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  1. #1
    Mustafa Umut Sarac's Avatar
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    Leonardo Da Vinci

    Here is a report on research for Da Vinci. It says he had been used half a human hair thickness glaze and paint layers , sometimes 30 layers , at his paintings.
    Here is the question , is it possible to create a emulsion for portraits with exposable glaze dye layers in it ?

    Here is the news report from aol :

    It's one of the things about the "Mona Lisa" that's long baffled art historians and viewers alike -- how Leonardo da Vinci used rudimentary pigments in the year 1503 to create such subtle shadows and light on the mysterious woman's face.

    And it's taken scientists more than 400 years to come up with technology to figure out how.

    Now French researchers are using X-ray fluorescence spectroscopy, a noninvasive technique, to isolate and study each ultra-thin layer of paint and glaze da Vinci used on the "Mona Lisa" and six other paintings at Paris' Louvre Museum. Scientists from the Center for Research and Restoration of the Museums of France brought their high-tech machine into the museum while it was closed, and zeroed in on faces depicted in the paintings, which have a dreamy, hazy quality about them.

    ESRF, V.A Sol / AP
    Specialists from the Center for Research and Restoration of the Museums of France found that Leonardo da Vinci painted up to 30 layers of paint on his works to meet his standards of subtlety.
    Da Vinci used a renaissance painting technique called "sfumato," mixing thin layers of pigment, glaze and oil intricately to yield the appearance of lifelike shadows and light. The technique is well known and has been employed by other artists over the years. But only now have scientists been able to analyze just how intricate da Vinci's layers are.

    They believe da Vinci used up to 30 layers of paint on his works. But altogether they only add up to a thickness of less than 40 micrometers of paint -- about half the width of a human hair. Details were reported Friday by several news agencies.

    The scientists were able to beam X-ray technology at the paintings without even removing them from the museum wall.

    "This will help us to understand how da Vinci made his materials... the amount of oil that was mixed with pigments, the nature of the organic materials," senior scientist Philippe Walter told CNN. "It will help art historians."

    The new analysis also shows that da Vinci was constantly trying out new mixes and methods. In the "Mona Lisa," he mixed manganese oxide with his paints, but in others he used copper, Walter also told The Associated Press. Da Vinci used glazes in some paintings but omitted them altogether in others, he added.

    "We realize when glazed over, for instance on the 'Mona Lisa,' that he managed to place layers as thin as one or two micrometers, which means one or two thousandths of a millimeter," Walter told EuroNews. "By super-imposing the layers very progressively and slowly, he managed to create the effect he was seeking."

    The research was published in Wednesday's issue of a chemistry journal, Angewandte Chemie International Edition. In addition to the 'Mona Lisa,' scientists also studied Leonardo's Virgin of the Rocks, Saint John the Baptist, Annunciation, Bacchus, Belle Ferronniere, Saint Anne and the Virgin and the Child, Agence France-Presse reported.

    While this research solves one mystery about the "Mona Lisa," others persist, like who the enigmatic woman is, and why she holds that subtle half-smile. Many experts believe she's Lisa Gherardini, the wife of a prominent merchant from Florence. Da Vinci is believed to have started the painting in 1503, and worked on it for four years.


    Best ,

    Mustafa Umut Sarac

    Istanbul

  2. #2

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    Quote Originally Posted by Mustafa Umut Sarac View Post
    =
    ...
    "We realize when glazed over, for instance on the 'Mona Lisa,' that he managed to place layers as thin as one or two micrometers, which means one or two thousandths of a millimeter," Walter told EuroNews. "By super-imposing the layers very progressively and slowly, he managed to create the effect he was seeking."
    ...
    l
    I don't know the answer to your question (or even really understand what your question is), but did want to comment on the portion quoted above.

    It surprises me that they would say that Leonardo "managed to place layers as thin as one or two micrometers". Surely if that is the current thickness (as is indicated in the story), wouldn't they have been significantly thicker 500 years ago?

  3. #3
    Christopher Walrath's Avatar
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    A friend of mine had this technique done to approximate pigmentation in recreation of earlier appearance on a project. This is an awesome report. Thank you for sharing it with us. Very interesting.
    Thank you.
    CWalrath
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    "Wubba, wubba, wubba. Bing, bang, bong. Yuck, yuck, yuck and a fiddle-dee-dee." - The Yeti

  4. #4
    Mustafa Umut Sarac's Avatar
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    Hi Christopher , Its a pleasure to share these with excellent people of APUG.

    I had been posted a multispectral virtual restorated Mona Lisa picture and colors were like Velvia mostly.

    I read Magnesium Oxide pigment plus linseed oil glazes used at Mona Lisa. There are two Anatolian connections. First magnesium word comes from old South West Anatolian city Magnesia , second Mona Lisas husband was an silk merchant and Chinese Silk Road was under control of Turks at the west end.

    Well , I researched some little bit about Magnesium Oxide and I learned it is main reference white color for spectrophotometers.

    And other famous faces like Maiden on the Rocks , was glazed with copper pigment.
    Copper was a Egyptian recipe also and blue. Some of the Michelangelo frescoes bright green color comes from natural copper mineral Malachite.

    I wanted to put Wiley , Revealing the sfumato Technique of Leonardo da Vinci by X-Ray Fluorescence Spectroscopy , paper on to forum but cost is 35 dollars.

    I will ask my sister , She is an doctorate student at France to find me this paper free. Than We will dscuss more.

    Best ,

    Mustafa Umut Sarac

    Istanbul

  5. #5

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    What "Wednesday's issue of a chemistry journal, Angewandte Chemie International Edition"?

    If you get that article, and put it up here, Wiley will want a lot more than those $35 from you.

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    Quote Originally Posted by Mark Crabtree View Post
    It surprises me that they would say that Leonardo "managed to place layers as thin as one or two micrometers". Surely if that is the current thickness (as is indicated in the story), wouldn't they have been significantly thicker 500 years ago?
    Why should they have been significantly thicker 500 years ago? My understanding is that, when oil paint is applied to a canvas and starts to cure, it expands for a while, and then contracts, before eventually drying and becoming pretty-much inert. Depending on the proportion of oil in the paint, and possibly the presence of other substances, the curing process can take anything from a few weeks to several months for a single layer of glaze or application of impasto. I've never come across anything that suggests that layers of glaze will continue to shrink over centuries.

    The amount of expansion and contraction, at least with impasto, is tiny - imperceptible in the impasto stuff that I've done, so I'd assume the change in bulk/thickness is in the order of a few percent. My impasto brushstrokes, several years later, look exactly like they did when I applied the paint, so my feeling is that after the paint has expanded and shrunk, it returns to something very close to its original size.

  7. #7

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    One assumption that shouldn't be is that it is something special to smear paint out so thin.
    So don't build on that.



 

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