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الطباعة العكسية .. معالجة الألوان والطباعة .. المرشد خطوة بخطوة للتصوير الفوتوغرافي
Reversal printing
Because slides are positive images , to obtain a printed positive direct without using an intermediate negative , you must print on to a special " reversal " material . This can be a reversal paper or a dye destruction material . Reversal paper is a triple - layer color paper which is given black and white development followed by color development ( very similar to slide film processing ) . Ekta- chrome paper is of this kind . Dye destruction materials consist of three sensitive layers containing ready - formed dyes . They require a simpler processing sequence which partly bleaches away unwanted color to leave the image . Cibachrome material uses this dye- bleach , or dye destruction principle . The processing sequences for both reversal sys- tems are shown on pages 174-5 .
Slide film gives an image with contrasty , well saturated colors - ideal for projection - but lacks the compensating orange mask built into color negatives to counteract dye inaccuracies when printing . As a result subtleties of tone and color in the image may be lost when slides are reversal printed , particularly if the original lighting condi- tions were contrasty . To get the best results choose slides which are of medium or low contrast , correctly exposed , and with bright whites and neutral shadows . Avoid printing overexposed , " burnt out " slides .
To print color slides you do not need any additional equipment to that already used for color printing ( see p . 165 ) . As before , you can use either the subtractive or addi- tive methods for filtering the print . For sub- tractive printing you may need a slightly wider range of filters .
As with normal color printing , you must make two test strips - one for exposure and one for filtration . Each packet of reversal material carries filtration suggestions to suit various popular brands of slide film . But it is useful to make a ring - around with a stan- dard , well - exposed slide for reference .
Exposing the slide
Clean the slide carefully before printing . Any specks of dust will appear as black marks on the print and are difficult to retouch . Slides can be printed while they are still in their cardboard mounts , but should always be removed from glass holders . The en- larger masking easel forms black frame edges on reversal prints , so if you want white borders on your print the edges must be fogged , as shown below .
Because you are making a positive from a positive all the normal color printing tech- niques have the opposite effect in reversal printing . For example , more exposure gives a lighter print ; shading darkens the print ; and to reduce a color cast you remove filters of the same color . The table below sum- marizes the main differences between re- versal and ordinary color printing .
All reversal printing materials are very low in contrast to compensate for the high contrast of slide film . This means that to pro- duce the same effects on the image as in negative / positive printing you have to make greater changes in exposure and filtration .
Do not judge your tests or prints until they are dry . When wet both materials appear to have a slight magenta color cast which dis- appears when dry . Prints from both reversal systems should be air - dried ( see p . 168 ) and have a glossy or semi - mat finish .
Differences between reversal and negative / positive color printing
- Reversal
- Neg / Positive
More exposure :
final print lighter .
final print darker .
Less exposure :
final print darker .
final print lighter .
Printing - in :
area is made lighter .
area is made darker .
Shading or dodging :
area is made darker .
area is made lighter .
Covered edges :
gives black borders .
gives white borders .
-------------------------------------
Correcting color casts
- Reversal
- Neg / Positive
Print too yellow :
reduce yellow filters .
add yellow filters .
Print too magenta :
reduce magenta filters .
add magenta filters .
Print too cyan :
reduce cyan filters .
add cyan filters .
Print too blue :
reduce magenta and cyan .
reduce yellow filters .
Print too green :
reduce yellow and cyan .
reduce magenta filters .
Print too red :
reduce yellow and magenta .
reduce cyan filters .
Making white borders on reversal prints
1. Place the slide in the negative carrier . In total darkness expose the image with the masking easel holding the paper flat .
2. Raise the easel masks and place a sheet of glass over the print . The center of the glass should be opaque , over an area slightly smaller than your en- larged image .
3. Remove the negative carrier with the slide . With the easel masks still raised , give twice the original exposure time to fog the paper borders .
4. Process the print following the appropriate procedure shown on pages 174-5 . The final result should have white edges .
Reversal printing
Because slides are positive images , to obtain a printed positive direct without using an intermediate negative , you must print on to a special " reversal " material . This can be a reversal paper or a dye destruction material . Reversal paper is a triple - layer color paper which is given black and white development followed by color development ( very similar to slide film processing ) . Ekta- chrome paper is of this kind . Dye destruction materials consist of three sensitive layers containing ready - formed dyes . They require a simpler processing sequence which partly bleaches away unwanted color to leave the image . Cibachrome material uses this dye- bleach , or dye destruction principle . The processing sequences for both reversal sys- tems are shown on pages 174-5 .
Slide film gives an image with contrasty , well saturated colors - ideal for projection - but lacks the compensating orange mask built into color negatives to counteract dye inaccuracies when printing . As a result subtleties of tone and color in the image may be lost when slides are reversal printed , particularly if the original lighting condi- tions were contrasty . To get the best results choose slides which are of medium or low contrast , correctly exposed , and with bright whites and neutral shadows . Avoid printing overexposed , " burnt out " slides .
To print color slides you do not need any additional equipment to that already used for color printing ( see p . 165 ) . As before , you can use either the subtractive or addi- tive methods for filtering the print . For sub- tractive printing you may need a slightly wider range of filters .
As with normal color printing , you must make two test strips - one for exposure and one for filtration . Each packet of reversal material carries filtration suggestions to suit various popular brands of slide film . But it is useful to make a ring - around with a stan- dard , well - exposed slide for reference .
Exposing the slide
Clean the slide carefully before printing . Any specks of dust will appear as black marks on the print and are difficult to retouch . Slides can be printed while they are still in their cardboard mounts , but should always be removed from glass holders . The en- larger masking easel forms black frame edges on reversal prints , so if you want white borders on your print the edges must be fogged , as shown below .
Because you are making a positive from a positive all the normal color printing tech- niques have the opposite effect in reversal printing . For example , more exposure gives a lighter print ; shading darkens the print ; and to reduce a color cast you remove filters of the same color . The table below sum- marizes the main differences between re- versal and ordinary color printing .
All reversal printing materials are very low in contrast to compensate for the high contrast of slide film . This means that to pro- duce the same effects on the image as in negative / positive printing you have to make greater changes in exposure and filtration .
Do not judge your tests or prints until they are dry . When wet both materials appear to have a slight magenta color cast which dis- appears when dry . Prints from both reversal systems should be air - dried ( see p . 168 ) and have a glossy or semi - mat finish .
Differences between reversal and negative / positive color printing
- Reversal
- Neg / Positive
More exposure :
final print lighter .
final print darker .
Less exposure :
final print darker .
final print lighter .
Printing - in :
area is made lighter .
area is made darker .
Shading or dodging :
area is made darker .
area is made lighter .
Covered edges :
gives black borders .
gives white borders .
-------------------------------------
Correcting color casts
- Reversal
- Neg / Positive
Print too yellow :
reduce yellow filters .
add yellow filters .
Print too magenta :
reduce magenta filters .
add magenta filters .
Print too cyan :
reduce cyan filters .
add cyan filters .
Print too blue :
reduce magenta and cyan .
reduce yellow filters .
Print too green :
reduce yellow and cyan .
reduce magenta filters .
Print too red :
reduce yellow and magenta .
reduce cyan filters .
Making white borders on reversal prints
1. Place the slide in the negative carrier . In total darkness expose the image with the masking easel holding the paper flat .
2. Raise the easel masks and place a sheet of glass over the print . The center of the glass should be opaque , over an area slightly smaller than your en- larged image .
3. Remove the negative carrier with the slide . With the easel masks still raised , give twice the original exposure time to fog the paper borders .
4. Process the print following the appropriate procedure shown on pages 174-5 . The final result should have white edges .
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