Help evaluate the picture on the board, on the idea of someone from the Dutch
 

The picture on the board, looks very old, say that the work of the Dutch :)

Before asking a question about the assessment, you would think was worth, but whether, in principle, any substantive response only on such basic information? For those black spots - photos that you have given - generally do not convey any information.

Try again photographed, in daylight, not in the room.

A good idea to specify the types of wood, thick planks, the direction of fibers and the presence (absence) facets at the edges, board, whole or composite, monogram (signs) on the back (if any), the presence levkas on the back of the board.
If the paint is practically impervious to the photo and if the dimensions allow, try to scan.
At least in part, including inscriptions and signatures (if available).

well, I'll try that - do something, but the board from both sides is very dark, and I have no doubt that the whole, though I certainly will check it.