SINCE publication of the sixth edition a number of significant advances in photographic equipment, materials, and practices have been made. Cameras have become more sophisticated and the 110 format has been introduced. Special cameras for "instant-print" colour materials are becoming increasingly popular and two major manufacturers now produce separate systems for this type of photography. Resin coated papers have become available for black and white as well as colour printing together with appropriate processing equipment. The move to smaller format cameras has necessitated the introduction of a new generation of colour films and the processing and printing of colour materials has become simpler and quicker. These and other developments are included in the present edition. As editor of the new edition I have followed the example set by previous editors in directing the emphasis towards the principles underlying the practice of photography, although this edition still contains...