Having had the occasion to establish the importance of alterations that affected the drawings forming a part of what is called “dessins d’ordonnance” in the collection of Everard Jabach in the Louvre, the author returns to that subject, this time dealing with laboratory photographs of the drawings. The photographs clearly show some reworking in the drawings by Lorenzo Lotto, Paolo Farinati and Giorgio Vasari. The aim of the present article is to focus the attention of the scholars again on the importance of taking those alterations into account while preparing records or technical descriptions of the works, as well as in the accompanying comments. It is not the question of diminishing the aesthetic value of a drawing but to precisely record all we can see. Laboratory examinations are, of course, exceptional and available to specialists, but the use of the eyes, simple examination in raking light and with the help of lighted magnifying glass, are available to everyone. In the Louvre every drawing called “d’ordonnance” from the Jabach collection should be examined with circumspection. The problem, of course, regards by no means only this collection or only the holdings of the Louvre. This awareness should be a reminder that drawings should be examined very carefully.