Why are there color variations in tin litho pieces.

Lithography is probably the single most fascinating aspect of traditional tinplate toy trains. I really wish I could learn more about it. What I have found online is more to to with paper or ancient times stuff with the one Darstad video being the exception. Thanks for the post, every little nugget helps. Tim

Very interesting. I know from past experience that humidity can play havoc with offset printing on paper, so it makes perfect sense that it would also affect the ink when printing on tin. I remember temperature also played a part in the chaos of getting the day's printing jobs started. Too cold and ink did not want to flow well either. Even though we had an electric offset press, printing was still more of an art than a science back then. Makes me appreciate how easily I can print stuff from my computer these days.

That is very interesting Steve...and explains alot. I've collected older tractors for years and years and tractors from the same company can also have variations. I've always thought some just "faded differently" over time, but sounds like they may have been a little different right from the start. I can't quite explain it but the older colors had a "depth" to the color that most definately adds a touch of class.

I am originally from a town called "Galena" and as the name implies the town was formed because of the huge lead that was mined there back in the mid 1800's.

Here is a question for you guys...and I'm willing to bet everyone knows this but me. Why was lead put in paint to begin with? I've wondered this in the past and have the following idea's but I don't know the answer:

Was it just used as a "filler" to make the actual paint go further? or did it make paint stronger and longer lasting? Or did lead actually help make the colors what they were somehow? You hear alot about lead being in paint, but I wasn't sure exactly how much lead was found in say, a gallon of paint. That alone might answer my question I guess...very interesting though.

My late father talked about painting the family home, probably in the 1920's. He said that the (white) paint and lead powder were purchased at the hardware store in town and the lead powder was added to the paint. He did not mention a ratio and I didn't think to ask about it. He did say that the purpose was to add durability to the applied paint. I imagine the lead was handled in a very casual way by today's standards.

Bill

 

There is also the fact of lot-to-lot variation in paint color which will result in tonal differences.  If color uniformity was a serious issue as far as your product was concerned then you would have in place a sampling plan and the QC lab would check lots for color uniformity.  For example, Kodak ran lot checks on every batch of pigment that was to be used to print the boxes for their film. Their specs were very tight because if the color of the film box was too light customers would assume the film had been sitting on the shelf too long and would not buy it.

at work I see the pressman struggle at times with color variations.sometimes the simplest things can cause a change.

i think lead was in paint for adhesion to the surface.