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ملخص معالجة الألوان والطباعة .. المرشد خطوة بخطوة للتصوير الفوتوغرافي
SUMMARY Color processing and printing
Color processing
Compared with black and white pro- cessing , color film processing has more stages , and uses higher temperatures . It also requires a stricter control of time , temperature , and agitation . You will not need much more equipment than you used for black and white processing , but color chemicals are more expensive and must suit your particular brand of film .
Color printing : filtering methods
Color printing uses either the additive or subtractive filtering methods . Subtractive printing requires more filters ; but additive printing takes more time and calculation , and local adjustments are more difficult .
For both methods you require ultra - violet and infra - red filters .
Color printing : procedure
Always make two test strips the first for exposure , the second for filtration .
Try to avoid exposures exceeding 10-15 seconds , and make sure you eliminate neutral density from your filter pack .
Alter the filtration when changing your paper batch , replacing the enlarger lamp , changing to a negative of a different brand , or using an image taken under different color temperature lighting .
Printing slides
To print direct from slides you require reversal color printing material . This may use dye destruction or chemically formed dyes . All the normal filtering and exposure techniques work in reverse .
Reversal print materials have more ex- posure latitude , but require larger filter value changes than normal color printing papers . Dye - destruction print material has some special advantages - fewer pro- cessing stages , lower processing tem- peratures , and wide tolerances . It also produces richer , more fade - resistant colors .
Color printing faults
Most faults are traceable to the chemical side of processing and printing - con- tamination , exhaustion of solutions , and uneven action .
When tracing faults look at the negative first , comparing it against a negative which is known to print well . If the fault is not in the negative then it must have resulted in printing or print processing .
You can spot and locally dye color prints . but do not knife out blemishes . Some limited overall correction of color casts is possible with slides by using selective bleaching solutions .
SUMMARY Color processing and printing
Color processing
Compared with black and white pro- cessing , color film processing has more stages , and uses higher temperatures . It also requires a stricter control of time , temperature , and agitation . You will not need much more equipment than you used for black and white processing , but color chemicals are more expensive and must suit your particular brand of film .
Color printing : filtering methods
Color printing uses either the additive or subtractive filtering methods . Subtractive printing requires more filters ; but additive printing takes more time and calculation , and local adjustments are more difficult .
For both methods you require ultra - violet and infra - red filters .
Color printing : procedure
Always make two test strips the first for exposure , the second for filtration .
Try to avoid exposures exceeding 10-15 seconds , and make sure you eliminate neutral density from your filter pack .
Alter the filtration when changing your paper batch , replacing the enlarger lamp , changing to a negative of a different brand , or using an image taken under different color temperature lighting .
Printing slides
To print direct from slides you require reversal color printing material . This may use dye destruction or chemically formed dyes . All the normal filtering and exposure techniques work in reverse .
Reversal print materials have more ex- posure latitude , but require larger filter value changes than normal color printing papers . Dye - destruction print material has some special advantages - fewer pro- cessing stages , lower processing tem- peratures , and wide tolerances . It also produces richer , more fade - resistant colors .
Color printing faults
Most faults are traceable to the chemical side of processing and printing - con- tamination , exhaustion of solutions , and uneven action .
When tracing faults look at the negative first , comparing it against a negative which is known to print well . If the fault is not in the negative then it must have resulted in printing or print processing .
You can spot and locally dye color prints . but do not knife out blemishes . Some limited overall correction of color casts is possible with slides by using selective bleaching solutions .
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