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تطوير السلبية ..
كيفية التعامل مع ورقة فيلم وتطويرها - ٢ -
LOADING FILM HANGERS .
Sheet film is generally developed in open tanks and in this process each sheet of film is loaded into its own stainless steel hanger . This permits it to be handled easily and safely so that there . no danger of the delicate emulsion surface being scratched or damaged in subsequent processing .
Figure 19 shows a simple system for storing film hangers for the photographer who does a relatively small business . The larger commercial studios will , of course , have more elaborate systems . If only one set of brackets is provided , they should be used for the empty hangers , and the loaded hangers may be stacked up against the wall at the back of the processing table or bench in the same manner as the film holders when they are loaded . Here , too , if the table or bench top is covered with ribbed rubber sheeting , the loaded hangers won't slip .
Fig . 19 Shelf brackets used to store film hangers .
To load a film processing hanger , spring back the hinged top channel of the hanger to expose the side channels . ( See Figure 20. ) Hold the hanger in your left hand and pick up the sheet of film in your right . Slide the film into the side channels carefully and make sure that it enters the bottom channel as well . ( Figure 21. ) With larger film sheets , it may be necessary to guide the film into the bottom channel . At any rate , be sure to check that the film has entered . the channel no matter what film size you use . Now spring the top hinged section back into place . If it does not close properly , the film is incorrectly inserted . Check again to be sure that it is seated properly in all four channels .
Fig . 20 Flip back the top spring loaded channel prior to inserting film .
Fig . 21 Make sure film enters the bottom channel of the hanger . If not , the film may be buckled when the top channel is flipped back in place .
PRECAUTIONS WHEN LOADING AND UNLOADING HANGERS . When a stack of hangers has been loaded ( Figure 22 ) , handle them carefully as a unit with both hands . This will enable you to transfer the group of hangers from one tank to another in the subsequent processing procedure and will prevent the gouging or scratching of films by the hangers next to them should they get out of position . This is particularly true when you are processing 8 x 10 sheet film . Because of their larger size , they have more of a tendency to fall out of the hanger when handled roughly , so such film should never be shaken . in their hangers , particularly when they are in solutions .
Fig . 22 As film hangers are loaded , stack them as shown so they may be handled as a unit .
DEVELOPING SHEET FILM BY THE OPEN TANK METHOD . There are number of compact sheet film tanks taking 4 x 5 film and smaller which do not . require film hangers . Instead , the sheets are slipped into grooves , a light tight cover placed over the tank , and then the light turned on . All succeeding operations can be performed in white light as with ordinary roll film tanks . The principle disadvantage of such tanks is that they are usually so compact there isn't adequate separation between sheets to permit even development . It is also quite difficult to agitate properly ; the films cannot be rotated or lifted out of the tank . A tank that holds a dozen 4 x 5 sheet films and yet takes no more than a half gallon of solution is usually too compact to provide even development . However , if you use only every other groove , reducing the capacity to six sheets of film , and agitate for at least 10 seconds out of every half - minute , such tanks may be satisfactory .
The standard method for developing sheet film is to place each sheet in its own hanger and then process a number of them together large open tanks . By this means the films are given maximum protection against damage , and can be handled most quickly . This is the method that will be described here in detail .
You will need three processing tanks in addition to the washing tank . The processing tanks are for the developer , the rinse ( or stop bath ) , and the fixer . The washer may be a tank similar to the others , or one specially designed for washing purposes , in which case it will be in the wash sink rather than on the processing table . We will not go into a discussion of these tanks at this time , since this will be taken up in the next Assignment .
Begin by laying out the tanks so that the developer tank is to the left , followed by the rinse , and then by the fixer tank . All three processing tanks should be quite close to , if not in , the sink itself so that you can transfer the film from one tank to the next without dripping solution onto the work bench . surface . For sheet film under 5 x 7 , the film hangers are small enough so that a number of them can be handled as a unit without too much difficulty . However , for 8 x 10 films , it is best to use a rack in which the hangers are supported and given greater protection . Both systems will be illustrated here .
Before you start , check the developer temperature and determine the correct developing time for that temperature . Set the darkroom timer for this time interval . Lay out the exposed film holders so that they will be at hand and when . you are sure that everything else is in proper position so that you can continue in total darkness , switch off the light . Then proceed as follows :
1. Load the film hangers as previously described . Do not load any more hangers than you can safely accomodate in the developer tank at one time . A tank is loaded to full capacity when there is about 1/2 inch between films of 5 x 7 or smaller sheets , and 1 inch for 8 x 10. Greater crowding isn't safe ; there is danger of scratching the film , and the flow of developer is impeded so that uneven development may result .
2. Start the timer . Lift all the loaded hangers as one unit and lower them smoothly , yet quickly , into the developer . ( See Figures 23 & 24. ) Immediately after immersion , lift them all a half inch or so and bring them down sharply to tap the crossbars against the top of the tank . Do this two or three times to liberate any air bubbles that may be clinging to the film surface . Then separate the hangers to provide uniform spacing between them .
3. Wait one minute , then lift the hangers out of the developer , drain for a second or so from one corner and lower them again . ( See Figure 25. ) If they have bunched together , separate procedure results in a uniform degree of agitation . Repeat it once every minute during the process of development .
Some photographers prefer to agitate one film at a time . This procedure is satisfactory in a large tank with widely separated films , but it is not recommended when the tank is well filled . It is too easy , when lowering a metal hanger , to gouge a chunk of emulsion from an adjacent film .
Just as bad is a violent pumping up . and down of the hangers , particularly in a crowded tank . Any rapid up and down . movement will force the developer through . the small holes in the bottom of each hanger . The narrow , but regular , currents of fresh developer sweeping across the film will increase the rate of development above . the holes and the result will be a badly streaked negative , one streak for each hole . If the hangers are lifted completely out of the solution , allowed to drain from the corners and lowered gently , the developer
Fig . 23 With solutions at the proper temperature , and hangers properly loaded , development may begin . Pick up hangers as shown , and lower into developer tank . It is advisable to practice this in light .
Fig . 24 Larger film hangers are more easily handled in specially built racks . Practice placing hangers in the rack before trying to do it in the dark .
Fig . 25 For agitation , lift rack entirely out of the solution . Drain as shown for one second and lower again into the solution .
will flow uniformly around the film rather than violently through the hangers and will set up no regular flow pattern .
4. When development is complete , transfer the films as a unit to the rinse bath . Lift and drain two or three times , and transfer to the fixing bath . Agitate again several times and then allow them to fix undisturbed , although if you are in a hurry , you can reduce fixing time slightly by constant agitation .
5. After fixing , transfer the films to the washer for a 30 minute wash in running water . After washing , the films may be swabbed to remove excess water or given a short rinse in a wetting agent , as has been described for roll film processing . They are then hung up to dry .
It is common practice to dry sheet film in their hangers , but it is generally better practice , at least in the larger sizes , to remove the films from their hangers and hang them on the film clips where they can dry more quickly and uniformly . This is shown in Figure 26 .
Fig . 26 After a final rinse in a wetting agent , the film is ready for drying . It is best to hang the film as shown .
In this part of the Assignment , we have discussed the general procedures used in the development of roll and sheet film . We have given you the principle reasons for each step taken and have pointed out some of the pitfalls to be avoided . If you follow the instructions given here , you should be able to develop your exposed film properly and get good results . Most photographers never get beyond this point . As a student of photography , however , you should have a much fuller understanding of these basic procedures so that you will not follow them slavishly when conditions change or photographic materials are improved .
تطوير السلبية ..
كيفية التعامل مع ورقة فيلم وتطويرها - ٢ -
LOADING FILM HANGERS .
Sheet film is generally developed in open tanks and in this process each sheet of film is loaded into its own stainless steel hanger . This permits it to be handled easily and safely so that there . no danger of the delicate emulsion surface being scratched or damaged in subsequent processing .
Figure 19 shows a simple system for storing film hangers for the photographer who does a relatively small business . The larger commercial studios will , of course , have more elaborate systems . If only one set of brackets is provided , they should be used for the empty hangers , and the loaded hangers may be stacked up against the wall at the back of the processing table or bench in the same manner as the film holders when they are loaded . Here , too , if the table or bench top is covered with ribbed rubber sheeting , the loaded hangers won't slip .
Fig . 19 Shelf brackets used to store film hangers .
To load a film processing hanger , spring back the hinged top channel of the hanger to expose the side channels . ( See Figure 20. ) Hold the hanger in your left hand and pick up the sheet of film in your right . Slide the film into the side channels carefully and make sure that it enters the bottom channel as well . ( Figure 21. ) With larger film sheets , it may be necessary to guide the film into the bottom channel . At any rate , be sure to check that the film has entered . the channel no matter what film size you use . Now spring the top hinged section back into place . If it does not close properly , the film is incorrectly inserted . Check again to be sure that it is seated properly in all four channels .
Fig . 20 Flip back the top spring loaded channel prior to inserting film .
Fig . 21 Make sure film enters the bottom channel of the hanger . If not , the film may be buckled when the top channel is flipped back in place .
PRECAUTIONS WHEN LOADING AND UNLOADING HANGERS . When a stack of hangers has been loaded ( Figure 22 ) , handle them carefully as a unit with both hands . This will enable you to transfer the group of hangers from one tank to another in the subsequent processing procedure and will prevent the gouging or scratching of films by the hangers next to them should they get out of position . This is particularly true when you are processing 8 x 10 sheet film . Because of their larger size , they have more of a tendency to fall out of the hanger when handled roughly , so such film should never be shaken . in their hangers , particularly when they are in solutions .
Fig . 22 As film hangers are loaded , stack them as shown so they may be handled as a unit .
DEVELOPING SHEET FILM BY THE OPEN TANK METHOD . There are number of compact sheet film tanks taking 4 x 5 film and smaller which do not . require film hangers . Instead , the sheets are slipped into grooves , a light tight cover placed over the tank , and then the light turned on . All succeeding operations can be performed in white light as with ordinary roll film tanks . The principle disadvantage of such tanks is that they are usually so compact there isn't adequate separation between sheets to permit even development . It is also quite difficult to agitate properly ; the films cannot be rotated or lifted out of the tank . A tank that holds a dozen 4 x 5 sheet films and yet takes no more than a half gallon of solution is usually too compact to provide even development . However , if you use only every other groove , reducing the capacity to six sheets of film , and agitate for at least 10 seconds out of every half - minute , such tanks may be satisfactory .
The standard method for developing sheet film is to place each sheet in its own hanger and then process a number of them together large open tanks . By this means the films are given maximum protection against damage , and can be handled most quickly . This is the method that will be described here in detail .
You will need three processing tanks in addition to the washing tank . The processing tanks are for the developer , the rinse ( or stop bath ) , and the fixer . The washer may be a tank similar to the others , or one specially designed for washing purposes , in which case it will be in the wash sink rather than on the processing table . We will not go into a discussion of these tanks at this time , since this will be taken up in the next Assignment .
Begin by laying out the tanks so that the developer tank is to the left , followed by the rinse , and then by the fixer tank . All three processing tanks should be quite close to , if not in , the sink itself so that you can transfer the film from one tank to the next without dripping solution onto the work bench . surface . For sheet film under 5 x 7 , the film hangers are small enough so that a number of them can be handled as a unit without too much difficulty . However , for 8 x 10 films , it is best to use a rack in which the hangers are supported and given greater protection . Both systems will be illustrated here .
Before you start , check the developer temperature and determine the correct developing time for that temperature . Set the darkroom timer for this time interval . Lay out the exposed film holders so that they will be at hand and when . you are sure that everything else is in proper position so that you can continue in total darkness , switch off the light . Then proceed as follows :
1. Load the film hangers as previously described . Do not load any more hangers than you can safely accomodate in the developer tank at one time . A tank is loaded to full capacity when there is about 1/2 inch between films of 5 x 7 or smaller sheets , and 1 inch for 8 x 10. Greater crowding isn't safe ; there is danger of scratching the film , and the flow of developer is impeded so that uneven development may result .
2. Start the timer . Lift all the loaded hangers as one unit and lower them smoothly , yet quickly , into the developer . ( See Figures 23 & 24. ) Immediately after immersion , lift them all a half inch or so and bring them down sharply to tap the crossbars against the top of the tank . Do this two or three times to liberate any air bubbles that may be clinging to the film surface . Then separate the hangers to provide uniform spacing between them .
3. Wait one minute , then lift the hangers out of the developer , drain for a second or so from one corner and lower them again . ( See Figure 25. ) If they have bunched together , separate procedure results in a uniform degree of agitation . Repeat it once every minute during the process of development .
Some photographers prefer to agitate one film at a time . This procedure is satisfactory in a large tank with widely separated films , but it is not recommended when the tank is well filled . It is too easy , when lowering a metal hanger , to gouge a chunk of emulsion from an adjacent film .
Just as bad is a violent pumping up . and down of the hangers , particularly in a crowded tank . Any rapid up and down . movement will force the developer through . the small holes in the bottom of each hanger . The narrow , but regular , currents of fresh developer sweeping across the film will increase the rate of development above . the holes and the result will be a badly streaked negative , one streak for each hole . If the hangers are lifted completely out of the solution , allowed to drain from the corners and lowered gently , the developer
Fig . 23 With solutions at the proper temperature , and hangers properly loaded , development may begin . Pick up hangers as shown , and lower into developer tank . It is advisable to practice this in light .
Fig . 24 Larger film hangers are more easily handled in specially built racks . Practice placing hangers in the rack before trying to do it in the dark .
Fig . 25 For agitation , lift rack entirely out of the solution . Drain as shown for one second and lower again into the solution .
will flow uniformly around the film rather than violently through the hangers and will set up no regular flow pattern .
4. When development is complete , transfer the films as a unit to the rinse bath . Lift and drain two or three times , and transfer to the fixing bath . Agitate again several times and then allow them to fix undisturbed , although if you are in a hurry , you can reduce fixing time slightly by constant agitation .
5. After fixing , transfer the films to the washer for a 30 minute wash in running water . After washing , the films may be swabbed to remove excess water or given a short rinse in a wetting agent , as has been described for roll film processing . They are then hung up to dry .
It is common practice to dry sheet film in their hangers , but it is generally better practice , at least in the larger sizes , to remove the films from their hangers and hang them on the film clips where they can dry more quickly and uniformly . This is shown in Figure 26 .
Fig . 26 After a final rinse in a wetting agent , the film is ready for drying . It is best to hang the film as shown .
In this part of the Assignment , we have discussed the general procedures used in the development of roll and sheet film . We have given you the principle reasons for each step taken and have pointed out some of the pitfalls to be avoided . If you follow the instructions given here , you should be able to develop your exposed film properly and get good results . Most photographers never get beyond this point . As a student of photography , however , you should have a much fuller understanding of these basic procedures so that you will not follow them slavishly when conditions change or photographic materials are improved .
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