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طباعة الاختبار .. المعالجة والطباعة .. كيفية التقاط وتطوير الصور بالأبيض والأسود
THE TEST PRINT
With the negative and contact sheet at hand , you are ready to select one frame for printing . Once you have chosen the negative , the cropping and the size of the enlargement , the next stage is to find the best overall exposure .
The processing stages are the same as for the contact sheet , except that some photographers like to vary the development time according to how the image comes up . To begin with , however , it is best to stick to a standard procedure : the fewer variables , the easier it is to make adjustments . In any case , prepare all the chemicals as shown on the previous pages .
MAKING A TEST PRINT
1. Prepare the developer , stop bath and fixer to the point of having an or- dered row of trays , all at the right temperature .
2. Take the negative strip , hold it by its edges , and place it , emulsion side down , in the enlarger's negative carrier .
3. Remove dust from the negative with a burst of compressed air or a soft anti - static brush . Hold it an angle under the enlarger's light for a close check .
ABOVE Choose from the negative the most important tones and try and cover these with each exposure .
BELOW A standard series of exposure times , from five to twenty seconds , gives a good indication of what the final exposure should be . From the examination of the negative , the central part of the picture with its range of skin tones is the most important , and the test bands were arranged so that the most likely exposure falls in this area . Twenty- second and fifteen - second exposures are too dark , with obvious loss of detail in shadow areas , while five seconds leaves the highlights white and featureless . The ten second exposure is almost right , but perhaps a little too dark .
Place the negative in the enlarger's negative carrier ( emulsion side down ) , cleaning off any dust with a blower , anti- static brush or anti - static gun .
Insert the carrier in the enlarger head . With the room lights out , the enlarger head on and the lens aperture wide open , adjust the enlarger head until the image is focused and the size you have chosen .
Adjust the focus until the image is critically sharp . This can be judged either by eye alone or with the use of a magnifier .
Close down the lens aperture about two stops ( normally this would be f11 ) . With negative of normal density , this will let you use reasonably short exposure times and the lens performance will be at its peak . Greater depth of field will also compensate for any focusing errors .
Under safelight illumination , and with the enlarger lamp off , insert a sheet of normal ( Grade 2 ) paper , emulsion side up , into the printing frame and set the timer to five seconds .
Hold a piece of black card over the sheet of paper , leaving just a quarter of its width exposed , and give a five - second exposure . Move the card along for a second exposure of five seconds . Make third and fourth exposures in the same way .
4. Place a sheet of plain white paper , such as the back of a discarded print , in the easel , and adjust the easel's masks to approximately the proportions that you want . This paper will make composition faster and focusing easier .
5. Turn the safelight on and the room light off . With the lens at full aperture , adjust the enlarger head so that the image fills the frame and is sharply focused .
6. Make final adjustments to the easel masks , as necessary .
7. Reduce the lens aperture by about two stops from fully open . On most lenses this gives the best optical performance .
8. Take a fresh sheet of printing paper and insert it in the easel , emulsion side up , replacing the plain white sheet .
9. Cover all of the exposed paper except for a narrow strip ( about 20 % of the area ) with a piece of thick , opaque card . Make a 5sec exposure .
10. Move the card to uncover a little more of the paper , and give another 5sec exposure . Continue this until all the paper has been exposed ( for the last exposure the sheet should be completely uncovered .
11. Process the paper as described earlier , for one minute in the developer , several seconds in the stop bath , and in the fixer for two minutes .
12. Wash and dry .
ABOVE The area within the dotted lines marks the most important range of contrasts in this image , from the printer's point of view .
THE TEST PRINT
With the negative and contact sheet at hand , you are ready to select one frame for printing . Once you have chosen the negative , the cropping and the size of the enlargement , the next stage is to find the best overall exposure .
The processing stages are the same as for the contact sheet , except that some photographers like to vary the development time according to how the image comes up . To begin with , however , it is best to stick to a standard procedure : the fewer variables , the easier it is to make adjustments . In any case , prepare all the chemicals as shown on the previous pages .
MAKING A TEST PRINT
1. Prepare the developer , stop bath and fixer to the point of having an or- dered row of trays , all at the right temperature .
2. Take the negative strip , hold it by its edges , and place it , emulsion side down , in the enlarger's negative carrier .
3. Remove dust from the negative with a burst of compressed air or a soft anti - static brush . Hold it an angle under the enlarger's light for a close check .
ABOVE Choose from the negative the most important tones and try and cover these with each exposure .
BELOW A standard series of exposure times , from five to twenty seconds , gives a good indication of what the final exposure should be . From the examination of the negative , the central part of the picture with its range of skin tones is the most important , and the test bands were arranged so that the most likely exposure falls in this area . Twenty- second and fifteen - second exposures are too dark , with obvious loss of detail in shadow areas , while five seconds leaves the highlights white and featureless . The ten second exposure is almost right , but perhaps a little too dark .
Place the negative in the enlarger's negative carrier ( emulsion side down ) , cleaning off any dust with a blower , anti- static brush or anti - static gun .
Insert the carrier in the enlarger head . With the room lights out , the enlarger head on and the lens aperture wide open , adjust the enlarger head until the image is focused and the size you have chosen .
Adjust the focus until the image is critically sharp . This can be judged either by eye alone or with the use of a magnifier .
Close down the lens aperture about two stops ( normally this would be f11 ) . With negative of normal density , this will let you use reasonably short exposure times and the lens performance will be at its peak . Greater depth of field will also compensate for any focusing errors .
Under safelight illumination , and with the enlarger lamp off , insert a sheet of normal ( Grade 2 ) paper , emulsion side up , into the printing frame and set the timer to five seconds .
Hold a piece of black card over the sheet of paper , leaving just a quarter of its width exposed , and give a five - second exposure . Move the card along for a second exposure of five seconds . Make third and fourth exposures in the same way .
4. Place a sheet of plain white paper , such as the back of a discarded print , in the easel , and adjust the easel's masks to approximately the proportions that you want . This paper will make composition faster and focusing easier .
5. Turn the safelight on and the room light off . With the lens at full aperture , adjust the enlarger head so that the image fills the frame and is sharply focused .
6. Make final adjustments to the easel masks , as necessary .
7. Reduce the lens aperture by about two stops from fully open . On most lenses this gives the best optical performance .
8. Take a fresh sheet of printing paper and insert it in the easel , emulsion side up , replacing the plain white sheet .
9. Cover all of the exposed paper except for a narrow strip ( about 20 % of the area ) with a piece of thick , opaque card . Make a 5sec exposure .
10. Move the card to uncover a little more of the paper , and give another 5sec exposure . Continue this until all the paper has been exposed ( for the last exposure the sheet should be completely uncovered .
11. Process the paper as described earlier , for one minute in the developer , several seconds in the stop bath , and in the fixer for two minutes .
12. Wash and dry .
ABOVE The area within the dotted lines marks the most important range of contrasts in this image , from the printer's point of view .
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