Abstract: A method for obtaining information about a layer of an organic solderability preservative on a printed circuit board, the method including Providing or producing a printed circuit board (16) having a copper layer (18) covering a part of an area of the printed circuit board (16), Providing a fluorescence measuring system (10), the method including following steps a) Obtaining (S2) information about the location of the openings (21) on the printed circuit board (16), b) Selecting (S3) at least one of the openings (21), thereby obtaining at least one selected opening, c) Moving (S4) the radiation source (11) and the printed circuit board (16) relatively to each other, d) Detecting (S5) the fluorescent radiation (23).