From: Katharine Thayer (kthayer@pacifier.com)
Date: 09/12/03-05:44:06 AM Z
Jim Morris wrote:
>
> Perhaps, against my better judgment, I will take a stab at this. Could
> it be that the confusion is due to the different use of the term
> "opacity" viewed from a scientific stand point verses the artistic
> stand point? Many painters might consider "opacity" to mean, for lack
> of a better definition, covering power. In other words, if I paint a
> piece of paper with a dye based ink - let's say cyan- I can achieve a
> deep cyan color but I would also be able to see the characteristics of
> the paper on which it was painted; on the other hand, if I paint the
> paper with white latex paint, the paint may completely obscure the
> surface of the paper underneath becoming a new surface itself. In this
> case, if we were to define "opacity " as "covering power", the latex
> paint would be lighter and more "opaque" while the cyan ink would be
> darker and more "transparent".
>
> Yes, no, maybe?
>
Yes, no, maybe. To me the crucial difference between opaque paint and
transparent paint is the transmission or nontransmission of light
through the paint, which is the scientific definition of opacity, no? A
paint that's opaque in that sense will also have covering power; I'm not
sure it's possible to have one without the other. I would say that
opacity and covering power, if not precisely the same thing, vary in
tandem. Your example above is correct, that a light paint can be opaque
and a dark paint can be transparent; that's what I've been saying all
along, but I don't understand what point you're trying to make by trying
to distinguish covering power from opacity. Your last sentence above,
would be correct either way, whether you define opacity as ability to
transmit light or as covering power.
Katharine, who needs to get up from the computer and go buy some tires.
Katharine
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