Reactions Involved in Black & White Photography

Black and white photography is often mesmerizing

Black and white photography existed before color photography. Even today, black and white photographs are widely used due to the powerful and effective emotions they evoke. This captivating form of photography is the result of several chemical reactions.

The Chemistry

Black and white photography is detailed and reacts differently than color.

Black and white photography brings out details and contrast. The way black and white photographs are created depends on the exposure of light sensitive material which forms the image, in terms of film photography. It starts with silver halides which is the light sensitive material, known as AgBr. AgBr is exposed to form the image depending on the frequency of light which is involved in this process. After being exposed to light, the AgBr forms an image on the film. When developing the image, the exposed AgBr grains convert to visible metallic deposit using an oxidized reducing agent, sodium sulphate.

Explanation

Black and white wedding photographs are classic and nostalgic

In plain terms, in black and white photography, acid-base reactions occur. Light reacts with silver halide crystals to form an image. Electrons are kicked out when the photon energy from the light excites particles. This happens while in contact with the emulsion on the paper. A developing solution magnifies this reaction when the paper is placed in it . As a result, the silver sticks together and darkens in some places, forming the image. This has to be done in a dark room since previously exposed paper will turn all black.

History

Documenting events, people or animals is ideally achieved through B&W photography

Black and white photography has a colorful history due to it being the firm form of photography used centuries ago by photographers such as Daguerre who formed plates with his first black and white photographs. Photographers have often used black and white photography to get a message across, whether it was of suffering, poverty, disaster, love or a significant event. These types of photographs often fall into the category of documentary photography or photojournalism. Many black and white photographers were successful in receiving positive reactions resulting in a movement, new law or basic change.

Tips

A camera is just the bridge between the imagination and the black and white image

You can take black and white photographs using a black and white setting on your digital camera, or using a film camera with black and white film. The developing process for black and white photographs is easier than for color, yet nowadays it is less common. Another option is to take photographs in color and then edit them on the computer by de-saturating the color, or simply converting them to black and white. This can be done through many computer art programs including Photoshop, Preview, iPhoto and Paint Shop Pro.

References

• University of Virginia Physics Department: An Acid-Base Reaction in Photography
• Sewanee: Photography