Two cdvs from the early 1860s, one with text on the front, the other with it on the back. Whether this change was deliberate or not is unclear. This form of lettering was used by others such as Urie and Turnbull at the same period.
The cdv above carries a beautifully sharp and well exposed image. The product is marred only by a fingerprint above the head. It must have been difficult to avoid this in the process of placing the delicate and perhaps moist paper tissue on the card. The card used is thicker than the two above, suggesting a slightly later date.
The two portraits above, on the basis of the thin, square cornered, thin card, the full length framing, and the simple logo on the back would come from the mid 1860s or even earlier. A similar logo was in use by other photographers in Glasgow in 1862. The chair in the second somewhat water stained picture above looks like the one on the left at the top.
Another two cards from the mid 1860s, one of which carries a date of 1866. The second, and later one states at the bottom that such pictures can be enlarged up to life size, and finished in oil or watercolours.