Find out more: A few comments on visual search criteria

Initials and words (Latin alphabet): these may be characters actually contained in the mark as well as ones that seem to be decipherable. Carrying on Lugt’s practice, it is specified in the body of the article how the mark should be read.
Initials and words (non-Latin alphabet): this is for example the case of initials and words in Cyrillic characters. If the appearance of these characters lends them to confusion with alphabetic characters, double indexing allows them to be found in both categories.
Japanese characters, as well as Japanese-inspired marks. It should be noted that marks of this type stamped on Japanese works are not listed.
Number: this may be a date, an inventory number, a price code, an address, etc. To limit the number of responses, it is thus advisable to combine this criterion with other search criteria.
Paraph: written sign where the characters are not identifiable, or are difficult to identify.
Writing sample: these are handwritten comments generally added to the verso of drawings and prints, whose writing is characteristic of a set making up a collection.
Human body: or parts of the human body.
Geometric figure: the main geometric figures present in a mark, including the contours as well as the shapes within the mark.
Object or representation: to limit the number of responses, it is advisable to select, in the scroll-down list, a specific object, or to combine this criterion with other search criteria.
Coat of arms: search for elements present in coats of arms (for example, crowns or shields) in the Object or representation criterion.
Technique: the one used for stamping the mark. For example, a label is considered to be an affixed mark and a wax seal, a stamped mark.
Colour: for each mark, the colour has been indexed (verified or indicated by a third party), but other variations may well exist. It is possible that the reproduction does not match the information given in this section, as the marks in certain images have been transmitted in a different colour from that of the original.