Walnut oil for painting, with mechanisms and pen-trials
A note on why unstripped walnuts spoil painting oil, above gear and screw devices and a letter draft
The sheet is crowded with small mechanical studies — ratchet wheels with pawls, cranks, a screw-driven hook and a windlass at the lower left — interspersed with pen-trials and a draft letter that repeats names such as Francesco d'Antonio and Bernardo di Maestro Iacopo. A paragraph at the top explains why walnut oil turns the surface of a painting: if the walnuts are not stripped of the thin skin of their husk before the oil is made, the husk stains the oil and later rises to the picture's surface. A hook-pin fixed by a screw and a pivot ('bilico') are labelled, and a small coat of arms is drawn at the upper right corner.
On this page
Why walnut oil changes a painting's surface
The top note explains that walnuts are wrapped in a thin skin sharing the nature of the husk; if they are not stripped when the oil is made, that husk stains the oil, then separates and rises to the surface of the painting, and this is what makes the picture change.
Screw-hook, pivot and ratchet-wheel fittings
A hook-pin driven in by a screw is labelled, and elsewhere a pivot ('bilico') is named. The sheet is filled with ratchet wheels with pawls, cranks and a windlass; the Ambrosiana index notes wheels with ratchet teeth and a detent.
Draft letter and repeated names
A draft on the right repeats 'As I told you in days past, you know that I am without any of the friends' and phrases about 'your affairs' and 'the winter', interspersed with the names Francesco d'Antonio and Bernardo di Maestro Iacopo written and rewritten.
Small coat of arms
A shield bearing a heraldic device is sketched in the upper right corner of the sheet, and an ornamental flourish accompanies the fragment 'di' lower down. Neither is explained in the transcribed notes.