essential skills: photographic lighting
Choosing a capture medium There has been a shift towards digital image capture in recent years as it has the advantage of producing an image almost immediately (no processing required). It creates image files, downloaded to a computer, suitable for desktop publishing. A limiting factor has been the expense of digital cameras capable of providing the quality suitable for large commercial illustration. Until recently commercial photography reproduced in magazines has traditionally and almost exclusively been produced using positive or reversal (transparency) film. The advantage of reversal over negative film has been that it is a one-step process to achieve a positive image. However, advances in digital capture are replacing film capture in most commercial situations. A negative film emulsion (still used extensively in the film industry) will give you, within its limitations, an image opposite to that seen through the viewfinder. It is only when a negative is printed that it becomes a positive image. The advantage of negative film is its greater ‘latitude’ and ability to handle higher subject contrast levels than positive film.
Image processing Digital image processing is carried out on a computer platform. The commercial illustration industry favors Apple Macintosh computers and the software ‘Adobe Photoshop’. Color transparency film is processed using the E-6 process. This is a Kodak processing system and will process nearly all color positive films. Color negative film is processed using the C-41 process. This is also a Kodak processing system and will process nearly all color negative films. Color film processing should be undertaken by a professional laboratory. Although it is currently possible to purchase chemicals to process color film the money saved may well be a false economy when considering the experience and equipment required to produce consistent and accurate color processing. The number of black and white processing systems are as varied as the number of films available. Although not covered in this book it is recommended all photographers develop a thorough understanding of black and white processing. It is relatively simple technology (it has changed little since its introduction) and easy to learn.
Appropriate exposure Assessing correct image exposure can be achieved by viewing the film on a light box or by examining a histogram of the digital image file. It takes practice to be precise about the subtleties of underexposure and overexposure but there is a simple starting point. If there is no image detail something is wrong. If, when viewing a digital image, a large peak is apparent at one or both ends of the histogram then detail may be missing through excessive contrast or poor exposure. If negative film appears ‘dense’ (transmits very little light) with no visible detail it is probably overexposed. If positive film appears ‘dense’ it is probably underexposed. If negative film appears ‘thin’ (transmits nearly all light) with no visible detail it is probably underexposed. If positive film appears ‘thin’ it is probably overexposed.
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