Bruce Smith wrote:

The colors on the PRRT&HS drift cards were printed using the best available matching technology of the time. Chuck Blardone sat under a tree on a sunny day (diffuse sunlight for lighting) and matched samples.

Good story, Bruce.
I well remember, when working on the PFE book, to have been allowed to view a historic sample at the old UP Museum of the original (pre-1929) PFE yellow paint. The person from the Art Department who was helping immediately pulled out a Pantone matching book and we made a pretty good match in her office. Then she said, "We're not done," and we went down in the elevator to the street and walked outside into the Omaha summer sunshine. We matched again--and found a distinctly different Pantone match! I was surprised at the EXTENT of the difference, and upon returning upstairs, again found the original match to verify our original perception.
Anyone who says they "know" a color or can "match" a color, without reference to environment, is ignorant and uninquisitive.
One option, as we did in the PFE color drifts, is to use a "true light" booth, but that doesn't exactly match either average sunlight or indoor light, certainly not most layout rooms. It's a good average and more important, it's reproducible. But in a sense, it's not the "right" color.

Tony Thompson Editor, Signature Press, Berkeley, CA
2906 Forest Ave., Berkeley, CA 94705 www.signaturepress.com
(510) 540-6538; fax, (510) 540-1937; e-mail, thompson@...
Publishers of books on railroad history

Perhaps, we cannot in any sense come up with the "right" color. We can only
do our best, come up with what we perceive to be a perfect match, and resign
ourselves to being blasted as wrong by someone whose perception is as valid
for them as ours was for us.

Regards,
William Bryk

--- In STMFC@..., Anthony Thompson <thompson@...> wrote:

I well remember, when working on the PFE book, to have been
allowed to view a historic sample at the old UP Museum of the original
(pre-1929) PFE yellow paint. The person from the Art Department who was
helping immediately pulled out a Pantone matching book and we made a
pretty good match in her office. Then she said, "We're not done," and
we went down in the elevator to the street and walked outside into the
Omaha summer sunshine. We matched again--and found a distinctly
different Pantone match! I was surprised at the EXTENT of the
difference, and upon returning upstairs, again found the original match
to verify our original perception.
Anyone who says they "know" a color or can "match" a color,
without reference to environment, is ignorant and uninquisitive.

The proper name for the phenomenon of colors matching under one light
source but not another is "metamerism". Anyone who wants more info can
Google that word.

Back in the days before computer color matching, colors were matched,
by eye, under the light the application would be usually viewed under.
For exterior paints, this was obviously daylight. Each paint company
had a chemist or other production manager who had final say on
matches, but everyone perceives color a bit differently, so the
matches from different manufacturers would be slightly different. In
addition, one of the ways a supplier could win a contract and still
make money was to figure out a combination of less expensive pigments
that still yielded an acceptable match. The railroad's purchasing
department of course also had a say in this, but I suspect on many
roads the criteria were on a sliding scale; touch-up paint for those
shiny new streamliners was supposed to match, while freightcar paint
was just supposed to be close, especially if a cost factor was involved.

In addition, at one time some roads were less concerned about color
than content; reportedly PRR DGLE (Dark Green Locomotive Enamel) was
green because of the copper salt content. The color was a greenish
black not because the Pennsy wanted green, but because they wanted the
copper content, which made the paint a better preservative. The color
was a byproduct of the function.

Of course, as paint chemistry became less of an art and more of a
science, color consistency became better, and it was expected that the
colors should be at least a "commercial match", but even today this
level of color matching allows noticeable batch-to-batch variations.

Dennis (who uses Floquil – every gallon a new experience – Pollyscale)
Storzek