One of the best kept secrets amongst artists is the degree to which they rely on photos in doing their work. And here I'm not just talking about the occasional use of pictures from a "grab file" but photos from which most or all of the painting is rendered. Today, portrait artists are most open regarding their use of photos though still quite reticent usually in divulging just "how" they use them, and not without good reason. Most individuals commissioning a portrait consider photos a convenience as much as does the artist. After all, without them, both would be tortured by long, tedious settings from which only the best models and the best artist would emerge from the ordeal with great paintings. Beyond that though, artist make sure few people are aware if they use any kind of projection device to enhance speed and accuracy. Though most artists no longer feel "guilty" in this form of "cheating," some still continue to condemn it, especially when in the hands of the clumsy practitioner. In terms of the general public, an artist drawing from a projected image is still very much frowned upon. It seems to them to somehow destroy the mystical magic of "drawing."
It may come as a surprise to some, but a couple of the most admired artists in history seem to have relied almost totally on projected images in the drawing stages of their paintings. In the mid-1600s, Jan Vermeer was probably the first to actually USE such labor-saving methods as his sole means of drawing upon his canvases. But the device he used was not new by any means. The Italians had first experimented with it during the Renaissance. The "contraption" he used was a wooden framework set against a wall with a wooden top and dark curtains hung on the other three sides. The canvas was mounted on the wall, and a plank with a tiny, rectangular hole in it was mounted on the front of the frame to allow a small amount of light into the cubicle. The size of the hold determined the sharpness of the image while the depth of the cubical determined the SIZE of the resulting, projected image. The image, of course, came out upside down on the canvas, but that was of little consequence.
The device was called the camera obscura (dark chamber). One of the hallmarks of Vermeer's work included a wall of windows on the left in most of his paintings through which bright sunlight was admitted--a perequisite for using such a device. Holland being the world center at the time in the production of lenses, it's quite likely his camera obscura pioneered their use as well. A hundred years or so later, the Venetian artist, Canaletto used a similar device. Or more precisely, it's likely his assistants did. It takes no great artistic skill to use such a visual aid beyond some basic instruction and a little trial and error. The sheer QUANTITY of Caneletto's output alone would have dictated their use. Beyond that, the consistent QUALITY of his renderings of the Venetian cityscape gives further evidence of his reliance on such technology. Believe it or not, there was even handheld, portable camera obscura (a canoe-like contraption which fit over the artist's head and shoulders), for drawing on location. What can I say? Another art "secret" bites the dust.