One of the things I like best about black and white photography is the amount of drama that can be created with the tonal range from pure white to the deepest black.
There seems to be a lot of differing opinions on how many shades of gray the human eye can actually detect.
The human eye is capable of detecting around 10 million unique colours.
But it is only able to detect 30 shades of grey depending on the lighting.
Our eyes are unable to distinguish many shades on computer screens.
Some textbooks suggest humans can see between 8 and 450 grey shades.
Of course, that’s a rough estimate. Depending on the lighting conditions, surface texture, and background color, people may be able to distinguish a few more or a few less shades. Note that the image at the top of this story is an optical illusion, in which the bar is actually one shade of gray. The graded background makes the bar appear to have different shades along its horizontal axis.
In traditional silver based photography, black, white and shades of gray are all determined by the amount of light falling on the silver nitrate particles suspended in the media, be it film, egg whites or other substance which holds the particles. Light hitting the silver turns the particles dark when processed. The lightest areas of the picture are shown in reverse – they are dark on the negative. This process is reversed when the film is used to expose a sheet of photo sensitive paper in the darkroom. The negative holds pack the light areas and lets light pass through the dark areas. This reverses the image back from a negative into a positive. The lightest areas show the paper substrate white the exposed silver nitrate particles turn various shades of gray in the development chemical baths.
Darkroom photographers manipulate the areas of light and dark to using the techniques of dodging and burning. Dodging is using ones hands or pieces of paper to restrict the amount of light hitting the paper in a certain area. Burning is giving a certain area more exposure or more light to darken that area.
The same tools are available in the modern digital darkroom. In Adobe Photoshop and other software programs one an brush on more light or more darkness to certain areas of the image. Or create sophisticated layer masks to control the amount of light needed to achieve the artist’s vision.
Dodging and burning can be used on color photographs also but it can become more complex because you have to be careful not to change the color tones and result with something unnatural looking.
This still life photograph by Edward M. Fielding was shot with some strategically dramatic studio lighting but the effects were enhanced in post production using dodging and burning. The highlights were lighted and shadows deepened to bring about a dramatic effect.
The white fur on this West Highlands White Terrier kept burning out and losing detail under the studio lights. Burning was used to tone down the white highlights and bring back detail to the fur.
The complex lighting on this still life of an old antique pocket watch was enhance with dodging and burning techniques for a dramatic result.