Rembrandt van Rijn | Woman with a Pink, early 1660

Her forehead crisscrossed with jewels, the sitter of this portrait displays a pink, or carnation, a symbol of love and marriage.

The gilt picture frame visible in the background locates her in a luxurious interior, but her pensive expression elevates the portrait beyond a mere statement of status.

If scholars are correct in identifying the sitter in the pendant portrait hanging next to this one as auctioneer Pieter Haringh, then the woman who appears here must be his wife, Elisabeth Delft. | Source: © Metropolitan Museum of Art

Rembrandt | Woman with a Pink, early 1660s | Metropolitan Museum of Art

Beethoven | Heiligenstadt Testament, 1802

Il Testamento di Heiligenstadt è una lettera manoscritta del musicista tedesco Ludwig van Beethoven (1770-1827) indirizzata ai suoi fratelli Kaspar Karl e Nikolaus Johann, scritta il 6 ottobre 1802 a Heiligenstadt, un sobborgo di Vienna, dove il compositore aveva la residenza.

A soli 32 anni, Beethoven intuisce che la sua sordità sarà irreversibile.

I primi sintomi erano stati già individuati dal grande compositore tedesco nel 1796, cioè a 26 anni.

Joseph Karl Stieler | Beethoven with the Manuscript of the Missa Solemnis, 1820

Rembrandt's 'recipe for a stopping-out varnish'

Rembrandt's 'recipe for a stopping-out varnish' on the verso of a drawing 'Landcape with a River and Trees', 1654-55.

• "..in order to etch, take white turpentine oil, and add half the turpentine to it; pour the mixture into a small glass bottle and let it boil in pure water for half an hour".

It is evident that Rembrandt refers (alas fragmentarily) to a so-called 'stopping-out varnish', used to terminate the bite of acid in select areas of a plate that had already been exposed to the etching agent.

Thus other portions will remain exposed to the acid to deepen the bite.

Seven Colours of the Rainbow

A rainbow is an optical phenomenon caused by refraction, internal reflection and dispersion of light in water droplets resulting in a continuous spectrum of light appearing in the sky.

The rainbow takes the form of a multicoloured circular arc.

Rainbows caused by sunlight always appear in the section of sky directly opposite the Sun.

Rainbows can be caused by many forms of airborne water.

These include not only rain, but also mist, spray, and airborne dew.

Jean-Léon Gérôme | La République, 1848 | Musée des Beaux-Arts de la Ville de Paris, Petit Palais

Eastman Johnson | Co-founder of the Metropolitan Museum of Art

Eastman Johnson (1824-1906) was an American painter and Co-Founder of the Metropolitan Museum of Art, New York City, with his name inscribed at its entrance.

Best known for his Genre paintings, paintings of scenes from everyday life, and his portraits both of everyday people, he also painted portraits of prominent Americans such as Abraham Lincoln, Nathaniel Hawthorne, Ralph Waldo Emerson and Henry Wadsworth Longfellow.

His later works often show the influence of the 17th-century Dutch masters whom he studied while living in The Hague, and he was even known as The American Rembrandt in his day.