تويت
استخدام الفيلم بحذر .. اختيار الفيلم .. كيفية التقاط وتطوير الصور بالأبيض والأسود
CAREFUL FILM USE
In most ways , black - and - white film is more rugged than colour , with more exposure latitude and less susceptibility to ageing and poor storage . Neverthe- less there is no reason to be sloppy in the way you treat it : all film is perishable and gives its best results if kept in the recommended conditions and processed as soon as possible after it has been exposed .
STORAGE
As film ages , it slowly loses both sensitivity and contrast . This is an admittedly slow process with black - and - white film , but it happens even so . Part of the information printed on the box is the date by which it should be used , and this applies if the film is kept under ' normal ' conditions - room temperature and moderately dry air . Two things accelerate this ageing process : heat and humid- ity . Be careful in either condition to avoid keeping unprocessed film for long ; when the two are combined the film ages even more rapidly .
Conversely , cooling film slows down the ageing process . To keep film almost indefinitely , seal it in a moisture - proof container ( the 35mm film can will do ) and put it in the freezer compartment of a refrigerator at -18 ° C ( 0 ° F ) or below . When you are ready to use it , allow enough time for it to reach room temperature before opening the container , or else moisture is liable to con- dense onto the film itself .
A more generally useful storage method is in an ordinary refrigerator at about 4 ° C ( 39 ° F ) . Again , allow time for it to warm up before use .
CARRYING FILM
On a trip , storage conditions are likely to be less than ideal . Keep the film out of direct sunlight , below 16 ° C ( 60 ° F ) for as much of the time as possible , and at a relative humidity of less than 60 % . In really hot sticky weather , an insulated container such as a styrofoam picnic box is a good idea , and a packet of silica gel crystals will keep the air inside dry .
X - RAYS
X - rays are radiation - like light but a much shorter wavelength- and will fog film if the dose is high enough . Nearly all airports now use X - ray security machines , and while most are designed to give a dose that is too small to harm film , the effect is cumulative . So , if you carry the same film through several airports , it may receive enough X - rays to fog it . Also , high - speed films are more susceptible than regular emulsions . Black - and - white films , fortunately , suffer less than colour , but try and avoid letting them pass through machines . In the United States you are entitled to ask for a hand - inspection , but in other coun- tries this is not always possible . Lead - lined bags sold in photo stores give some protection , and checked baggage for the hold is far less likely to be subjected to X - ray inspection .
ABOVE Silica gel is a dessiccant that soaks up moisture from the air like a sponge . Pack it with film and equipment if the humidity is high ( but not in dry heat as it will then make the film brittle ) . For the best drying effect , use airtight cases and pack them tightly so that there is little empty space . One ounce of silica gel will keep nearly 1 cubic ft ( 0.3 cubic m ) of air dry . It can be dried in an oven for reuse .
SENSITIVE SAFETY FILM DO NOT X - RAY KEEP AWAY FROM HEAT
A prominent label is a useful precaution for camera cases travelling by air . If film is unavoidably subjected to X - ray examination , the direction the cassettes are facing may influence the amount of damage .
CAREFUL FILM USE
In most ways , black - and - white film is more rugged than colour , with more exposure latitude and less susceptibility to ageing and poor storage . Neverthe- less there is no reason to be sloppy in the way you treat it : all film is perishable and gives its best results if kept in the recommended conditions and processed as soon as possible after it has been exposed .
STORAGE
As film ages , it slowly loses both sensitivity and contrast . This is an admittedly slow process with black - and - white film , but it happens even so . Part of the information printed on the box is the date by which it should be used , and this applies if the film is kept under ' normal ' conditions - room temperature and moderately dry air . Two things accelerate this ageing process : heat and humid- ity . Be careful in either condition to avoid keeping unprocessed film for long ; when the two are combined the film ages even more rapidly .
Conversely , cooling film slows down the ageing process . To keep film almost indefinitely , seal it in a moisture - proof container ( the 35mm film can will do ) and put it in the freezer compartment of a refrigerator at -18 ° C ( 0 ° F ) or below . When you are ready to use it , allow enough time for it to reach room temperature before opening the container , or else moisture is liable to con- dense onto the film itself .
A more generally useful storage method is in an ordinary refrigerator at about 4 ° C ( 39 ° F ) . Again , allow time for it to warm up before use .
CARRYING FILM
On a trip , storage conditions are likely to be less than ideal . Keep the film out of direct sunlight , below 16 ° C ( 60 ° F ) for as much of the time as possible , and at a relative humidity of less than 60 % . In really hot sticky weather , an insulated container such as a styrofoam picnic box is a good idea , and a packet of silica gel crystals will keep the air inside dry .
X - RAYS
X - rays are radiation - like light but a much shorter wavelength- and will fog film if the dose is high enough . Nearly all airports now use X - ray security machines , and while most are designed to give a dose that is too small to harm film , the effect is cumulative . So , if you carry the same film through several airports , it may receive enough X - rays to fog it . Also , high - speed films are more susceptible than regular emulsions . Black - and - white films , fortunately , suffer less than colour , but try and avoid letting them pass through machines . In the United States you are entitled to ask for a hand - inspection , but in other coun- tries this is not always possible . Lead - lined bags sold in photo stores give some protection , and checked baggage for the hold is far less likely to be subjected to X - ray inspection .
ABOVE Silica gel is a dessiccant that soaks up moisture from the air like a sponge . Pack it with film and equipment if the humidity is high ( but not in dry heat as it will then make the film brittle ) . For the best drying effect , use airtight cases and pack them tightly so that there is little empty space . One ounce of silica gel will keep nearly 1 cubic ft ( 0.3 cubic m ) of air dry . It can be dried in an oven for reuse .
SENSITIVE SAFETY FILM DO NOT X - RAY KEEP AWAY FROM HEAT
A prominent label is a useful precaution for camera cases travelling by air . If film is unavoidably subjected to X - ray examination , the direction the cassettes are facing may influence the amount of damage .
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