Re: Engine 361 Closeup - Ex-Sperry-Ments ...

Hello, Jerry -

The photo that Rich posted has a decided magenta tint to the building in the background,
which I presume should be plain gray steel or "tin", but the dirt in the foreground is bluish.
I made a copy of the photo, and tried eliminating these tints by manipulating the over-all
color of the entire photo - not just a masked-off section - but then everything else turned
green - not just the boiler jacket, but the smokebox, cab & tender, and even the sky. It
seems that Rich's copy - at least - has deteriorated over time, and its original colors will
likely never be determined exactly.   I presume the original slide you scanned is at the
CRRM in Golden??

Another factor is the human eye's (or brain's) tendency to compensate colors. The magenta tint of the building causes the boiler jacket to look greenish by comparison. Displays of meat at your local market are surrounded by green trim for the same reason - the green border contrasts with the meat, and makes it appear redder.

- Russ

p.s. The angle that the sun is hitting the boiler jacket is in general not at all the same as the angle on the cab, tender or domes - but the cylinder jacket is curved just like the boiler - and would also most likely have been painted with the same heat-resistant enamel as the boiler jacket but unlike the cab and tender - yet the cylinder jacket appears far darker than the boiler jacket ...   I still can't help wondering 'why?'.

Here are both three versions - Rich's original, my attempt to turn the building gray by adjusting the color of the entire photo, and - per Dave's suggestion in [ngdiscussion.net], below - darkening the whole photo to make the building redder and then decreasing the blue to get rid of the foreground tint:




The third photo is far from perfectly balanced, but it's pretty clear that when the cab & tender are closer to black, the jacket appears closer to gray - not green.



Edited 2 time(s). Last edit at 03/07/2010 11:32AM by Russo Loco.