I'm guessing that the piece is about 8" diameter, although if the actual size were different this would not have a bearing on my comments.
This looks to me like a typical studio piece by a competent maker that is likely to have been made within the past 25 years. It could have been made by a studio owner, but equally by an assistant, or indeed a student at one of the art colleges (now universities) with a glass department.
Without being able to identify the signature and thereby attributing it accurately, it is not possible to say whether the maker, (ie the blower), was also the same person who did the cold worked decoration. It is quite possible that there the decoration was done by someone else. Many engravers commission or buy bowls like this from makers and work on them in their own studios.
From what I can see from the photographs, I think it is most likely that the decration was sandblasted, and not acid etched. The style of decoration suggests that the resist used was probably PVA glue which can be used squirted straight from the tube or bottle, but there are other ways of achieving this.
From time to time comments come up on the board regarding types of decoration and acid etching is often cited alongside sandblasting as an alternative. As a general rule (to which you will always find exceptions), most studio work of this genre is more likely to be sandblasted than acid-etched. Sandblasting is a bit like using sandpaper on wood....you can get different grades of abrasives so you can create different textural effects, and the finer grades, together with brush polishing with pumice or cerium can give a very satisfactory finish which is often mistaken for acid etching. Another way of getting a silky finish is to hand polish after sandblsting with various grades of diamond pads. This can be time consuming but achieves a fantastic "soft" surface that everybody assumes has been achieved with acid.
Most people don't have access to acid facilities.
I wonder whether "inka" could a signature of a nickname or shortened form of something like "katinka"?