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الأفلام الفورية .. اختيار الفيلم .. كيفية التقاط وتطوير الصور بالأبيض والأسود
INSTANT FILMS
For 35mm cameras , Polaroid makes a black - and - white transparency film of medium speed and a normal range of contrast , and also a high - contrast mono- chrome slide emulsion . The film handles as any regular emulsion ; it is supplied in standard cassettes which are loaded , exposed and rewound as any other , and are the newest type of instant film .
Apart from carrying a positive image rather than a negative , the main point of difference in Polaroid 35mm film is that it is exposed through the base of the film rather than through the emulsion side . This means that , when viewed the right way round , these black - and - white transparencies have their delicate emul- sion layer facing towards you . Beware of sliding a loupe across the surface of the film ; the emulsion scratches your camera has an off - the - film metering system , test its performance with this instant film as this kind of metering normally relies on a matt film surface , and the shiny film base may cause incorrect readings .
Processing is straightforward , clean and rapid , but requires Polaroid's own processing unit ( there is a hand - cranked or a powered version ) . The chemicals are provided individually with each roll of film in a sealed box which is discar- ded after use .
The high - contrast Polagraph is different from conventional lith films in both being positive and being panchromatic . As it is as sensitive to red as normal emulsions , it is more suitable for normal camera use .
ABOVE The Polaroid Image System camera uses ultra- sonics to detect the range of the picture subject Optimum shutter speed , aperture , focus and amount of flash are automatically set , but there are override options available .
RIGHT With the Image viewfinder , you get what you see . Instant film is of course a marvellous check on the possibilities for the final print before switching to conventional film , and is often used in this way by professional photographers .
ABOVE PolaPan film gives a positive monochrome 35mm image , and is suited to use in a normal SLR . However , when not backlit PolaPan slides appear to be negatives !
The other , older varieties of instant film produce prints as an end - product and must be loaded into special holders to fit on medium - format or large- format cameras , or must be used in special Polaroid Land cameras . There is a normal - contrast , medium - high speed film ( Types 552 and 52 , medium- format and 4 × 5in respectively ) , a high - contrast film ( Type 51 , 4 × 5in ) , a high- speed film ( Types 87 , 107 and 57 , the first two medium - format , the last 4 × 5in ) , and a fine - grained normal - contrast film that produces a high - quality negative in addition to the print ( Types 665 and 55 , medium - format and 4 × 5in re- spectively ) .
These are peel - apart films ; after exposure , they are processed by first being drawn through a set of metal rollers ( which squeeze out a pod of chemicals ) , then the print is peeled away from the remainder of the thin packet . The processing times and temperature differ from film to film , and are given on each pack .
The most popular use of instant films among professional photographers is as a form of testing . With an important shot , or one that carries some uncer- tainty , such as in the exposure setting , it is a simple matter to make a test shot on one of these instant films first . Then , if necessary , any changes can quickly be made before shooting on regular film . The positive - negative films types 665 and 55 , however , offer a greater benefit to the black - and - white photographer . The negative is very fine - grained and immediately verifiable a valid alterna- tive to normal black - and - white film .
INSTANT FILMS
For 35mm cameras , Polaroid makes a black - and - white transparency film of medium speed and a normal range of contrast , and also a high - contrast mono- chrome slide emulsion . The film handles as any regular emulsion ; it is supplied in standard cassettes which are loaded , exposed and rewound as any other , and are the newest type of instant film .
Apart from carrying a positive image rather than a negative , the main point of difference in Polaroid 35mm film is that it is exposed through the base of the film rather than through the emulsion side . This means that , when viewed the right way round , these black - and - white transparencies have their delicate emul- sion layer facing towards you . Beware of sliding a loupe across the surface of the film ; the emulsion scratches your camera has an off - the - film metering system , test its performance with this instant film as this kind of metering normally relies on a matt film surface , and the shiny film base may cause incorrect readings .
Processing is straightforward , clean and rapid , but requires Polaroid's own processing unit ( there is a hand - cranked or a powered version ) . The chemicals are provided individually with each roll of film in a sealed box which is discar- ded after use .
The high - contrast Polagraph is different from conventional lith films in both being positive and being panchromatic . As it is as sensitive to red as normal emulsions , it is more suitable for normal camera use .
ABOVE The Polaroid Image System camera uses ultra- sonics to detect the range of the picture subject Optimum shutter speed , aperture , focus and amount of flash are automatically set , but there are override options available .
RIGHT With the Image viewfinder , you get what you see . Instant film is of course a marvellous check on the possibilities for the final print before switching to conventional film , and is often used in this way by professional photographers .
ABOVE PolaPan film gives a positive monochrome 35mm image , and is suited to use in a normal SLR . However , when not backlit PolaPan slides appear to be negatives !
The other , older varieties of instant film produce prints as an end - product and must be loaded into special holders to fit on medium - format or large- format cameras , or must be used in special Polaroid Land cameras . There is a normal - contrast , medium - high speed film ( Types 552 and 52 , medium- format and 4 × 5in respectively ) , a high - contrast film ( Type 51 , 4 × 5in ) , a high- speed film ( Types 87 , 107 and 57 , the first two medium - format , the last 4 × 5in ) , and a fine - grained normal - contrast film that produces a high - quality negative in addition to the print ( Types 665 and 55 , medium - format and 4 × 5in re- spectively ) .
These are peel - apart films ; after exposure , they are processed by first being drawn through a set of metal rollers ( which squeeze out a pod of chemicals ) , then the print is peeled away from the remainder of the thin packet . The processing times and temperature differ from film to film , and are given on each pack .
The most popular use of instant films among professional photographers is as a form of testing . With an important shot , or one that carries some uncer- tainty , such as in the exposure setting , it is a simple matter to make a test shot on one of these instant films first . Then , if necessary , any changes can quickly be made before shooting on regular film . The positive - negative films types 665 and 55 , however , offer a greater benefit to the black - and - white photographer . The negative is very fine - grained and immediately verifiable a valid alterna- tive to normal black - and - white film .
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