Relative whiteness of paper

I was wondering if there is some product that will help to visually
determine the relative "white" of a given paper?  I am photographing
watercolor paintings that where recently given to the Institute.
The paintings are on what visually looks like "white" watercolor
paper, but they have a slight blue cast to them in the photographs.
There is Kodak color chart in the photographs that has a white patch
that is "white" in the photographs which verifies that the blue cast
is not a bias in the film, but a characteristic of the paper.  I
suppose a densitometer can do this (?), but for those of us that do
not have one it would be helpful if you could show someone visually
that a paper has a warm or cold bias.

Frank A. Reynolds
Hunt Institute
Carnegie Mellon University

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                   Conservation DistList Instance 9:9
                   Distributed: Friday, July 14, 1995
                        Message Id: cdl-9-9-004
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