Going with grain

Often said to be a limitation of high-speed film and something to be avoided, grain can nonetheless be used to good effect in fine-art photography. Photography Middle East correspondent Binu Bhaskar demonstrates.

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By  Kieran Potts Published  August 29, 2002

Introduction|~||~||~|A grainy effect is achieved by various techniques. Some filters are used to fragment the light reaching the film (try stretching a stocking over the lens), while 'texture' tools in software programmes like Adobe Photoshop mimic the same effects. Alternatively, the photograph can be printed on hard grade paper (such as grade IV). The traditional method, however, is to use high-speed film.

A photograph is composed of a series of coloured dots. In digital imaging, these pixels are captured by an electronic sensor, while on film they are created by a layer of light-sensitive particles that undergo a chemical reaction when exposed to light. These particles are clusters of silver halides, but different films arrange the film emulsion in different ways. For instance, film that is highly light sensitive - the sort used in dull conditions (ISO 400+) - groups the silver halide particles in large clusters to produce a wide surface area to capture the light. Slow films - used in daylight (ISO 25-400) - are composed of smaller clusters with a smaller surface area (so they are less light-sensitive).

It follows that films with fast ISO ratings have a coarser structure and so the grain is more noticeable in the final image. Slow films still have grain but it is so small that it is invisible to the naked eye.

Grain also becomes more evident when a photograph is increased in size, so commercial photographers prefer films of ISO 50, or even 25, and use large format film to reduce the necessity of enlargement. It is because so many photographers strive for the 'perfect' image that films of ISO 100-400 are the most popular. Film manufacturers spend considerable effort researching how to make films faster without losing resolution and, as a result, today many rolls of ISO 400 and 800 produce hardly any grain.

Yet, although millions of dollars are spent trying to get rid of it, grain is a powerful element in a photograph when used creatively. In colour it adds atmosphere and an impressionistic painterly effect, and in black and white creates mood and a stark gritty tone. Grain is to be exploited, my friend, not avoided.

ISO 1000 and above is recommended. Our favourite high-speed colour slide films are Fujichrome Provia 1600 and Kodak Ektachrome P1600; for prints we use Agfa XRS1000 and Konica SRG3200, and many professionals use Kodak Ektapress 1600. Ilford Delta is the first name that comes to mind for black and white, although Kodak T-Max 3200 and Fuji Neopan 1600 are justifiably popular choices. There are many others out there, and the best advice we can give is: try them all.

Uprating is a technique that enhances the grainy effect further. There is an encoding on most films that tells the camera what ISO it is, and the setting can be manually overridden to fool the camera into thinking that the film has a different ISO. So, if you insert 1600 film, then manually 'uprate' the camera's setting to 3200, in automatic mode the camera would underexpose the image (by one stop, in fact, as ISO 3200 film is twice as fast as ISO 1600). To print the photograph correctly, the negative would be 'pushed' in development (overexposed), again by one stop to achieve correct exposure. The over-development boosts grain size and contrast.

Uprating should be undertaken with soft diffuse lighting. Push-processing increases contrast, so high-contrast scenes (bright sunlight and shadows) will be captured with muddy grey tones or washed-out highlights. Neither does colour negative film respond well to push-processing, so it is best to use monochrome or colour transparency.

Grain can be added to a photograph in the development and printing stages. Edge-enhancing developer chemicals, such as Agfa Rodinal or Ultrafin, produce gritty results as they are intended to increase picture sharpness. Alternatively, the film can be placed in diluted print developer, which has a quick reaction to produce a clotted effect.

During the printing stage the easiest way to increase grain is simply to enlarge the image size. The texture of a 10x8" print will be more noticeable at 16x12". You could frame the subject only in the printing stage, leaving plenty of room for cropping when composing the scene through the lens, later selecting only part of the photograph for enlargement.

Finally, printing papers vary in coarseness, indicated by its grade number. Indeed, different papers vary in their reproduction of colour and contrast, and can therefore be selected according to the nature of the effect desired.

Grain can be added by simply taking a second photograph of the original photograph. An image shot on slow film could be photographed again with ultra-fast film; ideally the original would be a slide so it could be projected onto a large screen (you re-photograph the projected image). This technique is used to add grain while maintaining the bright vivid colours lost to high-speed film.

Zoom slide duplicators, which attach to your camera like a standard interchangeable lens, can also be used to create copies of a whole or partial slide. The transparency is placed at the far end of the duplicator lens. They are expensive, but useful for keeping copies of your work.

Alternatively, ask your processing lab if they can make a duplicate of your 35mm slide in 6x9cm format. The grain in the original shot will be more noticeable in the enlarged duplicate.

The benefits of adding grain with computer software are twofold. Firstly, the original picture does not have to be taken with high-speed film, and, secondly, you are in complete control over the degree of distortion you give to the picture.

Adobe Photoshop has several tools that will superimpose a grainy texture: the 'add noise' function has three modes (uniform, gaussian and monochrome), while the 'textures' menu has its own dedicated 'grain' option. The intensity of each filter is set by a number, usually 1-100. Experiment with a combination of tools to find the desired effect. The filters tend to work differently depending on the image's resolution, so try 72 dots per inch as well as higher resolutions for printing (300dpi). Other tools, such as toning, can be used simultaneously to compliment texture.
Remember that noise can get out of control when digitally editing photographs. Large expanses of single tones and colours get noise quickly when a sharpening filter is applied, so never sharpen plain skies or out of focus areas.
Some digital cameras will produce their own noise when the sensitivity of their sensor is set at a high ISO rating, or texture can be added during the scanning stage if you are using print film.

Finally, a grain effect can be achieved by printing a low resolution file (such as 150dpi) at high resolution (300dpi). However, this often produces washed out images. Unlike conventional photography, where the silver halide clusters themselves are enlarged, pixels in a stretched digital image will remain the same size and simply dissolve over a wider area of paper. So, unless this is a desired effect, avoid it.

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