Dating old photographs 1850
The inner and outer baileys and the great keep belong to this time.
Maurice the Engineer was responsible for building the keep, one of the last rectangular keeps ever built.
Some halftone cards were printed on high gloss paper to resemble a photograph but their screen patterns will give them away if one is vigilant.
In printed images the grey areas are usually made up of black marks that are spaced to create the optical illusion of greys.
Though most of us today are familiar with the concept of photo grain, this is mostly because we have experienced very large prints made from small 35mm negatives.
Many cabinet cards feature the name and location of the photographer printed on the front of the card underneath the picture.
Some have fancy backmarks advertising the photographer (this trend increased towards the end of the century when advertising became commonplace), whereas some have no markings at all.