Here is an etching postcard which is a little different from the others. The technique on all of the previous cards has been hard ground etching. With this kind of etching, the protective ground on the copper plate is a hard wax, or asphaltum material. The lines and dark areas of printing are precise, because the etching tool only removes the ground where the point of the tool meets the bare metal. During the actual plate etching process, the acid bath only removes these precise areas.
This postcard is a combination of soft ground and hard ground etching. It appears that the artist first did a soft ground etching, and then to darken the shadows on the left, and to add a few details, the plate was re-worked. It was covered with a hard ground, and that work was done.
The close up pic shows the carriage, pedestrians, and shading on the church in the middle as being soft ground etching, while the darker, more precise lines on the shadows of the left foreground are the work of hard ground etching.
Soft ground etching almost has the appearance of lithography, a planographic technique done on a limestone surface.
From oxfordreference.com, "(Soft ground is) a method of etching that produces prints characterized by softness of line, or grainy texture. The waxy ground used to coat the plate is softer and stickier than in normal etching, so that it adheres to anything pressed into it. Over this ground is laid a sheet of paper on which the artist draws with a pencil. Under the pressure of the pencil strokes, the ground sticks to the back of the paper, so that when it is lifted, the wax underneath the lines comes away with it, while the rest remains in place."