For those of us who know how to draw and understand the varieties of linear perspective, David Hockney’s proposal that the old masters used optical aids rings true. One of his examples will suffice: The uncanny accuracy of difficult-to-depict patterns in folding cloth in works of the early 1400s is an indication that optical aids were used.

Edward Harvey
Allan Hancock College
Santa Maria, Calif

Concerning the question of optical aids, there is a possible answer well short of the use of lenses, mirrors, or a pinhole camera obscura. A simple grid of strings and a fixed eye point will allow the artist to create a correct perspective with the use of a corresponding grid on paper. There is evidence that Albrecht Dürer used this technique.

Peter Jones
Boston, Mass

The Impressionists insisted they wanted to paint directly what they saw in nature. The true revolt of these artists was against the use of mirror images to create art.

Mary Belle O’Brien
New York, N.Y

Stork’s analysis of the chandelier in “Portrait of Giovanni Arnolfini and His Wife” by Jan van Eyck rests on the axiom that its arms are precisely identical. It seems anachronistic to expect the 15th-century artisan who fabricated the chandelier to have bothered with this detail. And the argument neglects the possibilities of imprecise assembly, as well as wear and tear. In short, the chandelier itself might have given these results, even if photographically rendered.

Leandra Vicci
Silk Hope, N.C

David Stork says that he has superimposed lines on a photograph of a casting of a 15th-century chandelier from the town where van Eyck painted. The photo passes tests of symmetry that the painted chandelier fails, Stork says .–P. Weiss