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الخطوة 4: الطباعة المتلاعب بها / التحكم في التباين .. المعالجة والطباعة بالأبيض والأسود .. المرشد خطوة بخطوة للتصوير الفوتوغرافي
STEP 4 : MANIPULATED PRINTING / Contrast control
- You have already seen how to compensate for overall darkness or lightness of a negative by varying the printing either giving longer or shorter exposure times , or adjust- ing the enlarging lens aperture . But you may also want to alter the contrast on the print , that is the range and gradation of gray tones , and you can do this by using papers of different contrast grades .
The negative shown enlarged on page 81 was printed on normal grade paper , but photographic paper can also be bought in soft and hard grades . Soft grade papers will produce far more gray tones between black and white than hard grades . ( Although not shown here , extra soft and extra hard grades are also available in some popular printing papers , giving up to five grades in all . ) You can see the effects on contrast of printing a normal contrast negative on soft , normal , and hard papers across the middle row .
This ability to control contrast becomes really useful when you are printing a low contrast negative like the statue of the lion , top , or a high contrast negative like that of the building , below . As you can see , the flatter , or lower in contrast , the negative , the harder the grade of paper needed to compensate and give a normal contrast print .
If you are a beginner at enlarging and unsure about judging negative contrast by sight , first make a test strip followed by the best possible complete print , on normal grade paper . Then you can decide whether an increase or decrease in overall contrast would help the picture . Later you will be able to decide this direct from the test strip , but when you are beginning it is difficult to assess the overall print contrast from the narrow exposure bands . When changing from one grade to another , remember that some brands of bromide paper require slight adjustment of exposure time , so that you may have to make a new test strip . Generally , the harder paper grades need longer exposures than normal or soft grades .
Variable contrast papers
Instead of having to buy a stock of papers in each grade , you can use a variable contrast paper , such as Kodak Polycontrast . This alters the contrast it gives according to the color of the printing light used ( the process is explained on page 87 ) . Without a filter the paper gives relatively normal contrast ; a pale yellow filter converts it to soft con- trast , and a bluish filter changes it to hard . A range of seven filters is available , allow- ing you to make gradual changes . They are made in two types : acetate , which fit in the enlarger filter drawer , or gelatin or glass , for use below the lens . Again , some adjust- ment of exposure time is needed when changing filters . Variable contrast papers are more sensitive to yellow light so you may need a darker , more amber safelight .
Assessing negative contrast
To assess the contrast on the negative , look at the range of grays between the darkest and lightest important parts of the image . ( Compare this against the sort of tonal range you have dis- covered will print well on normal grade paper on your enlarger . ) Don't be misled by overall density - very dense ( dark ) or very thin ( pale ) negatives are often rather flat in contrast . Contrasty neg atives will appear " bright " and have bold tone differences ; flat negatives look gray .
Low contrast negative
A flat , or low contrast negative . due to overcast lighting , hazy conditions , or underdevelopment ( or a combination of these ) , will print best on hard grade paper , far right .
Normal contrast negative
A normal contrast negative prints well on normal grade paper . center . Notice the effects of print- ing on soft grade paper , near right , and hard grade , far right .
High contrast negative
The high contrast of a harsh . or " contrasty " negative could be caused by harsh side - lighting , or overdevelopment . Contrasty nega tives print most successfully on soft grade paper , near right .
Paper grades
Soft grade paper
Soft contrast photographic paper is usually rated by the manufac- turer as grade 1. or the even softer grade 0. It forms a large range of grays between black and white , which will counteract the harshness of a contrasty negative .
Normal grade paper
Normal grade paper is usually described as grade 2. It is designed to suit an average contrast nega- tive and normal enlarging con- ditions . Normal grade paper is suitable for average subject light- ing and development , but you may decide to use a harder or softer paper to suit the subject .
Hard grade paper
Photographic papers of grade 3 . or the more extreme grades 4 and 5. give a smaller number of grays between black and white than normal paper . They reduce and simplify the excessive grays in a low contrast negative , printing them as fewer and more separate tone differences .
A flat negative prints best on hard grade paper , near left .
A normal negative prints best on normal grade paper , center .
A contrasty negative . prints best on soft grade paper , far left .
STEP 4 : MANIPULATED PRINTING / Contrast control
- You have already seen how to compensate for overall darkness or lightness of a negative by varying the printing either giving longer or shorter exposure times , or adjust- ing the enlarging lens aperture . But you may also want to alter the contrast on the print , that is the range and gradation of gray tones , and you can do this by using papers of different contrast grades .
The negative shown enlarged on page 81 was printed on normal grade paper , but photographic paper can also be bought in soft and hard grades . Soft grade papers will produce far more gray tones between black and white than hard grades . ( Although not shown here , extra soft and extra hard grades are also available in some popular printing papers , giving up to five grades in all . ) You can see the effects on contrast of printing a normal contrast negative on soft , normal , and hard papers across the middle row .
This ability to control contrast becomes really useful when you are printing a low contrast negative like the statue of the lion , top , or a high contrast negative like that of the building , below . As you can see , the flatter , or lower in contrast , the negative , the harder the grade of paper needed to compensate and give a normal contrast print .
If you are a beginner at enlarging and unsure about judging negative contrast by sight , first make a test strip followed by the best possible complete print , on normal grade paper . Then you can decide whether an increase or decrease in overall contrast would help the picture . Later you will be able to decide this direct from the test strip , but when you are beginning it is difficult to assess the overall print contrast from the narrow exposure bands . When changing from one grade to another , remember that some brands of bromide paper require slight adjustment of exposure time , so that you may have to make a new test strip . Generally , the harder paper grades need longer exposures than normal or soft grades .
Variable contrast papers
Instead of having to buy a stock of papers in each grade , you can use a variable contrast paper , such as Kodak Polycontrast . This alters the contrast it gives according to the color of the printing light used ( the process is explained on page 87 ) . Without a filter the paper gives relatively normal contrast ; a pale yellow filter converts it to soft con- trast , and a bluish filter changes it to hard . A range of seven filters is available , allow- ing you to make gradual changes . They are made in two types : acetate , which fit in the enlarger filter drawer , or gelatin or glass , for use below the lens . Again , some adjust- ment of exposure time is needed when changing filters . Variable contrast papers are more sensitive to yellow light so you may need a darker , more amber safelight .
Assessing negative contrast
To assess the contrast on the negative , look at the range of grays between the darkest and lightest important parts of the image . ( Compare this against the sort of tonal range you have dis- covered will print well on normal grade paper on your enlarger . ) Don't be misled by overall density - very dense ( dark ) or very thin ( pale ) negatives are often rather flat in contrast . Contrasty neg atives will appear " bright " and have bold tone differences ; flat negatives look gray .
Low contrast negative
A flat , or low contrast negative . due to overcast lighting , hazy conditions , or underdevelopment ( or a combination of these ) , will print best on hard grade paper , far right .
Normal contrast negative
A normal contrast negative prints well on normal grade paper . center . Notice the effects of print- ing on soft grade paper , near right , and hard grade , far right .
High contrast negative
The high contrast of a harsh . or " contrasty " negative could be caused by harsh side - lighting , or overdevelopment . Contrasty nega tives print most successfully on soft grade paper , near right .
Paper grades
Soft grade paper
Soft contrast photographic paper is usually rated by the manufac- turer as grade 1. or the even softer grade 0. It forms a large range of grays between black and white , which will counteract the harshness of a contrasty negative .
Normal grade paper
Normal grade paper is usually described as grade 2. It is designed to suit an average contrast nega- tive and normal enlarging con- ditions . Normal grade paper is suitable for average subject light- ing and development , but you may decide to use a harder or softer paper to suit the subject .
Hard grade paper
Photographic papers of grade 3 . or the more extreme grades 4 and 5. give a smaller number of grays between black and white than normal paper . They reduce and simplify the excessive grays in a low contrast negative , printing them as fewer and more separate tone differences .
A flat negative prints best on hard grade paper , near left .
A normal negative prints best on normal grade paper , center .
A contrasty negative . prints best on soft grade paper , far left .
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