BR 2mt 78022

Pre-grouping and freight vehicles yes, but locos in BR days? I'd like to see some evidence before believing that, my understanding was that by then it was all factory produced and brought in.

 

To a large extent that was the case but there would generally be a swatch of the standard colour for the one mixing the paint to compare it with. Those mixing the paint would be fairly expert at it as it would be a daily chore. I suspect that the variations from batch to batch weren't significant.

 

Bought in, maybe, but there was no computer controlled mixing and it would still largely be down to the human touch. Even with modern mixing equipment, there can still be noticeable variations from batch to batch if they are used on the same panel. I'm sure that you have experience of this.

 

Though you then have to add the effect of age; lead-based paints tended to darken (because they absorbed atmospheric sulphur to form lead sulphide, which is black). Modern synthetic pigments tend to degrade with UV light, causing them to gradually get lighter with age rather than darker as before.

Tom

 

Indeed, I definitely have experience of this. Can't say I've ever noticed any difference when starting a new tin half way through a job, I'm sure Williamson's will be pleased!

 

Blue paints of old certainly lightened in use, the main reason BR went off the original express passenger livery. The BR corporate blue did the same so they hadn't learned the lesson or had forgotten. The KESR found the same when they painted their locos blue in the early days. DidBluebell suffer the same, I wonder. Having said that, I don't think modern blue paints suffer in the same way.

 

I clearly recall the darkening effect on pre-woad era BR(S) EMUs, which was very noticable when a newly outshopped 4EPB was coupled to one in 'tired' green. From memory, BR 'rail blue' didn't age any too well either.

A sometime acquaintance of mine, a panel beater/sprayer by trade, always held that red shades were worst for weathering, with yellows coming in a close second.

Another thing affecting paint is, of course, temperature. Former MSWJ paint shop wallahs despaired of the GWR's standard allocation for repainting, commenting that it would need so much thinning that it'd turn black on boilers in no time flat. Swindon, on the other hand, were distinctly dischuffed at the 6 weeks the MSWJ shop routinely took to repaint a loco.