Hi I got this off Facebook. From my basic research it said that the reproductions have the shield on top of the glaze at the back. This one doesn't have glaze on the back. Only the sides and face. Looks like someone like to use the bottom right hand corner to put their tea cup. Interested in any verification or information that people can help with. Thanks very much
I think I can help with this. For the mark, try Oscar Schlegelmilch (after 1892) https://www.theoldstuff.com/en/porcelain-marks/category/205-oscar-schlegelmilch-marks This is a green mark. Yours looked bluish in the photo. Is that the lighting or is it really blue? For the design: It is based on an Angelica Kauffmann painting in the Metropolitan Museum of Art, Telemachus and the Nymphs of Callisto (1782). Besides history painting, Kauffmann made designs for china, and her work has been reproduced (more crudely) on porcelain from the 18th into the 20th century. (Maybe it still is?)
Here is the link to the Angelica Kauffmann painting in the Met: https://www.metmuseum.org/art/collection/search/436810 The design on your tray is based on the right (viewer's right) side of the painting with the seated Telemachus surrounded by nymphs.
If your mark really is blue, then it is more likely the Ackermann & Fritze mark. I immediately thought of Oscar Schlegelmilch's green mark because that is on my Angelica Kauffman design plate with similar decorative designs around the edge. But lots of porcelain factories used Kauffmann designs.
The top 2 marks on your factory page are the same maker and the same dates. From the decoration, it would be at the earlier end of the date period. If there is an indentation for a cup then it might have been the tray for a breakfast set.