From: Katharine Thayer (kthayer@pacifier.com)
Date: 09/11/03-08:05:20 AM Z
Jack Brubaker wrote:
>
> Katharine wrote:
>
> a transparent gum print owes its "life" to light
> > going through the gum, striking the white paper, and reflecting back to
> > the eye through the layers of gum.
>
> It is this double passage of light through the paint that gives the tone we
> see. So a "transparent" layer can appear as "opaque".
To perhaps beat a horse that's already long dead-- I disagree with this
part of what Jack says for the very reason that it conflates density
with opacity in the same way that I've been arguing against. A
transparent layer can appear very dark, as he rightly said, but it will
never appear opaque, because as dark as it is, it will always reflect
back some light from the paper through the gum and pigment, whereas
opaque paint will simply not do that. Because of its opacity, it covers
the paper in a way that doesn't allow the light to go through the paint,
but instead the light reflects off the surface of the paint. It's two
totally different effects. Transparent means transparent, opaque means
opaque. Transparent means capable of transmitting light, opaque means
incapable of transmitting light, or as the dictionary says, "not
transparent." A thing can't be both transparent and opaque at the same
time.
Either transparent or opaque paint can be light or dark; density is a
separate issue from opacity. I guess that's about the tenth time I've
said it and I guess I'll give up now.
Katharine
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