Near infrared spectra

Mark Clarke <markey [at] gn__apc__org> writes

>Does anyone have (or have references to) Near IR spectra of
>pigments?
>
>The region I am interested in is 700-900 nanometers, and the
>materials I am most urgently interested in are Lapis Lazuli, Indigo,
>Azurite and Smalt.

My English is not enough to write.

    **** Moderator's comments: The following is a translation.
    Apologies for any inaccuracy

You could find responses to the questions in one of the following,
notably in the first one:


    Walmsley, Elizabeth, Colin Fletcher, and John Delaney.
    Evaluation of system performance of near-infrared imaging
    devices.
    Studies in conservation
    Volume 37, Number 2, 1992 pp. 120-131

    Walmsley, Elizabeth, Catherine Metzger, Colin Fletcher, and
    John K. Delaney.
    Evaluation of platinum silicide cameras for use in infrared
    reflectography.
    Preprints. ICOM Committee for Conservation tenth triennial
    meeting, Washington, DC, 22-27 August 1993

    Delaney, John K., Catherine Metzgar, Elizabeth Walmsley and
    Colin Fletcher.
    Examination of the visibility of underdrawing lines as a
    function of wavelength.
    Preprints. ICOM Committee for Conservation tenth triennial
    meeting, Washington, DC, 22-27 August 1993: preprints

Personally, I use a CCD Camera (700-1100 nm) and supplement it with
a Hamamatsu vidicon (1800-2200 nm). In practice, they complement
each other and sometimes they appear to contradict the theory
expressed in these articles. I mean, I observed in doing "homework"
with either one or the other, these supposed elements ar not visible
in the respective wavelengths of each camera. But all that enhances
an empiric course not yet formalized.

Gerard de Wallens
Laboratoire de Recherche et d'Analyse Scientifiques de Tableaux.
52 Elysee II
78170 La Celle Saint-Cloud
+33 1 39 69 60 80
Fax: +33 1 39 69 60 86



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