• FAQ DETAILS

  • What is a Substrate Induced Discoloration (SID)?


    When acrylic mediums are used as a size for some primed or unprimed cotton, linen, wood or hardboard, the water content may draw impurities out of the support as it dries. A yellow or brown discoloration in the medium may occur over time. It will only be noticeable in areas that are left unpainted. It occurs with all acrylic mediums currently used by major fine art paint manufacturers. Washing the canvas before use can greatly decrease or eliminate SID. It is not a problem if the mediums are mixed with paint or painted over.

    The amount of discoloration in the acrylic medium will vary depending upon:
    1. Quality of the acrylic medium. The unique resin formulation used in all Liquitex® paints and mediums is clear, flexible and non-yellowing.
    2. Thickness of the medium application. Gel mediums are more susceptible to SID than fluid mediums. They are thicker, contain more water and take longer to dry.
    3. Substrate used. Different surfaces contain different colorants and contaminants.

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