This reverse design is presumed to be the earliest, on the basis of the sparcity of text and simplicity, probably from the first year or two at this address.
Herr Wohlgemuth seems to have been conservative in his use of designs, which makes it difficult to sequence his products. The cdv above is placed first solely on the basis of a thinner backing card, and the use of the title.
We can only say in relation to the cards immediately above and below that they each probably precede 1885, when the practice became Wohlgemuth & Co. The one on the right below is probably the latest, having a gilt edge.
A very sober class, probably in front of their school. The miniscule writing at the bottom of the back tells us that the card was supplied by the Glasgow printer George Mason, so we can say that the date is probably later than 1883. Wohlgemuth seems to have specialised in class portraits.
Obviously again before the days of saying 'cheese', this style of reverse design with the fine filigree patterns is associated with the mid 1880s (see for example Turnbull & Sons).