تويت
التصوير الفوتوغرافي الحديث
تطوير السلبية ..
معدات التطوير ..
DEVELOPING EQUIPMENT
At this point we will talk about only the very simplest equipment which any beginner in photography should have . Later on we can discuss all the special types of developers , developing tanks , and commercial developing equipment in common use . The principles of film development , however , are exactly the same no matter what equipment you use . If you understand how to develop an ordinary roll of film , you will have no trouble later on in learning how to develop commercial and sheet film .
Before you start developing your roll of film , be sure to have all the items of equipment , pictured in Figure 1. These items consist of the following :
1. Developing Tank
2. Thermometer
3. 16 oz . Graduate
4. Stirring Rod
5. Funnel
6. Two metal film clips .
7. Fine synthetic sponge
8. Film developer
9. Fixer
10. Darkroom timer
THE DEVELOPING TANK
The best method of developing roll film is in a developing tank like the one illustrated in Figure 1. There are two general types of roll film tanks , plastic and stainless steel . The plastic tanks are noticeably lower in price , but they are more difficult to load and to keep clean . Since you expect to do photographic work in a serious way , is strongly recommended that you purchase the stainless steel type . This tank will hold either one reel accomodating 120 roll film , or two 35mm reels . The tank shown here is designed for roll film , but there are similar tanks for film packs and small sheet film . Whatever tank you buy , be sure to read the manufacturers instructions carefully , since they may differ somewhat from the general instructions given here . If you want to develop commercial size sheet film ( 4 x 5 or larger ) , you can either do it in an open tray as you would prints , or use commercial film hangers and open tanks . However , at this time , we will confine ourselves to roll - film tanks and discuss open tank development later .
For developing roll film , you will need only one tank . Once the film is loaded into it , you can develop , rinse , fix and wash , all in the same tank without even removing the cover .
Plastic tanks are supplied with agitator rods which can be inserted in the tank opening to engage the reel . The reel should be twirled to and fro once or twice every minute while the film is being developed . Stainless steel tanks are agitated by capping the opening , turning them upside down , and back again . This ensures even development . If you don't agitate the developer , your film will be underdeveloped and streaked , particularly around the heavily exposed areas such as the sky , highlights , faces of people , etc.
THERMOMETER
The modern technique of film development is to use the time - and - temperature method . This means that the film is developed for a definite length of time at a definite temperature . To develop a film properly , you must , therefore , know the temperature of the developing solution . You cannot just guess at it - you must measure it carefully with an accurate thermometer or your negatives will not be correctly developed . For example , a certain film calls for 11 minutes development in a given developer at 65 ° F. The same developer requires only 5 minutes development , or about half as long , at 75 ° F. All developers speed up as they get warmer , and unless you know the temperature at which you are developing , your films may be badly underdeveloped one day and overdeveloped another .
A convenient thermometer to use with a film tank is a simple glass - rod type . To make sure the developer is about the right temperature and doesn't need cooling or warming up , insert the thermometer into the bottle or graduate of developer just before you pour the solution into the tank . Remember that if the developer is appreciably warmer or colder than the air in the room , it will change its temperature , and so you must take that into consideration . This subject will be discussed more fully later .
GRADUATE
You should have at least one good graduate - preferably made of glass . If you don't expect to do a lot of work , a 16 ounce graduate will be big enough , otherwise get two - one 32 ounce and one 8 ounce . Later on when you begin to do a lot of advanced darkroom work , you will want a full assortment .
STIRRING ROD
To dissolve chemicals and mix solutions properly , you must have a good stirring rod . The cheapest - and in many ways the best - is a simple glass rod . However , you may buy a stainless steel or plastic stirring rod if you prefer . You must be more careful to wash the plastic rod thoroughly after use and never let any chemicals dry on it . Glass , while fragile , is much easier to clean .
FUNNEL
You should have a suitable funnel to help pour solutions back into their proper bottles . The few cents spent for a good funnel will save you the time of cleaning up splashed chemicals .
FILM CLIPS
After the roll of film is developed , fixed and washed , it must be hung up to dry . The best method is to hang it from a metal film clip , and weight it at the bottom with another clip . The bottom clip prevents the film from curling up and sticking together while it is drying . The clips made for photographic use are best .
FINE SYNTHETIC SPONGE
When a film is hung up to dry , it is best to wipe off the droplets of water . adhering to its surface . If such droplets are allowed to dry on the film , they will leave a fine residue which may show up in the shadow areas of the final print . A small , very fine textured synthetic sponge is usually used for this purpose , but a piece of photographic chamois or in an emergency a small wad of cotton may also be used . In any case , whatever you use , it must first be thoroughly wet and then squeezed to remove as much surface water as possible . Never under any circumstances allow a dry wiper to touch the delicate surface of wet photographic film .
FILM DEVELOPER
It is probably best , at first , to buy ready - mixed developer of the type that is recommended for your film . However , just as soon as you have learned how to develop your own film , you may prefer to mix your own solutions . There are a large number of prepared developers which will give you satisfactory results . You must , however , use some judgment in selecting the right type , and for that purpose you should be guided by the following suggestions :
1. Don't buy a general - purpose developer which is sold for both film and paper . Papers require contrasty developers , while films require soft - working developers , generally of the fine grain type if the film is small and you expect to enlarge it . A universal film and paper developer is a compromise formula and will not give best results for either film or paper . Better use separate developers if you want good results .
2. Use a medium fine grain developer for film size 24 x 3 % or smaller , particularly if you want to enlarge any of your pictures . For 34 x 444 or larger negatives , you can use an ordinary developer provided you don't expect to enlarge greatly - otherwise use a medium fine grain developer up to 5 x 7. For this and larger sizes , fine grain developers are unnecessary . You will find the regular developers easier to use , and they will generally give better large negatives .
3. Don't use the ultra - fine grain developers until you get to be quite expert and know exactly what you are doing . They are not as suitable for general use .
4. It is always a safe rule to use the developer recommended by the manufacturer of the film or paper you are using .
FIXER
Fixing solutions are quite cheap , so you can buy them ready - mixed , although you can mix your own if you prefer . It is generally best to use separate fixing baths for film and paper , so you should mix about a half gallon for each . However , the same formula can be used for both purposes .
DARKROOM TIMER
For the occasional photographer , a darkroom timer may be dispensed with . A simple kitchen timer or even your own watch will serve , but for serious work , you should have a good darkroom timer , such as the one illustrated in Figure 1 . Such darkroom timers will be discussed in more detail in the next Assignment .
تطوير السلبية ..
معدات التطوير ..
DEVELOPING EQUIPMENT
At this point we will talk about only the very simplest equipment which any beginner in photography should have . Later on we can discuss all the special types of developers , developing tanks , and commercial developing equipment in common use . The principles of film development , however , are exactly the same no matter what equipment you use . If you understand how to develop an ordinary roll of film , you will have no trouble later on in learning how to develop commercial and sheet film .
Before you start developing your roll of film , be sure to have all the items of equipment , pictured in Figure 1. These items consist of the following :
1. Developing Tank
2. Thermometer
3. 16 oz . Graduate
4. Stirring Rod
5. Funnel
6. Two metal film clips .
7. Fine synthetic sponge
8. Film developer
9. Fixer
10. Darkroom timer
THE DEVELOPING TANK
The best method of developing roll film is in a developing tank like the one illustrated in Figure 1. There are two general types of roll film tanks , plastic and stainless steel . The plastic tanks are noticeably lower in price , but they are more difficult to load and to keep clean . Since you expect to do photographic work in a serious way , is strongly recommended that you purchase the stainless steel type . This tank will hold either one reel accomodating 120 roll film , or two 35mm reels . The tank shown here is designed for roll film , but there are similar tanks for film packs and small sheet film . Whatever tank you buy , be sure to read the manufacturers instructions carefully , since they may differ somewhat from the general instructions given here . If you want to develop commercial size sheet film ( 4 x 5 or larger ) , you can either do it in an open tray as you would prints , or use commercial film hangers and open tanks . However , at this time , we will confine ourselves to roll - film tanks and discuss open tank development later .
For developing roll film , you will need only one tank . Once the film is loaded into it , you can develop , rinse , fix and wash , all in the same tank without even removing the cover .
Plastic tanks are supplied with agitator rods which can be inserted in the tank opening to engage the reel . The reel should be twirled to and fro once or twice every minute while the film is being developed . Stainless steel tanks are agitated by capping the opening , turning them upside down , and back again . This ensures even development . If you don't agitate the developer , your film will be underdeveloped and streaked , particularly around the heavily exposed areas such as the sky , highlights , faces of people , etc.
THERMOMETER
The modern technique of film development is to use the time - and - temperature method . This means that the film is developed for a definite length of time at a definite temperature . To develop a film properly , you must , therefore , know the temperature of the developing solution . You cannot just guess at it - you must measure it carefully with an accurate thermometer or your negatives will not be correctly developed . For example , a certain film calls for 11 minutes development in a given developer at 65 ° F. The same developer requires only 5 minutes development , or about half as long , at 75 ° F. All developers speed up as they get warmer , and unless you know the temperature at which you are developing , your films may be badly underdeveloped one day and overdeveloped another .
A convenient thermometer to use with a film tank is a simple glass - rod type . To make sure the developer is about the right temperature and doesn't need cooling or warming up , insert the thermometer into the bottle or graduate of developer just before you pour the solution into the tank . Remember that if the developer is appreciably warmer or colder than the air in the room , it will change its temperature , and so you must take that into consideration . This subject will be discussed more fully later .
GRADUATE
You should have at least one good graduate - preferably made of glass . If you don't expect to do a lot of work , a 16 ounce graduate will be big enough , otherwise get two - one 32 ounce and one 8 ounce . Later on when you begin to do a lot of advanced darkroom work , you will want a full assortment .
STIRRING ROD
To dissolve chemicals and mix solutions properly , you must have a good stirring rod . The cheapest - and in many ways the best - is a simple glass rod . However , you may buy a stainless steel or plastic stirring rod if you prefer . You must be more careful to wash the plastic rod thoroughly after use and never let any chemicals dry on it . Glass , while fragile , is much easier to clean .
FUNNEL
You should have a suitable funnel to help pour solutions back into their proper bottles . The few cents spent for a good funnel will save you the time of cleaning up splashed chemicals .
FILM CLIPS
After the roll of film is developed , fixed and washed , it must be hung up to dry . The best method is to hang it from a metal film clip , and weight it at the bottom with another clip . The bottom clip prevents the film from curling up and sticking together while it is drying . The clips made for photographic use are best .
FINE SYNTHETIC SPONGE
When a film is hung up to dry , it is best to wipe off the droplets of water . adhering to its surface . If such droplets are allowed to dry on the film , they will leave a fine residue which may show up in the shadow areas of the final print . A small , very fine textured synthetic sponge is usually used for this purpose , but a piece of photographic chamois or in an emergency a small wad of cotton may also be used . In any case , whatever you use , it must first be thoroughly wet and then squeezed to remove as much surface water as possible . Never under any circumstances allow a dry wiper to touch the delicate surface of wet photographic film .
FILM DEVELOPER
It is probably best , at first , to buy ready - mixed developer of the type that is recommended for your film . However , just as soon as you have learned how to develop your own film , you may prefer to mix your own solutions . There are a large number of prepared developers which will give you satisfactory results . You must , however , use some judgment in selecting the right type , and for that purpose you should be guided by the following suggestions :
1. Don't buy a general - purpose developer which is sold for both film and paper . Papers require contrasty developers , while films require soft - working developers , generally of the fine grain type if the film is small and you expect to enlarge it . A universal film and paper developer is a compromise formula and will not give best results for either film or paper . Better use separate developers if you want good results .
2. Use a medium fine grain developer for film size 24 x 3 % or smaller , particularly if you want to enlarge any of your pictures . For 34 x 444 or larger negatives , you can use an ordinary developer provided you don't expect to enlarge greatly - otherwise use a medium fine grain developer up to 5 x 7. For this and larger sizes , fine grain developers are unnecessary . You will find the regular developers easier to use , and they will generally give better large negatives .
3. Don't use the ultra - fine grain developers until you get to be quite expert and know exactly what you are doing . They are not as suitable for general use .
4. It is always a safe rule to use the developer recommended by the manufacturer of the film or paper you are using .
FIXER
Fixing solutions are quite cheap , so you can buy them ready - mixed , although you can mix your own if you prefer . It is generally best to use separate fixing baths for film and paper , so you should mix about a half gallon for each . However , the same formula can be used for both purposes .
DARKROOM TIMER
For the occasional photographer , a darkroom timer may be dispensed with . A simple kitchen timer or even your own watch will serve , but for serious work , you should have a good darkroom timer , such as the one illustrated in Figure 1 . Such darkroom timers will be discussed in more detail in the next Assignment .
تعليق