on the Sportello thread

[David Morris]

http://www.koopfilms.com/hockney/intro.html

http://www.koopfilms.com/hockney/articles.html

The Hockney-Falco thesis

In the 2001 television programme and book, Secret Knowledge, Hockney
posited that the Old Masters used camera obscura techniques, utilized
with a concave mirror, which allowed the subject to be projected onto
the surface of the painting. Hockney argues that this technique
migrated gradually to Italy and most of Europe, and is the reason for
the photographic style of painting we see in the Renaissance and later
periods of art. This theory has been opposed by the Art Renewal Center
who have published several articles attempting to disprove "Secret
Knowledge" by means of historical documents and the experiences of
living artists who do not use any photography yet have produced
photorealistic drawings and paintings.


http://www.makart.com/resources/artclass/finder.html

PERSPECTIVE MACHINE
String a grid in a frame, (preferred is a grid dividing the frame into
thirds or a multiple of three, and a frame in golden proportion or the
same proportion as your paper), fix it in place between you and your
subject, as shown in Durer's etching. Use it along with a similar grid
on your paper to aid in producing an accurate layout of your subject
matter. Note that the relationship between your eye, the frame and the
subject must remain constant. Useful when dealing with foreshortening
or when accuracy of proportion is important to the layout.