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الخطوة 1: التحكم في السلبيات / المطورين .. تقنيات الغرف المظلمة المتقدمة .. المرشد خطوة بخطوة للتصوير الفوتوغرافي
STEP 1 : CONTROLLING THE NEGATIVE / Developers
For most films you can use a general purpose or " universal " developer . But other types of developer are available which enable you to alter the grain , or contrast on the final negative , or increase the film's sensitivity .
All developers should be matched with the appropriate film type . High acutance developers , which resolve fine detail on the negative , work best with slow films ( under about 50 ASA ) . Fine grain developers help to minimize the graininess of medium or fast films ( between 50 and 800 ASA ) . Speed enhancing developers which have the effect of increasing the sensitivity ( speed ) of the film can compensate for underexposure , and work best with films of 400 ASA or more .
Black and white film structure
Gelatin supercoat
Emulsion
Film base
Anti - curl layer
A clear gelatin top coat helps to protect the sensitive emulsion from abrasion . Light - sensitive silver halides in the emulsion layer are either fine and thinly coated ( slow film ) or are relatively coarse and thickly coated ( fast film ) . The emul- sion layer is supported by a plastic , or triacetate , base . Beneath it , another gelatin layer inhibits curling and contains a gray antihalation dye that prevents any light reflect- ing back into the upper layers .
Matching film and developer
Slow film ( 32 ASA )
Universal developer
The negative , left , was processed in general , or universal , developer . Because the film is slow there is good detail on the image .
The area of the negative shown on this page is magnified 28 times .
Slow film ( 32 ASA )
High acutance developer
The negative , left , was taken on the same slow film but processed in a high acutance developer ( Acu- special FX - 21 ) . The developer has sharpened local contrast so that detail is brought out further . High acutance developers work best with slow films .
Fast film ( 400 ASA )
Universal developer
The negative , left , was taken on a fairly fast , 400 ASA film and processed in the same general developer as the slow film above . But because this film is ten times faster than the slow film , coarse grain is clearly visible on the processed negative .
Fast film ( 400 ASA )
Fine grain developer
The negative , left , on the same fast speed film , was processed in a fine grain developer ( D.76 ) . This has reduced the graininess on the negative by inhibiting the clumping together of the black silver gains during development .
Ultra fast film ( 1250 ASA )
Normal developer
Universal developer , used for the two films above , would cause stain- ing and fogging if used with the coarse grained emulsion of this ultra fast film . The recommended normal developer ( DK - 50 ) was used instead . The detail is broken up on the negative by graininess , left .
Ultra fast film ( 1250 ASA )
Speed enhancing developer
Processing with Acuspeed or a similar speed enhancing developer greatly compensates for under- exposure as shown in the negative . exposed as if 3000 ASA , left . Speed enhancing developers increase the speed of your film by up to 24 times , enabling you to take pic- tures in extremely low lighting you know you are going to use such a developer you can uprate the film in the camera by the amount recommended by the developer manufacturers .
STEP 1 : CONTROLLING THE NEGATIVE / Developers
For most films you can use a general purpose or " universal " developer . But other types of developer are available which enable you to alter the grain , or contrast on the final negative , or increase the film's sensitivity .
All developers should be matched with the appropriate film type . High acutance developers , which resolve fine detail on the negative , work best with slow films ( under about 50 ASA ) . Fine grain developers help to minimize the graininess of medium or fast films ( between 50 and 800 ASA ) . Speed enhancing developers which have the effect of increasing the sensitivity ( speed ) of the film can compensate for underexposure , and work best with films of 400 ASA or more .
Black and white film structure
Gelatin supercoat
Emulsion
Film base
Anti - curl layer
A clear gelatin top coat helps to protect the sensitive emulsion from abrasion . Light - sensitive silver halides in the emulsion layer are either fine and thinly coated ( slow film ) or are relatively coarse and thickly coated ( fast film ) . The emul- sion layer is supported by a plastic , or triacetate , base . Beneath it , another gelatin layer inhibits curling and contains a gray antihalation dye that prevents any light reflect- ing back into the upper layers .
Matching film and developer
Slow film ( 32 ASA )
Universal developer
The negative , left , was processed in general , or universal , developer . Because the film is slow there is good detail on the image .
The area of the negative shown on this page is magnified 28 times .
Slow film ( 32 ASA )
High acutance developer
The negative , left , was taken on the same slow film but processed in a high acutance developer ( Acu- special FX - 21 ) . The developer has sharpened local contrast so that detail is brought out further . High acutance developers work best with slow films .
Fast film ( 400 ASA )
Universal developer
The negative , left , was taken on a fairly fast , 400 ASA film and processed in the same general developer as the slow film above . But because this film is ten times faster than the slow film , coarse grain is clearly visible on the processed negative .
Fast film ( 400 ASA )
Fine grain developer
The negative , left , on the same fast speed film , was processed in a fine grain developer ( D.76 ) . This has reduced the graininess on the negative by inhibiting the clumping together of the black silver gains during development .
Ultra fast film ( 1250 ASA )
Normal developer
Universal developer , used for the two films above , would cause stain- ing and fogging if used with the coarse grained emulsion of this ultra fast film . The recommended normal developer ( DK - 50 ) was used instead . The detail is broken up on the negative by graininess , left .
Ultra fast film ( 1250 ASA )
Speed enhancing developer
Processing with Acuspeed or a similar speed enhancing developer greatly compensates for under- exposure as shown in the negative . exposed as if 3000 ASA , left . Speed enhancing developers increase the speed of your film by up to 24 times , enabling you to take pic- tures in extremely low lighting you know you are going to use such a developer you can uprate the film in the camera by the amount recommended by the developer manufacturers .
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