Most of the photos that I have seen by GR Mackay are postcard
portraits from the period 1909 to 1921, from his studios at 25 North
Bridge and 70 Leith Walk.
However, the carte-de-visite above is from his earlier studios at 105
South Bridge, where he was based from 1902 to 1908, towards the end of
the cabinet print and carte-de-visite era.
They show how different styles of photograph and mount were coming
into use in the early 1900s, but using the carte-de-visite size of
mount, to enable the photos to fit into the standard size of
photograph album that had been used throughout most of Queen Victoria's
The backs of the two photographs above are both plain white.