CAMERA OBSCURA

In the previous post, I mentioned that Canaletto often used a camera obscura as an aid to creating his drawings and paintings.  Let's discuss what that is...

The principle of the camera obscura has been known since ancient Greek and Chinese time, but it became popular during the Renaissance of the 1500s.  The literal translation of the Latin term is dark room (camera for "room", obscura for "dark").

It works like this:  You are in a very dark room on a very sunny day.  Cut a small hole in a window cover and look at the opposite wall.  What do you see?  Magic! There in full color will be a view of outside the window upside down! This magic is explained by a simple law of the physical world.  Light travels in a straight line and when some of the rays reflected from a bright subject pass through a small hole in thin material they do not scatter but form an upside down image on a flat surface parallel to the hole.  With mirrors positioned inside the room the image could be flipped 180 degrees and reflected right-size-up onto a surface for tracing onto a canvas.

In the image above you can see how an artist would use the camera obscura to help create his painting.  The reflected image inside the camera obscura not only miniaturizes the scene reflected, but it also intensifies color, and highlights and increases the contrast of light and dark areas.  The image could then be traced to create an accurate sketch and be transformed into a painting.  

In the mid-17th century the portable camera obscura was developed and became the basis of the photographic camera.