One of those photos that raises more questions than it answers.
Two 78th Highlanders. It can be dated to post-1868 due to the gauntlet cuffs.
What interests me particularly is the piper's doublet, which appears to be coloured in like manner to the non-piper's, which would have been scarlet with buff facings. In any case the facings of the piper's doublet don't match the rest of it. One would expect the piper's doublet to be entirely Archer Green.
Also interesting is that I think it's the first photo I've seen of military men wearing Ghillie brogues.
The article about the history of the dress of the pipers of the 78th Highlanders contained in The Queens Own Highlanders Standard Setting of Pipe Music states that the pipers went to the Archer Green doublets in 1859. This green piper's doublet can be seen in this photo, which also shows that the gauntlet cuff was adopted first on the piper's doublets and later spread to the rest of the regiment. The 1855-1868 style of doublet can be seen worn by the other soldiers, with slash cuffs.
(Note the interesting bit of lighter-coloured tartan ribbon under the plaid brooches in both the above photos.)
And here's another 78th Highlanders piper.
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