Episode 29 - Unwanted Material

Part 1: Surface Cleaning

Anny Aviram, longtime painting conservator at the Museum of Modern Art, New York, dusting The Dream by Henri Rousseau. Click image for video.

Making a swab with a bamboo skewer and cotton wool

Surface cleaning with saliva on cotton swabs removing soot and grime

Cleaned area (right side of shoulder) looks more saturated

Surface cleaning with saliva on cotton swabs removing tobacco smoke residue

Dry cleaning the reverse of a painting with a brush and dry cleaning sponges

The dirty reverse of a painting before and after removing the canvas from the stretcher: dirt, mold, insect cocoons

The dirty reverse of a painting before and after removing the canvas from the stretcher: water stains and dried mud

Gecko found between canvas and stretcher bar of a painting

Part 2: Varnish Removal

John Brealey, during the restoration of Las Meninas by Diego Velázquez in 1984.

Paco Junquera (Cover/Getty Images)

Raphael, The Colonna Altarpiece, c 1504

Parts from different collections reunited for

Raphael: Sublime Poetry, Metropolitan Museum of Art, March 29 - June 28, 2026

The Agony in the Garden, The Metropolitan Museum of Art and The Procession to Calvary, National Gallery, London

While the skies in these two paintings would have originally been exactly the same color, the Met painting now looks slightly yellower; the difference is likely caused by differences in varnish.

The Procession to Calvary, National Gallery, London and Pietà, Isabella Stewart Gardner Museum, Boston

Here, too, there is a difference in tonality.