Find out why the "Flowers in Blue Vase" by Van Gogh darkened

[Кирилл Сызранский]

Asters in a painting by Vincent Van Gogh's "Flowers in Blue Vase" gradually turned from bright yellow to brown due to chemical reaction between the "lemon" pigment, cadmium sulfide, and a protective lacquer, according to the article published in the journal Analytical Chemistry.

Vincent Van Gogh painting "Flowers in a Blue Vase" in 1887, in the twilight of the Paris period of life of this great artist. In this painting depicted a bright yellow daisies and white anemones in a vase placed on the table. After the death of van Gogh, this picture was covered with varnish to enhance the conservation and bought in the early 20th century, Kröller-Müller Museum in the Netherlands Otterlo, RIA "Novosti".

Group of chemists led by Kuhn Janssens of the University of Antwerp (Belgium) has turned its attention to the picture after restorers discovered an unusual attack on some parts still life.

As the scientists explain, the yellow pigment - cadmium sulfide - gradually loses its brightness in contact with air. This is because the oxygen molecules oxidize sulfur and make the connection to sulfate, sulfate (SO4). Cadmium sulfate forms a white translucent film on the surface of the paint, making it fades and loses its usual brightness.

In the case of "Flowers in Blue Vase" raid was unusual - it was not the light, and dark, and its microstructure was not similar to cadmium sulfate crystals. Puzzled museum staff sent a small piece of paint from the painting to the lab and asked Janssens chemists determine the nature and cause of the formation of plaque.

Researchers enlightened paint samples using X-ray spectroscopy at the European synchrotron center in Grenoble and a German laboratory DESY and compared them to the "normal" bloom of cadmium sulfate.

"It turned out that the sulfate anions found the right partner for the reaction in the ions lead paint and therefore on the border between the paint and varnish formed gray and maloprozrachnye anglesite crystals - lead sulfate. His source, apparently, was the substance drier, which was added to coat with cover picture, "- said one of the participants in the work of German Gerald Falkenberg synchrotron center DESY.

According to scientists, the effect is compounded by the fact that cadmium ions devoid of sulfur react with other components of the paint and turned into cadmium oxalate (CdC2O4) - a combination of oxygen, cadmium and carbon. A combination of lead salts and cadmium oksolata and is the raid, which turned bright yellow daisies in a painting by Van Gogh in a mixture of orange and dark brown smears.

"Many of the paintings that Vincent wrote during the Paris period, were covered with lacquer and improper removal of this cover is one of the most difficult tasks faced by the restorers of Van Gogh in all countries of the world. Information provided by you Janssens and his colleagues, vital to making tough decisions that we have to do at times when such a complex cleaning of paintings "- added Restorer Ella Hendriks of the Van Gogh Museum in Amsterdam (Netherlands).

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[NATA NOVA]

Koroche, ladies and gentlemen artists no further-driers (ie everything has to dry naturally).
I understood correctly? Lucky (and paint pigments) only natural (old) with no bullshit ..

[Seriy]

NATA NOVA, and Van Gogh was not old?
:-) Cadmium pigments are the most reliable.
But would synthetics and under the acrylic paint and she sulfur and oxygen?

[NATA NOVA]

Сообщение от Seriy

But would synthetics and under the acrylic paint and she sulfur and oxygen?

other (popular) with the words: ...
...
Cover ... what?

[Seriy]

NATA NOVA, styrene-acrylic lacquer.

[NATA NOVA]

Сообщение от Seriy

NATA NOVA, styrene-acrylic lacquer.

We look for ...
(As well, there is a clever chemist Iksigon!)

Added after 2 minutes

Сообщение от Cyril Syzran ; 2259491"

"Many of the paintings that Vincent wrote during the Paris period , were covered with varnish wrong

Сообщение от Cyril Syzran ; 2259491"

" It turned out that the sulfate anions found the right partner for the reaction of lead ions in lacquer coating

 Well, a word that the varnish was wrong .. Now do not go to sleep ...

[Seriy]

NATA NOVA, probably, lead (lead-salt) was added to a lacquer-drier to speed drying.
Now these varnishes not sleep well.

[NATA NOVA]

Сообщение от Seriy

probably lead (lead-salt) was added to a lacquer-drier to speed drying.
Now these varnishes not sleep well.

__________________

is now drier bottle recycle?
(How to use without damage to the painting and health?)

bought (just in case), but did not open <- ~ 3 ~ ->

[Seriy]

NATA NOVA, to give another artist who uses it.
In driers for painting-cobalt.

[NATA NOVA]

Сообщение от Seriy

In-driers for painting cobalt.

I have read a dozen times but did not understand ...