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إجراء التعريض للطباعة .. الطباعة .. كيفية التقاط وتطوير الصور الملونة
PRINTING
MAKING THE PRINT EXPOSURE
Although the colour filtration and exposure times vary from process to : process , the essentials of making a colour enlargement are fairly standard . At the start , it may take you several tries before you arrive close to the best filtra- tions and exposures ; the light output and optical parts of enlargers differ . If you use a simple enlarger with a black - and - white head , place a UV - absorbing 2B or CP2B filter permanently under the light head and above the negative carrier .
The first step after processing the film is to select the negatives or slides for printing . With slides , a light - box is sufficient to judge a well - exposed frame , but with negatives , make a contact sheet . As well as giving you your first look at the images , it will serve as a filing reference for later printing . Set the enlarger head at a height that will illuminate an area slightly larger than a 8 × 10 - in ( 20 × 26 - cm ) sheet of paper with the negative carrier empty . Judging the expo- sure and filtration is something of a chicken - and - egg situation , because you must first have some experience with the enlarger and negative / paper com- bination that you regularly use . After you have set up your system for the first time , this will be no problem ; for now , assume that you have calibrated every- thing . Set the filtration , aperture and timer according to previous test prints . Place one film , cut into strips of six frames each , in a contact - printer or under a plain sheet of glass . In safelighting , place a sheet of printing paper underneath and expose .
Having selected a negative or slide to print , place it in the negative carrier with the emulsion side down , facing the lens . Place the negative carrier in the enlarger , switch on the enlarger light , open the aperture fully , and adjust the head so that the image is composed on the easel according to your require- ments and is in focus . This is easier to do if the room lights are switched off . To substitute for the thickness of the printing paper , place a piece of white paper in the easel for this step .
Select the filtration and lens aperture as recommended by the paper manufacturer . With slide printing , there will also be a difference depending on which brand of original film you used ; Kodachrome will need less cyan and a little less magenta than will Ektachrome . Under safelighting or in total darkness replace the blank paper in the easel with a sheet of unexposed printing paper , emulsion side up .
Make a series of test exposures at intervals of five seconds . Use a piece of dark card to cover all of the paper except for a strip . With each successive exposure , uncover another strip . This first test print can then be used , once processed , to determine the best exposure and filtration for the final print . When you come to make this final print , the basic steps are the same . Keep a note of the settings that give you the best result ; this will save time and paper if you come to make another print of the same photograph .
ABOVE Selecting the filtration and lens aperture for slide printing depends upon the brand of film . Kodachrome ( above ) will need less cyan and a little less magenta than will Ektachrome .
BELOW RIGHT An example of a test print , from which to assess the best filtration and exposure for the final print .
The test strip procedure
1 Place the negative in the enlarger's negative carrier ( emulsion side down ) , cleaning off any dust preferably with an anti- static brush or a blower .
2 Insert the carrier in the enlarger head . With the room lights out , the enlarger lamp on and the lens aperture wide open , adjust the enlarger head until the image is focused and to the size you have chosen .
3 Make fine adjustments to the focus until the image is critically sharp . You can do this by eye or by using a focus magnifier which enables you to check the sharpness of the film's grain ; ( irrespective of whether the image is sharp , as long as the grain is focused you will have the sharpest print possible ) .
4 Close down the lens aperture about two stops ( normally this would be f11 ) . With a negative of normal density this will let you use reasonably short exposure times , and the lens performance will be at its peak . The increased depth of field will also compensate ' or slight focusing errors .
5 Under safelight illumination , and with the enlarger lamp off , insert a sheet of normal ( Grade 2 ) paper , emulsion side up , into the printing frame . Set the timer to five seconds .
6 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 second exposure of five seconds . Make third and fourth in the same way . The whole sheet will be exposed for the final exposure . Process as an ordinary print .
PRINTING
MAKING THE PRINT EXPOSURE
Although the colour filtration and exposure times vary from process to : process , the essentials of making a colour enlargement are fairly standard . At the start , it may take you several tries before you arrive close to the best filtra- tions and exposures ; the light output and optical parts of enlargers differ . If you use a simple enlarger with a black - and - white head , place a UV - absorbing 2B or CP2B filter permanently under the light head and above the negative carrier .
The first step after processing the film is to select the negatives or slides for printing . With slides , a light - box is sufficient to judge a well - exposed frame , but with negatives , make a contact sheet . As well as giving you your first look at the images , it will serve as a filing reference for later printing . Set the enlarger head at a height that will illuminate an area slightly larger than a 8 × 10 - in ( 20 × 26 - cm ) sheet of paper with the negative carrier empty . Judging the expo- sure and filtration is something of a chicken - and - egg situation , because you must first have some experience with the enlarger and negative / paper com- bination that you regularly use . After you have set up your system for the first time , this will be no problem ; for now , assume that you have calibrated every- thing . Set the filtration , aperture and timer according to previous test prints . Place one film , cut into strips of six frames each , in a contact - printer or under a plain sheet of glass . In safelighting , place a sheet of printing paper underneath and expose .
Having selected a negative or slide to print , place it in the negative carrier with the emulsion side down , facing the lens . Place the negative carrier in the enlarger , switch on the enlarger light , open the aperture fully , and adjust the head so that the image is composed on the easel according to your require- ments and is in focus . This is easier to do if the room lights are switched off . To substitute for the thickness of the printing paper , place a piece of white paper in the easel for this step .
Select the filtration and lens aperture as recommended by the paper manufacturer . With slide printing , there will also be a difference depending on which brand of original film you used ; Kodachrome will need less cyan and a little less magenta than will Ektachrome . Under safelighting or in total darkness replace the blank paper in the easel with a sheet of unexposed printing paper , emulsion side up .
Make a series of test exposures at intervals of five seconds . Use a piece of dark card to cover all of the paper except for a strip . With each successive exposure , uncover another strip . This first test print can then be used , once processed , to determine the best exposure and filtration for the final print . When you come to make this final print , the basic steps are the same . Keep a note of the settings that give you the best result ; this will save time and paper if you come to make another print of the same photograph .
ABOVE Selecting the filtration and lens aperture for slide printing depends upon the brand of film . Kodachrome ( above ) will need less cyan and a little less magenta than will Ektachrome .
BELOW RIGHT An example of a test print , from which to assess the best filtration and exposure for the final print .
The test strip procedure
1 Place the negative in the enlarger's negative carrier ( emulsion side down ) , cleaning off any dust preferably with an anti- static brush or a blower .
2 Insert the carrier in the enlarger head . With the room lights out , the enlarger lamp on and the lens aperture wide open , adjust the enlarger head until the image is focused and to the size you have chosen .
3 Make fine adjustments to the focus until the image is critically sharp . You can do this by eye or by using a focus magnifier which enables you to check the sharpness of the film's grain ; ( irrespective of whether the image is sharp , as long as the grain is focused you will have the sharpest print possible ) .
4 Close down the lens aperture about two stops ( normally this would be f11 ) . With a negative of normal density this will let you use reasonably short exposure times , and the lens performance will be at its peak . The increased depth of field will also compensate ' or slight focusing errors .
5 Under safelight illumination , and with the enlarger lamp off , insert a sheet of normal ( Grade 2 ) paper , emulsion side up , into the printing frame . Set the timer to five seconds .
6 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 second exposure of five seconds . Make third and fourth in the same way . The whole sheet will be exposed for the final exposure . Process as an ordinary print .
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