Re: Freight car colors...


Doug Dolloff
 

The way that paint is mixed is by weighing the different colors. It is not by a 50/50 or 25/75 ratio. Different paint colors way different amounts, therfore you may add 5 grams of color A and 20 grams of color B to get color 25 grams of color C. This is how automotive paint is matched aswell as most house paints. You can use weight ratio like 5 parts part A + 20 parts of B = 25 parts of color C. That way anyone can use a weight ratio to get the same color, wether they are using grams, pounds, wheelsets, etc.. Paint pigments weigh different amounts. Typically yellow pigment paint ways more than blue or black because it takes more pigment to create yellow than blue or black. Weight is the only way I know of to accuratley tint or change the tint of any color and be able to recreate the same color later or to tell someone else how to recreate the same color.

I hope this helps.

Doug
Rob Kirkham <rdkirkham@...> wrote:
Gee that is a creative idea Jack, but unfortunately, I don't think the
electronic mix will give you any useful information. While I'm not really
up on the pigments used in model paints, use of artists paints can be a
revelation. We were all taught in grade school, for example, that red and
yellow make orange, blue and red make purple, etc. But with paints, they do
not always react with each other the way these generalisations suggest they
should. Blue and red do not always make purple - it depends on the
pigments. And those that do mix to purple certainly don't all make the same
purples or make the purple someone new to the pigment might expect. The
result is that the theoretical formulations of colour manifest in light on
your computer screen do not mix in the same way as actual pigments - and so
won't predict the results of the mixes of real pigment.

Rob Kirkham

----- Original Message -----
From: "Jack Burgess" <jack@...>
To: <STMFC@...>
Sent: Wednesday, May 14, 2008 4:11 PM
Subject: [STMFC] Freight car colors...

Mixing paint to match a paint chip, a paint sample, a photo, or memory is,
for me, very difficult. One could obviously prepare 50/50 mixes of all
possible combinations of one manufacturer's paint line but there are also
possible combinations other than 50/50 and 50/25/25 possibilities.

I've given a lot of thought to how that might be done "electronically".
Unfortunately, I haven't been able to find a program to take samples of
paint color and easily "mix" them. However, I have played with the
Gradient
Tool in Photoshop (also available in Photoshop Elements). If one scans
painted samples of two paint colors, such as Floquil Boxcar Red and
Floquil
Tuscan, and open the scans in Photoshop, the Eyedropper Tool can be used
to
load those colors as the Foreground and Background color. The Gradient
Tool
can then be used to "mix" the two colors and produce a 50/50 or 25/75 mix
or
any other proportion electronically. The resulting mixes can be saved as
color swatches and so labeled. By scanning all of the available "reds"
from
one manufacturer, one could produce swatches of all possible variations.
Samples of the prototype colors could also be sampled and compared to the
mixes.

I need to develop a variation of boxcar red to match the YV cabooses I
painted many years ago (unfortunately, I didn't keep track of the
proportions back then) for a project I'm working on. I'm thinking that a
good test for the process would be to mix two reds electronically and also
physically and compare the results.

Has anyone done anything similar? Was it successful?

Jack Burgess
www.yosemitevalleyrr.com

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