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الطباعة العكسية - أوراق عكسية .. معالجة الألوان والطباعة .. المرشد خطوة بخطوة للتصوير الفوتوغرافي
Reversal printing - reversal papers
In reversal paper the final dyes are formed chemically during processing , in a similar manner to ordinary color paper . However , reversal paper is designed for full reversal processing , like that used for slide film . It also produces images with much lower contrast than ordinary color paper .
Processing first forms black and white negatives . The remaining unexposed emul- sion is then fogged and color developed , and bleaching removes all the silver . Processing takes eighteen minutes and is carried out at a temperature of 86 ° F ( 30 ° C ) . The tolerance of the developer is only ± 1.8 ° F ; all other solutions have a tolerance of ± 3 ° F .
Reversal paper is supplied in packs , which give the filter ratings and exposure rating for that particular batch . These enable you to calculate the new exposure and filter settings when changing from one paper batch to another , see page 169. It is best to start working with this paper by using a good quality slide , with the filters all set to zero . You can then make a first exposure test strip , which will serve as a guide for more difficult slides . Most reversal papers are much slower than ordinary papers so longer exposure times are necessary .
Always wait until your test strip print is dry before assessing it . The best way to judge results is to look for detail in high- lights and shadows . From this you can decide by how much to shorten or lengthen the exposure . The color balance on the second , filtration test strip can be assessed by checking the midtones of the transparency against the print .
Ektachrome reversal paper
The first , black and white develop- ment forms black silver negatives in the three emulsion layers . No dyes are present .
Original transparency
Black and white development
Reversal : color development
Bleach
Final print
The color developer fogs the film . forms positive silver and dye images . and stabilizes the dyes . The unwanted silver is removed by the bleach to leave three positive images in colored dyes .
Processing Ektachrome color prints
In complete darkness load the exposed print , emulsion side in- ward , into the developing drum . Replace the drum lid and turn on normal lighting . Put on the rubber gloves and replace the drum in the water bath .
The temperature of all the sol- utions and the washes should be 86 F ( 30 C ) . The temperature range of the developer is only 1-8 ° F : the range for the other solutions is shown in the table , far right . You need a separate bowl as a warm water bath for the solutions .
1. After pre - wetting the print . bring the first developer up to 86 F ( 30 ° C ) before pouring it into the drum . Agitate , then drain as suggested .
2. Pour in the first wash . Agitate for the recommended time , then repeat twice to prevent any contamination of the next chemical .
3. Add the color developer , agi- tate , then drain the tank at the end of the recommended time .
4. Wash the print to remove all traces of developer .
5. Add the bleach / fix to the drum , agitate , then pour it away .
6. Wash the print for the recommended time .
Finally , air - dry the print in a drying rack like that shown above , right .
Note that all times , right , include a ten - second drain at the end of each step .
Reversal printing - reversal papers
In reversal paper the final dyes are formed chemically during processing , in a similar manner to ordinary color paper . However , reversal paper is designed for full reversal processing , like that used for slide film . It also produces images with much lower contrast than ordinary color paper .
Processing first forms black and white negatives . The remaining unexposed emul- sion is then fogged and color developed , and bleaching removes all the silver . Processing takes eighteen minutes and is carried out at a temperature of 86 ° F ( 30 ° C ) . The tolerance of the developer is only ± 1.8 ° F ; all other solutions have a tolerance of ± 3 ° F .
Reversal paper is supplied in packs , which give the filter ratings and exposure rating for that particular batch . These enable you to calculate the new exposure and filter settings when changing from one paper batch to another , see page 169. It is best to start working with this paper by using a good quality slide , with the filters all set to zero . You can then make a first exposure test strip , which will serve as a guide for more difficult slides . Most reversal papers are much slower than ordinary papers so longer exposure times are necessary .
Always wait until your test strip print is dry before assessing it . The best way to judge results is to look for detail in high- lights and shadows . From this you can decide by how much to shorten or lengthen the exposure . The color balance on the second , filtration test strip can be assessed by checking the midtones of the transparency against the print .
Ektachrome reversal paper
The first , black and white develop- ment forms black silver negatives in the three emulsion layers . No dyes are present .
Original transparency
Black and white development
Reversal : color development
Bleach
Final print
The color developer fogs the film . forms positive silver and dye images . and stabilizes the dyes . The unwanted silver is removed by the bleach to leave three positive images in colored dyes .
Processing Ektachrome color prints
In complete darkness load the exposed print , emulsion side in- ward , into the developing drum . Replace the drum lid and turn on normal lighting . Put on the rubber gloves and replace the drum in the water bath .
The temperature of all the sol- utions and the washes should be 86 F ( 30 C ) . The temperature range of the developer is only 1-8 ° F : the range for the other solutions is shown in the table , far right . You need a separate bowl as a warm water bath for the solutions .
1. After pre - wetting the print . bring the first developer up to 86 F ( 30 ° C ) before pouring it into the drum . Agitate , then drain as suggested .
2. Pour in the first wash . Agitate for the recommended time , then repeat twice to prevent any contamination of the next chemical .
3. Add the color developer , agi- tate , then drain the tank at the end of the recommended time .
4. Wash the print to remove all traces of developer .
5. Add the bleach / fix to the drum , agitate , then pour it away .
6. Wash the print for the recommended time .
Finally , air - dry the print in a drying rack like that shown above , right .
Note that all times , right , include a ten - second drain at the end of each step .
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