Re: Fugitive pigments

From: Katharine Thayer ^lt;[email protected]>
Date: 07/25/05-04:44:48 AM Z
Message-id: <>

David & Jan Harris wrote:
> Given that watercolour pigments are affected by light, and when we expose a
> gum print we expose the pigments to a lot of UV; probably more UV light than
> a watercolour print probably gets over a period of a year; will some of the
> pigments already have faded by the time we have finished a gum print, or
> would more occur later? I know this will vary with different pigments, but I
> am interested in the general rule. Do manufacturers test the pigment by
> intense exposure to light (or UV)?

Hi Jan,

Interesting thought, but I don't expect the amount of UV a gum print
gets in exposure would be very significant with regard to fading. It
depends on the light of course, but in my experience most lights we use
indoors take longer exposure than direct exposure to the sun does, so I
would deduce from that that in general, exposing a gum print with
whatever light would give it the same or less UV than exposing it
directly to the sun for the same amount of time. Certainly a few
minutes exposure to the sun shouldn't cause any noticeable fading.
Received on Mon Jul 25 11:40:46 2005

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