rembrandt's style of painting, as this shows the greatest variation in surface texture and has also been mixed with other pigments in the light, usually pastose parts of the painting."

"this research in collobaration with the specialists from DSM and other laboratories, identified more organic materials in these paint samples than the National Gallery's Scientific Department had found in its samples."

"When some of sample material taken from the white impasto of the Jewish Bride was analysed by Pyrolysis Mass Spectrometry in the FOM Institute of Atomic and Molecular Physics (AMOLF) in Amsterdam, the outcome was nearly identical with Raymond White's results: only cold-pressed, unheated oil could be found.
However, when part of the same sample was analysed by High Performance Liquid Chromatography (HPLC) at DSM reasearch, proteins suggesting egg were found. This result was not just an incident, as may happen in chemical analysis: it was confirmed several times when lead paint samples of other paintings by Rembrandt, like the Claudius Civilis were analysed by the same method."

"The paste that is the result of the addition of water and egg to the paint has rheological properties that theoretically differ from a paint based on only oil and pigment. The emulsion has more 'body', and the movement of the brush becomes easier, while the brushstroke completely preserves its shape after the brush has been lifted. The variation of textural effects to be obtained with such paint is greater that with the oil/pigment mixture."

".. the red glazes of the skirt of the woman in the jewish bride yielded a surprise as well.. Magnification of a paint cross-section of the red glaze...revealed the presence of round and oval holes in the surface of the paint. With another technique to identify organic components, Fourier Transform Infrared Spectrometry...an unexpected addition to the red paint was found. The discovery of this component, specific for sugar or gum, confirmed that the red glaze in the Jewish Bride is an emulsion as well, this time of oil with another watery substance than egg; the cavities in the paint must be interpreted as the traces of water drops emulgated in the oil....
...Karen Groen has suggested here that an emulsion was chosen here because of the considerable thickness of the glaze obtained in this way."

"The idea..that each passage in a painting, or even each stage in the buildup of a passage, may have required its own palette-could well imply that the use of a binding medium may have varied accordingly. The results of the research discussed here- for only two pigments up to this point- seem to confirm the hypothesis.
That hypothesis was supported further when the paint containing the glass or smalt particles..was found to contain components that indicate the presence of animal glue in the paint."

"The nature of the unique impasto in the sleeve of the man in the Jewish Bride may require another approach. In this extremely heavy impasto no toolmarks are discernable...It has been suggested that this effect in the Jewish Bride was obtained by applying fragments of the nearly dry skin of discarded white pain to the surface of the sleeve. Testing this hypothesis may require a a specific kind of morphological study of that particular paint surface.
Another phenomenon found on a much larger scale, thixotropy, deserves attention as well. Thixotropy is a rheological phenomenon that can be described as a reversible change from a set, gel-like condition of a plastic material to a more or less fluid condition under the influence of some mechanical force of, for instance, a brush...the appearance of the surfaces of Rembrandt's paintings has led rheologists, confronted with these phenomena, to believe that Rembrandt used thixotrophy as well...One could therefore ask the question of whether some of the variations in Rembrandt's paint consistency and surface texture might be caused by the conscious manipulation of the degree of thixotrophy.
Such insights cannot be obtained by paint analyses with methods such as these mentioned above. Nor can they be 'read' with any objectivity form the surface of Rembrandt's paintings...It will be necessary to reconstruct paint according to the 'recipes' which are slowly emerging from the analysis of paint samlples"


Excerpts from Rembrandt: The Painter at Work
by Ernst van de Wetering

Hope that helps.


: You are very welcome Will, a.k.a. Rob Howard, aka, most other names on
: this board. The interesting thing is that your writing style is so similar to Rob
: Howard's, and apparent chemistry linguistics knowldedge ,maybe you are his twin.
: It is this bogus posting that keeps me rolling laughing, not your ignorance. Then maybe you are familiar with the fact that Maroger
: medium contains resin/varnish? if you read Ernst van de Wetering's book you mentioned, you would see that Rembrandt
: did not use resin/varnish in a medium. . For a site that will really
: keep you rolling on the floor laughing try this, Mr. Sarcastic Rob Howard,

: http://japan.park.org/Netherlands/pavilions/culture/rembrandt/

  Follow Ups:

Re: secrets of the masters$$$ pt 1 rob howard   Posted at: 09/13/00 (2)
Re: secrets of the masters$$$ pt 1 James Morton   Posted at: 09/14/00 (1)
Re: secrets of the masters$$$ pt 1 rob howard   Posted at: 09/14/00 (0)
Re: secrets of the masters$$$ pt 1 Ed   Posted at: 09/12/00 (11)
Re: secrets of the masters$$$ pt 1 James Morton   Posted at: 09/14/00 (4)
Re: secrets of the masters$$$ pt 1 Stump   Posted at: 09/14/00 (3)
Re: secrets of the masters$$$ pt 1 James Morton   Posted at: 09/14/00 (2)
Re: secrets of the masters$$$ pt 1 rob howard   Posted at: 09/18/00 (0)
Re: secrets of the masters$$$ pt 1 rob howard   Posted at: 09/18/00 (0)
Re: secrets of the masters$$$ pt 1 Will   Posted at: 09/13/00 (0)
Re: secrets of the masters$$$ pt 1 rob howard   Posted at: 09/13/00 (4)
Re: secrets of the masters$$$ pt 1 Ed   Posted at: 09/13/00 (3)
Re: secrets of the masters$$$ pt 1 Ed   Posted at: 09/13/00 (2)
Re: secrets of the masters$$$ pt 1 rob howard   Posted at: 09/14/00 (0)
Re: secrets of the masters$$$ pt 1 rob howard   Posted at: 09/14/00 (0)
 
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