All thirteen known Ruisdael etchings come from his early period, with the first one dated 1646. No etchings exist signed by his father, his uncle, or his fellow Haarlem landscapist Cornelis Vroom, who influenced his other work.His etchings show little influence from Rembrandt, either in style or technique.From 1646 he painted Dutch countryside scenes of remarkable quality for a young man.After a trip to Germany in 1650, his landscapes took on a more heroic character.However, Slive is willing to accept that Ruisdael may still have been a doctor. Slive reports that, because of Ruisdael's depiction of a Jewish cemetery and various biblical names in the Ruisdael family, he often heard speculation that Ruisdael must surely be Jewish.
Instead, Ruisdael places tree-covered dunes prominently at centre stage, with a cloudscape concentrating strong light on a sandy path.Few original impressions exist; five etchings survive in only a single impression.The rarity of prints suggests that Ruisdael considered them trial essays, which did not warrant large editions.The art historian Hendrik Frederik Wijnman disproved the myth that Ruisdael died a poor man, supposedly in the old men's almshouse in Haarlem.Wijnman showed that the person who died there was in fact Ruisdael's cousin, Jacob Salomonszoon. In a large sample of inventories between 16 the average price for a Ruisdael was 40 guilders, compared to an average of 19 guilders for all attributed paintings. 1646 to the early 1650s, when he was living in Haarlem, is characterised by simple motifs and careful and laborious study of nature: dunes, woods, and atmospheric effects.When De Goyer moved away to Naarden, three of his sons changed their name to Ruysdael or Ruisdael, probably to indicate their origin.By this time landscape paintings were as popular as history paintings in Dutch households, though at the time of Ruisdael's birth, history paintings appeared far more frequently.In total he produced more than 150 Scandinavian views featuring waterfalls.Ruisdael's only registered pupil was Meindert Hobbema, one of several artists who painted figures in his landscapes.For a landscape artist, it seems Ruisdael travelled relatively little: to Blaricum, Egmond aan Zee, and Rhenen in the 1640s, with Nicolaes Berchem to Bentheim and Steinfurt just across the border in Germany in 1650, Archival records of the 17th century show the name "Jacobus Ruijsdael" on a list of Amsterdam doctors, albeit crossed out, with the added remark that he earned his medical degree on 15 October 1676 in Caen, northern France.The Ruisdael expert Seymour Slive argues that the spelling "uij" is not consistent with Ruisdael's own spelling of his name, that his unusually high production suggests there was little time to study medicine, and that there is no indication in any of his art that he visited northern France.