The date ranges refer to the periods
when the photographers operated from the appropriate address. They
did not necessarily use the style of back shown below through the whole of
the period shown.
The studio address of the previous photo is 60
Princes Street. This was Howie's studio 1864-67.
However, the style looks more typical of mid-1870s
to 1880s, so Howie appears to have been using 60 Prince St on his
cdv's when his studio address was 60b Princes Street, 1868-89