Dating of couple pictured - either Muir or Ross

[cosmac]

This unidentified picture is possibly James Muir (1834-1905) and wife Agnes Ross Graham (1832-1895).  Both lived in Larkhall, Scotland but James later moved to Holytown.

Another possibility would be Agnes' parents.  James Ross (1778 - between 1841-1851) and Margaret Graham (1795-1873).  Again both residents of Larkhall, Scotland.

I know nothing of clothing styles etc that help date pictures.  My guess would be the first couple.

[japeflakes]

I am guessing 1890-1900

[Treetotal]

My guess would be 1880s
Carol

[jim1]

It would be helpful if we could see all of it & the back in RGB.
The dress styles are typical 1860's but as an older couple they might be a bit out of date so could be 70's.
The pose is more suited to the 60's however the cardstock lettering is typical 1870's, hence the opening comment.