As a keeper of the Franeker Westerpoort, Pieter Idserts enjoyed the assurance of a fixed income. Gatekeepers – portiers – were appointed by favour of the magistrate and the post was usually reserved for family members or friends of the ruling faction. Next to his professional duties Idserts worked as a tile painter and developed himself into an inspired draughtsman. He’s generally considered as the first Frisian topographical artist of the eighteenth century. His qualities as a draughtsmen soon got recognized, which yielded him a function as a landscape artist at the Franeker highschool in 1744. From this time on the artist undertook trips through Friesland and Holland (up to Wateringen in the Westland), of which he makes accurate documentation in his sketchbooks. The sea coasts and river estuaries show a thorough knowledge of navigation and maritime history. Idsert’s drawings are often associated with the work of Gerrit Groenewegen (1754-1827).

On a richly staffed IJ, a merchant vessel with a man-o-war at his right are prominently depicted. Next to some inland vessels a yacht, which was in use for transport by wealthy merchants and governors. In the south-western distance the silhouette of Amsterdam is clearly distinguishable. In the central part of the composition is the lighthouse ‘Hoek van ‘t IJ‘ situated. The landmark was built on an especially applied island during 1701-02. The square stone tower was identical to the two other Suyderseese Vuurbakens in Marken and at De Ven. The lighthouse had been designed to house a powerful coal-burning system, which was never executed due to the high costs. From the beginning the tower was equipped with an oil-lamp. The present drawing clearly shows the lantern with its pointy cap. This lantern was replaced in 1832 by a more modern lantern with a walmbol.

Together with the construction of a new defensive work for the Defence Line of Amsterdam in 1893, the stone lighthouse was put down and at the south-side of the island arose the current cast iron lighthouse.