All true Robert, but even a chip made for choice can be "shot" into the computer and some formula generated based on whatever the available range of pigments might be. I'm not thinking of a CSRM / Smithsonian situation here; just what the average small volunteer museum can do as well as they practically can with what resources are likely to be available in their city.

I don't believe you have ever tried underthinking anything......which is one of the reasons I love reading your posts.

dave

As a note for people who are confused by the technical stuff, but want to find out more, here is a handbook from the architectural-preservation community:

http://www.iccrom.org/pdf/ICCROM_14_ARC ... k03_en.pdf

Something else to keep in mind: Although you may have a perfect color match today, in a few years your paint may fade very differently from another car you painted several years ago. Or if you painted only part of a car to cover a structural repair, in a few years your repair color may be different from the rest of the car.

Problems began as a result of laws requiring paint manufacturers to get the lead out. Many widely used pigments contained lead. Chrome yellow, for instance, is lead chromate. Most railroad green colors contained chrome yollow pigment.

Pigment manufacturers have developed organic pigments to replace those containing metals. These pigments have evolved over the years. Only recently has a good saturated yellow pigment become available. So the pigment in a computer matched color you buy today may be different from the paint you bought at the same store a few months ago.

A few exemptions exist. Artists and sign painters paint can still contain metal pigments. However the problems in keeping traces of metal pigment out of paint manufacturers machines that also mix non-exempt paint are so large that most paint manufacturers won't touch metal pigments. Also the market is too small.

Recently OneShot sign paint has phased out chrome yellow pigment. The paint color still is sold but it has organic pigment.

You might possibly be able to purchase old pigment paint overseas, but that raises many more problems.

Some years ago at Orange Empire Ry Museum we had a match made for the deep, dark red used by the Pacific Electric. The sample was from a location on a car body that had been a well protected from light.

One old-time PE employee/railfan said that the color was correct. Another one said that the color was wrong.

My response was to comment that "are we dealing with faded paint or faded memories?"
Or maybe faded memories of faded paint!

Brian - lol re: PE "red". Glenn Guerra had a saying that went something like "someone thinks he/she will get into heaven first because they know the correct paint color."

At NCTM when possible we've done as you have with trying to get the best match. When planning for the eventual paint job of Capital Traction 27 (a. CTCo 766), where no layers of paint clue us otherwise, we asked Roy King to head over to the Ben Moore paint store and pick the colors he thought were correct. Roy worked with historian Bob Truax and voila - we have what we think are the best match for the paint colors of the 1933 rebuild that we are aiming for.

Here's my favorite color story. The late Al Savage, VP of maintenance at DC Transit shared a painting secret. Weary of trying to keep a fleet color on the PCC trucks, he had the paint shop mix a color that matched reality - and called it "dirt". When the historically incorrect for the car Silver Sightseer painted trucks on DCTS 1101 get dirty you can see where he was headed - a tannish color that hints of red clay dust. And there is no color dip or fleet color code for that!

Wesley

Whereas human vision can differentiate many hundred of thousands of different colors, there is no vision equivalent of perfect pitch in music. Even a trained artist cannot reproduce a color accurately without some color reference.

An example of variability of vision is that for most people colors look similar under daylight as they do under incandescent light.

Eastman Kodak had a display used at fairs with a number of different color objects in a glass display case. Kodak would switch the light source. All the object's colors would change while a piece of white paper would appear to remain the same. This was used to promote Kodak color film.

San Francisco Municipal Railway had a barrel that was used to hold leftover paint of any color. Shopmen would dip fenders into paint in this barrel when repairs were made.

That is a problem that bedevils modelers -- if you match the actual paint (used outside in the sun), but under incandescent light or under florescent lights it will look different. Then to further befuddle a modeler mention the affect distance will have on the observed color (or gloss).

And that is the reason why, if you only want to do it ONCE, you will use a broad-spectrum light source of known peaks and characteristics (e.g. a tungsten-halogen lamp for normal 'visible' colors) and pull an accurate reflected spectrum with an instrument like a grating spectrophotometer.

Do not worry about 'paint matching' -- you can do that by empirical methods to match the spectral characteristics you've recorded, or use an expert system or chart system of some kind for 'best approximation' or 'least cost at the Benjamin Moore dealer/Home Depot' if that's the operational reality.

Note that this is a very different thing from tristimulus 'colorimeters' that approximate how a color appears to the human eye. It uses an easily reproduceable, universally-calibratable light source, and measures the exact reflection of ALL the frequency bands across the range of visible light. (In my not-so-humble opinion, you also want to get some IR and UV spectral data if there's any excited phosphorescence or frequency shift in any component of the paint -- I once had a car painted a rich bottle green with a yellow component that phosphoresced when exposed to UV, giving an interesting and subtle lighting effect...)

The point of the exercise being that you have described EXACTLY how to reproduce the effect of light reflecting from paint, and with a few mathematical transforms you can get reasonable approximation of how light of uniform perfect power spectrum reflects from that paint. It is then very simple to calculate (1) how the human eye will respond to light in that spectrum; (2) how the human eye will respond to the reflected spectrum from a 'different' light source; and (3) if you know the chemistry of your paint, how the reflected spectrum will be likely to change with aging, weathering, etc. HOWEVER you aren't going to be 'tied' to any of those interpretations, as you would be for example if you just matched color chips in ambient light, or ran one of those Pantone colorimeters that gives you the 'nearest' process color in gamut.

Take-home message: imho it is probably worth investing, ONCE, in a good grating spectrophotometer and known-quality light source, and use it to establish records for all the colors you have. (And that specifically includes the 'faded' existing versions, too, because you can at least in theory match those 'perfectly' from their present spectra, or back-translate to an original if you know how they have become faded or changed...)


RME

I recall an article in the last 20 years discussing how the change in paint "archaeology" impacted decisions during restoration of George Washington's Mount Vernon estate. Gone were the soft Colonial Williamsburg colors, replaced by brighter hues.

The best I could find was this article by Bob Vila, including this quote:


http://www.bobvila.com/articles/2240-historic-paint-colors/pages/1

The article is worth looking at just to see the dramatic change in colors of the dining room at Thomas Jefferson's Monticello.

Wesley

Dear Mr. Hees

Thank you for the offer but the purpose of this right now is to lay out the history of the locomotive and know where to find more information on certain details. With the evolution of 3420 to today’s configuration it is an SP locomotive but it is import to understand its history from its building and not just when I came to the project.

To Everyone

On the issue of exact color shade or tome. I strongly suggest people read Bob Richardson’s Rio Grande Chasing the Narrow Gauge where he describes painting cars in Alamosa. The differences in a color of paint because of a purchasing department’s economic decisions and the differences in manufacturing techniques are quite impressive. In the end it tells us if the color is close someone probably painted that color somewhere because it is what he had.

Robby Peartree

Dear Mr. Hees

I was asked the following privately

"Could you steer the conversation to the possible dates associated with the painting book in the Stanford Library? My sense is that many of the elaborate locomotive finishes disappeared by the late 1880s. That was certainly the case on the AT&SF, a very steady customer."

Do you have any info to answer these questions?

Thanks

Robby Peartree

The Stanford Baldwin Paint book (actually two books) was a hand made book telling the painters in Baldwin's shops how to stripe a locomotive. It is undated, but it was part of a painting system used from about 1874 to the early 1900's.

Several of us have suggested that It was made a bit later, likely in the mid 1880's to replace a similar earlier book.

On a Baldwin specification sheet you find a reference to paint, for example "wine and gold style 1"... The color name will be used on all painted parts unless the style calls for something else, wine frame, wine drivers, wine tender tank, wine cab (if painted) with gold leaf for gold colored striping and lettering... a second example would be "Lake and Color" In this case all painted is painted lake (a brown) and gold colored lettering would be yellow paint...

The book contains a table of paint styles starting with Style 1, and running to about 500 (this from memory) For each style the table calls out a cab, a dome, a cylinder, a tank (or tender) and a driver. Earlier styles don't include a cab. The book then contains pages with drawings of cabs, domes, cylinders, tanks, plus illustrations of Motors and headlights. Style 1 happens to be cylinder 1, dome 1, driver 1, and tank 1... Style 49 is cylinder 1, dome 1, driver 1, and tender 23...

The individual illustrations of domes, cabs, etc are painted in about 1/24th scale, on card stock with locomotive paint then glued into the book.

There is a headlight and a dome with no decoration... so, if you didn't want stripes, you refer to the decorated example in the book.

We would expect the earliest illustrations to be in Wine, later to be in Lake, later in Baldwin Green, but that is not the case for the earlier examples, leading us to believe the book was remade... luckily headlights have examples of all of the "official" Baldwin colors, labeled on the same page.

With the specification sheets, it allows you to track the changes in paint styles of one significant builder...

Randy