At 03:55 PM 5/15/2004 +0000, you wrote:

What makes anyone think that freight car paint didn't vary in color
from batch to batch from a specific manufacturer? I am thinking of 2
colors, freight car red (iron oxide red) and black.

Didn't the paint manufacturers shop around and buy raw materials
from different suppliers at the best price, just like the railroads
put out competitive bids?

My employer sells a coating based on a resin made from linseed oil.
The color on this stuff and color of the resulting dry coating vary
considerably from batch to batch in shades of amber.

We always thought that the color variation was due to growing
location and conditions (hot, dry growing season versus cold, wet
growing season for example) and plant strain (maybe there is more
than one strain of flax).

Ed Mines

I worked in a GM plant in the early '60s. They had great difficulty in keeping the colours within acceptable matching limits within the same plant, for parts that were sprayed at different locations and this was a very important aspect of their operation. And, they were certainly using the most advanced technology available at the time.

Al Welch