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Subject: Retouching

Retouching

From: Mark D. Gottsegen <mdgottsegen>
Date: Saturday, May 6, 2006
Menon V. Sreekumar <vskmenon [at] hotmail__com> writes

>I am working on a contemporary painting in acrylic medium. I would
>be grateful if someone can advise me on mediums used for
>inpainting/retouching the acrylic paintings. I am mainly concerned
>about reversibility parameters of retouching media.

Golden Artist Colors, <goldenpaints.com>, has two paints for this
purpose.  Here are excerpts from their website regarding the paints:

    <URL:http://www.goldenpaints.com/technicaldata/msapaint.php>

   "Golden MSA Colors are produced with a Mineral Spirit-borne
    Acrylic resin system. They dry quickly to form very durable
    films with excellent chemical resistance to acids/alkalis,
    water, and ultraviolet rays. All of the pigments in GOLDEN
    Acrylics are chosen for the greatest clarity & permanency within
    each chemical class.

    MSA Colors remain soluble in mineral spirits, making them ideal
    for easy removal without disturbing the layers of paint
    underneath. For this reason, they are beneficial in art
    conservation for inpainting techniques.

    There are several ways that these paints can be applied.

        *   Direct Application
            Apply directly from the container or palette while wet.

        *   Indirect Application
            Apply paints to palette, allow to dry, and re-solublize
            with a brush dipped in mineral spirits.

        *   Spray Application
            Blend the paints with the MSA Varnish (10% increments to
            reach desired intensity) until smooth, then blend the
            mix equally with mineral spirits. Employ airbrushes that
            do not have "O-rings" that react with solvents."

--------

and

    <URL:http://www.goldenpaints.com/technicaldata/pvacolor.php>

    PVA Conservation Paints

   "Golden PVA Conservation Paints are made from PolyVinyl Acetate
    (PVA) resins, specifically a 1:1 blend of AYAA and AYAC type
    Polyvinyl Acetate resins dissolved in ethanol. They are
    exceptionally useful in art conservation, as they remain soluble
    in ethanol and other alcohols

    ...

    PVA Colors remain soluble in ethanol, making them ideal for easy
    removal without disturbing the layers of original paint
    underneath. For this reason, they are beneficial in art
    conservation for inpainting techniques.

Technical Specifications of Pure Resin System

    *   100% polyvinyl acetate, thermoplastic solution polymer.
    *   Average molecular weight: AYAA is 83,000 amu, AYAC is 12,800
        amu.
    *   Soluble in ethanol (95%), methanol, acetone and various
        ketones, acetates and lower alcohols.
    *   Insoluble in several glycols, hydrocarbons, higher alcohols
        and water.
    *   Refractive index (of neat resins) is 1.4665 (at 20oC).
    *   Softening point: AYAC at 71oC, AYAA at 97oC.

In addition, the Golden website has many other entries about the
conservation of acrylic dispersion and solution paints.  Worth a
visit.

Mark D. Gottsegen
Chair, ASTM D01.57
Associate Professor
Department of Art
UNC Greensboro
1203 NC 62 East
Climax  NC  27233-9183
336-707-3647
Fax: 336-334-5270


                                  ***
                  Conservation DistList Instance 19:55
                  Distributed: Saturday, May 13, 2006
                       Message Id: cdl-19-55-007
                                  ***
Received on Saturday, 6 May, 2006

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