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التحكم المحلي في كثافة الطباعة .. المعالجة والطباعة بالأبيض والأسود .. المرشد خطوة بخطوة للتصوير الفوتوغرافي
Local control of print density
You will often find that , although you have given your print the correct overall exposure , some areas of the picture are slightly too dark or too light so that information on the negative is lost . You can control the local print density by reducing exposure time for parts you want lighter ( " shading " or " dodg- ing " ) , or increasing it for areas you want to be darker ( " printing - in " ) . To lighten an area , use your hand or a piece of black card to shade this part of the paper for several seconds during the main exposure To make an first give the overall ex- posure then , with a hole in a card or cupped hands , give extra exposure to the selected area only .
Working out the exposures
With experience you will soon be able to guess the number of seconds needed to shade or print- in . But to begin with , refer to your test strip , or make one specifically for this purpose .
On the print with 5 seconds exposure , below left , the back- ground figure has detail , but everything else is too light . At 20 seconds , below right , the detail is clear in the foreground figure and the rest of the picture , but the background figure has lost detail and is now much too dark .
From this you can see that the background figure should be shaded ( given less exposure ) and the remainder of the picture printed- in ( given more exposure ) . The bottom picture shows the final print , after shading and printing- in ; it contains all the information that was present in the 5 and 20 seconds prints , without any loss of detail . During one 20 second exposure , the background figure was shaded for the first 5 seconds ; then the whole image was ex- posed for a further 5 seconds , and finally the foreground figure and the highlight areas were printed- in for 10 seconds .
Shading . Cast a shadow with your hand over the relevant areal of the picture during part of the exposure . Keep your hand well above the paper , and continually moving , to soften its outline .
Dodging . A more localized form of shading can be done by making a small " dodger " with a piece of black card and wire .
Printing - in . After the main exposure use your hands to form a hole , or a piece of card with a hole in it , to give extra time to areas which printed too light . Blur the outline of the darkened area by moving your hands or the card .
Local control of print density
You will often find that , although you have given your print the correct overall exposure , some areas of the picture are slightly too dark or too light so that information on the negative is lost . You can control the local print density by reducing exposure time for parts you want lighter ( " shading " or " dodg- ing " ) , or increasing it for areas you want to be darker ( " printing - in " ) . To lighten an area , use your hand or a piece of black card to shade this part of the paper for several seconds during the main exposure To make an first give the overall ex- posure then , with a hole in a card or cupped hands , give extra exposure to the selected area only .
Working out the exposures
With experience you will soon be able to guess the number of seconds needed to shade or print- in . But to begin with , refer to your test strip , or make one specifically for this purpose .
On the print with 5 seconds exposure , below left , the back- ground figure has detail , but everything else is too light . At 20 seconds , below right , the detail is clear in the foreground figure and the rest of the picture , but the background figure has lost detail and is now much too dark .
From this you can see that the background figure should be shaded ( given less exposure ) and the remainder of the picture printed- in ( given more exposure ) . The bottom picture shows the final print , after shading and printing- in ; it contains all the information that was present in the 5 and 20 seconds prints , without any loss of detail . During one 20 second exposure , the background figure was shaded for the first 5 seconds ; then the whole image was ex- posed for a further 5 seconds , and finally the foreground figure and the highlight areas were printed- in for 10 seconds .
Shading . Cast a shadow with your hand over the relevant areal of the picture during part of the exposure . Keep your hand well above the paper , and continually moving , to soften its outline .
Dodging . A more localized form of shading can be done by making a small " dodger " with a piece of black card and wire .
Printing - in . After the main exposure use your hands to form a hole , or a piece of card with a hole in it , to give extra time to areas which printed too light . Blur the outline of the darkened area by moving your hands or the card .
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