X-ray techniques date Rembrandt prints precisely

“In Sotheby’s N.Y. last May 28 out of 80 prints were later impressions”



Nine out of every ten etchings by Rembrandt were printed after his death, the last edition appearing in 1906. Some of the plates had been sold to publishers and other artists during Rembrandt’s lifetime, and they, no doubt, are also responsible for at least some of the prints executed before 1669, the year of Rembrandt’s death.

The eighty-one plates still extant and now in the possession of the museum of Raleigh in North Carolina, were acquired during the eighteenth century by the French amateur engraver Claude-Henri Watelet who in turn sold them to Pierre-François Basan. He and his son are largely responsible for the countless impressions of Rembrandt’s graphic works, repeatedly reworking the plates so that Rembrandt’s authorship of them has become something of an ethical dilemma. This has caused the prices of Rembrandt prints to vary significantly according to the date of the impression. Another factor to complicate the issue, are the forgeries on the market made from nineteenth- century heliographic reproductions printed on seventeenth- century paper.

This is where the newly established Foundation for Paper Research has stepped in. In 1968 the art historian Biorklund dismissed the usefulness of watermarks in the authentication and dating of Rembrandt prints, the reason being that there were over 400 of them and that no clear pattern had emerged with regard to the dating of the prints themselves. The general consensus on this matter was left undisturbed until 1984 when Mr Theo Laurentius, an art dealer who specialises in Rembrandt prints, became convinced that the paper on which the etchings were printed did after all hold the key to their authenticity and thus to their value.

The problem was, however, that the ink often obscured the watermark as well as large sections of the paper which could show up the idiosyncrasies of the particular mould used (the point being that the hundreds of paper mills in existence at the time not only had their own watermarks but that each particular paper mould had its own variations in the structure of its wires). These differences could obviously prove useful in identifying batches of paper made by the same mould. On top of this it is known that any one mould would only be in use between seven and fifteen years. All these facts concerning the particular mechanisms of the paper industry added together meant that it was quite unlikely that Rembrandt would buy two batches of paper prepared by the same paper mill using the same mould.

Laurentius discussed the problem with his dentist Mr van Hugten and together they experimented with various methods of X-ray photography and beta-radiography in order to record the structure of the laid paper accurately, without interference from the ink. Now they have developed, with the help of Professor Van Aken of Utrecht University, a simple method of Roentgen photography, whereby a low-powered X-ray (220 volts exactly, which are converted to 5000 volts) passes through the paper and exposes the negative directly behind it to the exact amount of radiation needed to show up the detailed structure of the impression left by the mould and the watermark.

Now Mr Laurentius travels about with an antiquated set of hospital X-ray equipment with which he is able to take a detailed picture within seconds. In collaboration with Mr Filedt Kok and Mr Pieter Schatborn of the Rijksmuseum in Amsterdam he has photographed the complete collection of Rembrandt etchings in the printroom, making some 2000 exposures, and has been able to put together a detailed picture of Rembrandt’s use of paper.

For his drawings Rembrandt made use of any old piece of paper lying about which was suitable. But because of the nature of the printing process, Rembrandt was both methodical and economical with the paper he used, buying a ream (480 sheets) at a time, and often printing three etchings onto one sheet. Thus it is possible to build up an accurate map of which etchings were printed together and so establish their place in a general chronology. This systematic approach has now reached the stage that Filedt Kok, Schatborn and the initiator, Laurentius, feel that the time is ripe to publish their findings and the conclusions which can be drawn from them. A book on the subject is expected within a year or two.

The research has already revealed some interesting facts about Rembrandt which have hitherto been overlooked. For instance the chronological grouping of particular watermarks has revealed that a small portrait of Petrus Sylvius, Saskia’s cousin, was printed twice: once in 1637, which is the date below Rembrandt’s signature—this was on the occasion of Sylvius’s move from Amsterdam to Friesland after he had been received as a minister of the church—and again, in an unaltered state—still carrying the date of 1637—much later, in 1653. This turns out to have been the date of Sylvius’s death.

Laurentius is now collaborating with the technological giants Philips in Eindhoven to perfect the image of the X-ray using computer-boosting techniques, so that a clear positive print of the watermark and the structure of the paper can be achieved.

The establishment of the Foundation for Paper Research last August initiated a programme whereby certificates of authenticity, under the control of a board of trustees, are issued with every Rembrandt print passing through the Foundation. The first certificate was issued in October. All in all these developments have had a very mixed reception. The auction houses may anticipate an effect on prices, although early and late impressions are already clearly differentiated in catalogue descriptions. According to Laurentius in fact, twenty-eight of the eighty Rembrandt prints offered for sale by Sotheby’s in the spring sales in New York last May, were late impressions. Less forgivable is the attitude taken by some museums who are frightened of the consequences of having their collection screened.

One collector even suggested to Mr Laurentius that no one was really waiting for these new techniques and that it would be better for everyone if he stopped. But it is too late for that now.