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The zone system
The zone system was devised by the Ameri- can photographer , Ansel Adams , as an aid to calculating the required exposure for a particular range of tones . It divides the tone scale into separate zones , numbered 0-9 . A reflected light exposure reading taken from a gray card , or its equivalent within the subject , will record that area in the tone of zone 5. Increasing or decreasing exposure by one f stop will move the tone reproduction throughout the picture by one zone , up or down the scale . Remembering this you can adjust the exposure to make any subject tone you choose record as zone 5 .
The zone system is based on a Weston hand meter , and requires strict control of development and enlarging conditions . How- ever , it is a system you can apply generally to hand and camera meter readings .
The zone scale
The subject above reflected a wide range of tones . Using one gray card reading they reproduced as values on the scale , above left .
This general reproduction of detail is suitable for most subjects . Meter readings are designed to give this sort of result . But some- times you may want to reduce shadow detail in the image , by reducing the exposure , or reduce highlight detail , by increasing the exposure . Increasing exposure
by one stop shifts all the tones in the picture along the scale by one value . Subject areas 4 and 5 will be interpreted as zones 5 and 6 and so on , showing more detail in the shadows , less in highlights . The reverse happens when ex- posure is reduced .
To use the zone system you must standardize your processing and printing , following the procedure that will reproduce the full zone range from a subject with a wide range of tones .
Gray card reading
Taking readings from a gray card , as shown right , will maintain a constant mid - gray in all your pic- tures . Measure the reading off the card under subject lighting condi- tions . " Mid - gray " card is . sold by Kodak , but any suitable mat sur- face card reflecting 18 per cent of incident light is suitable .
Selecting zones
The essence of the zone system is to " place " one tone value by careful exposure measurement , then if necessary control where other tones fall by altering development . The picture below right shows the result of giving an overall reading and normal development . The girl's shadowed face has repro- duced as about zone 2 on the zone scale . so all detail is lost . In the picture below left the meter reading was taken from close to the face . This showed that three f stops more exposure was needed , reproducing the face as zone 5. The lighter back- ground is now mostly zone 8 and " burned out " . Detail here can be improved by giving the negative less development ( p . 127 ) which compresses the whole tone scale . This would restore the background to about zone 7 or 6 .
The zone system
The zone system was devised by the Ameri- can photographer , Ansel Adams , as an aid to calculating the required exposure for a particular range of tones . It divides the tone scale into separate zones , numbered 0-9 . A reflected light exposure reading taken from a gray card , or its equivalent within the subject , will record that area in the tone of zone 5. Increasing or decreasing exposure by one f stop will move the tone reproduction throughout the picture by one zone , up or down the scale . Remembering this you can adjust the exposure to make any subject tone you choose record as zone 5 .
The zone system is based on a Weston hand meter , and requires strict control of development and enlarging conditions . How- ever , it is a system you can apply generally to hand and camera meter readings .
The zone scale
The subject above reflected a wide range of tones . Using one gray card reading they reproduced as values on the scale , above left .
This general reproduction of detail is suitable for most subjects . Meter readings are designed to give this sort of result . But some- times you may want to reduce shadow detail in the image , by reducing the exposure , or reduce highlight detail , by increasing the exposure . Increasing exposure
by one stop shifts all the tones in the picture along the scale by one value . Subject areas 4 and 5 will be interpreted as zones 5 and 6 and so on , showing more detail in the shadows , less in highlights . The reverse happens when ex- posure is reduced .
To use the zone system you must standardize your processing and printing , following the procedure that will reproduce the full zone range from a subject with a wide range of tones .
Gray card reading
Taking readings from a gray card , as shown right , will maintain a constant mid - gray in all your pic- tures . Measure the reading off the card under subject lighting condi- tions . " Mid - gray " card is . sold by Kodak , but any suitable mat sur- face card reflecting 18 per cent of incident light is suitable .
Selecting zones
The essence of the zone system is to " place " one tone value by careful exposure measurement , then if necessary control where other tones fall by altering development . The picture below right shows the result of giving an overall reading and normal development . The girl's shadowed face has repro- duced as about zone 2 on the zone scale . so all detail is lost . In the picture below left the meter reading was taken from close to the face . This showed that three f stops more exposure was needed , reproducing the face as zone 5. The lighter back- ground is now mostly zone 8 and " burned out " . Detail here can be improved by giving the negative less development ( p . 127 ) which compresses the whole tone scale . This would restore the background to about zone 7 or 6 .
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