Bearing a faint pencil notation on the reverse side that reads "July '00" and a later ink notation of "Andy Imlack", I believe this photograph depicts Andrew Alexander Imlach while  
member of the Canadian Militia sometime in the early 1900s.

Andrew Alexander Imlach was to son of Scottish immigrants Andrew Imlach and Mary Anne MacKenzie. Born on 18 August 1882 at Carleton Place, Ottawa, Ontario Imlach would
rise to local prominence as the president of the Victoria Foundry Company, Ltd.. Interestingly I can find no reference - aside from this photograph - mentioning Imlach serving in any
Canadian Militia unit. Additionally Imlach's rather long June 1937 obituary which appeared in
Ottawa Journal makes no mention of him serving in the military. That the man in the
photo is indeed Imlach there is little doubt due to the unmistakable resemblance between this photo and that of an older Imalch that appears with his obituary (below). It is possible that
his military career was simply too short to figure much in the life of this icon of early 20th Century Ottawa industry.

Andrew Alexander Imlach married Miss Helen Pittaway of Ottawa on 2 March 1902. The couple would have three daughters and one son.  

Interestingly, this photograph of Andrew Imlach was taken by Ottawa photographer Alfred Pittaway - the father of Andrew's soon to be bride Helen.  

The uniform Imlach is pictured wearing is described in
Scarlet to Khaki as that of the 5th Princess Louise Dragoon Guards His tunic would have been scarlet with a white collar, yellow
shoulder straps and gold trefoil cuff braid. The trousers would have been dark blue with wide double white stripes on the outside seams.

Mounted Photograph
Alfred Pittaway - Photographer
Ottawa, Canada
c. 1900
Right: Andrew Imlach's likeness as it appeared in his 22 June 1937 obituary
which was published in the Ottawa Journal. Source: newspapers.com