Basic Photography Course

Figure 10-21.Roller transport processor.

operation, and maintenance instructions supplied with
it. Therefore, in this section only general information
that applies basically to any machine processor is
discussed.

TRANSPORT SPEED

Most black-and-white automatic film processors

have a variable speed operation. Unlike hand processing
where developing time is measured in minutes and
seconds, machine processing developing times are
measured in feet-per-minute (fpm). Both methods
measure the length of time the material is affected by
the developer and other solutions. Most color processors
have a set machine speed that can only be adjusted
slightly because color materials must be processed to
specific parameters so processing cannot be manipu-

lated.

The time the solutions are allowed to act on the film

or paper is a result of the speed that the machine moves
the sensitized material and the length of time the
material is immersed in a particular tank. Most machines
have an fpm indicator that shows the set speed of the
processor. The temperatures of solutions and the
specific number of feet in each section of the machine
are usually constant factors. It is the rate the paper or
film travels that determines the total processing time; for
example, if the speed is set to 10 fpm and the total roller

path in the developing tank is 30 feet, a certain point on
the material being developed takes 3 minutes (30

10).

Regardless of the machine speed, film or paper

cannot be processed faster than the total required
solution times. For example, you are processing film
that requires a processing and drying time of 10 minutes
and 20 seconds. When the machine is processing this
film, it takes 10 minutes and 20 seconds before the first
foot of film leaves the dryer. However, the total time to
process the entire roll is related to the speed of the
machine and the total length of the material. For
example, if the machine speed is 10 fpm and the roll is

10 feet long, the film takes 10 minutes, 20 seconds, plus
1 minute (10

10). With a 200-foot roll, access time is

10 minutes, plus 20 seconds, plus 20 minutes

(200

10), or a total of 30 minutes, 20 seconds. It is

important for you to know the access time of the
processor. When the material being processed does not
exit the machine in the required time, a machine
malfunction or jam is evident.

WATER TEMPERATURE AND FLOW RATE

Wash water is an important processing con-

sideration. Not only is the water temperature important
but also the flow rate of the water. Two factors that must
be considered are as follows: sufficient flow to ensure

10-29

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Basic Photography Course

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DOFMaster for Windows On-line Depth of Field Calculator DOFMaster for Mobile Devices On-line Depth of Field Table Hyperfocal Distance Chart Articles FAQ Recommended Books Support Contact Links Home As an Amazon Associate I earn from qualifying purchases.	contents <- previous page next page -> Figure 10-21.Roller transport processor. operation, and maintenance instructions supplied with it. Therefore, in this section only general information that applies basically to any machine processor is discussed. TRANSPORT SPEED Most black-and-white automatic film processors have a variable speed operation. Unlike hand processing where developing time is measured in minutes and seconds, machine processing developing times are measured in feet-per-minute (fpm). Both methods measure the length of time the material is affected by the developer and other solutions. Most color processors have a set machine speed that can only be adjusted slightly because color materials must be processed to specific parameters so processing cannot be manipu- lated. The time the solutions are allowed to act on the film or paper is a result of the speed that the machine moves the sensitized material and the length of time the material is immersed in a particular tank. Most machines have an fpm indicator that shows the set speed of the processor. The temperatures of solutions and the specific number of feet in each section of the machine are usually constant factors. It is the rate the paper or film travels that determines the total processing time; for example, if the speed is set to 10 fpm and the total roller path in the developing tank is 30 feet, a certain point on the material being developed takes 3 minutes (30 ÷ 10). Regardless of the machine speed, film or paper cannot be processed faster than the total required solution times. For example, you are processing film that requires a processing and drying time of 10 minutes and 20 seconds. When the machine is processing this film, it takes 10 minutes and 20 seconds before the first foot of film leaves the dryer. However, the total time to process the entire roll is related to the speed of the machine and the total length of the material. For example, if the machine speed is 10 fpm and the roll is 10 feet long, the film takes 10 minutes, 20 seconds, plus 1 minute (10 ÷ 10). With a 200-foot roll, access time is 10 minutes, plus 20 seconds, plus 20 minutes (200 ÷ 10), or a total of 30 minutes, 20 seconds. It is important for you to know the access time of the processor. When the material being processed does not exit the machine in the required time, a machine malfunction or jam is evident. WATER TEMPERATURE AND FLOW RATE Wash water is an important processing con- sideration. Not only is the water temperature important but also the flow rate of the water. Two factors that must be considered are as follows: sufficient flow to ensure 10-29 contents Basic Photography Course <- previous page next page ->	As an Amazon Associate I earn from qualifying purchases.
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