5
The step wedge is positioned and printed on the film as
follows:
The slides in the magazines of the Wild RC-8 cameras
extend about one inch under a lip at the forward end of the
magazines when in a fully closed position. These slides can
be withdrawn as much as V2 inch from the fully closed posi
tion, by manually releasing the locking button, without
permitting any light to fog the film.
We marked our slides at this V2 inch position and drilled
a 1/32 inch hole in each slide at the position shown in figure
18. The photographer withdraws the slide slightly, inserts a
needle through the 1/32 inch hole, and makes a punch mark
on the film to guide the laboratory technician who must
work in total darkness. The 1/32 inch hole is positioned so
that the photographer need withdraw the slide only about
1/8 inch for this operation. This hole permits no light to
enter the magazine when the slide is fully closed and the
small amount of light that enters during the punching of
the film does not affect the subsequent printing of the step
wedges.
The photographer leaves two blanks at the beginning
of the roll and punches the needle hole after the second
blank has been wound through. Since the needle hole is at
the forward corner of the magazine, this positions the
punched hole between the two blanks.
One blank is left at the end of photography on each
roll and a punch mark is made at the end of this blank.
Two blanks are also left as near the center of the roll
as possible without breaking a flight line, and a hole is
punched between these blanks. Thus, unexposed film is left
at the center and both ends of each roll for the introduction
of the step wedge and each of these unexposed sections of
film is marked with a punched hole.
The sensitometric strips are exposed on the film in the
laboratory, in total darkness, at the places indicated by the
punch marks (Figure 19). The film is then processed in the
normal manner using a wind-rewind system (Figure 17). An
analysis is made from the sensitometric strips immediately
after processing to detect: exposure errors, processing errors
due to chemistry or chemistry break down, color shifts
inherent in the film emulsions or other faults in manufac
turing, and to obtain information as to densities resulting
from the wind rewind method at the middle and ends of
the strip.
The color film is processed at 75° F using Anscochrome 80°
chemistry for Anscochrome FPC-289 film and Kodak 75°,
E2-E3 chemistry for the Kodak MS Ektachrome film (Fig. 17).
The agitation provided by the wind-rewind method eliminates
the need for an additional nitrogen-burst agitation system.
The chemical treatments and flow diagrams are shown in tables
2 and 3.
Recommended pH levels and permissible tolerances for each
step are shown in Tables 4 and 5.
A departure from these levels may be necessary because
of the chemical composition of local water sources. We have
found that the use of a forced-air-type film dryer without heat,
and a dilution of the final rinse solution in the dewind tank to
six parts of water to one part of rinse chemical, permits a re
duction in the number of required tanks. The rinse solution also
functions as the final wetting agent in the process.
SUGGESTED PROCESSING TIME AND
TEMPERATURE TABLE FOR ANSCHROME
TYPE FILMS
Solution Temperature 100 ft.
TOTAL DARKNESS
1)
Pre bath
75F ±
2F
6
2)
First Developer
75F ±
iF
12
3)
Short stop hardener
75F ±
2F
5
Wash in running water
70F —
75F
20
Second exposure—Two complete
cycles
with
a No. 2 photoflood 3 ft. from
each side of the film
Note: Handle the wet film carefully so that no
water will splatter on the hot lamp causing
it to shatter.
ROOM LIGHT
Color Developer
75F ±
*F
32
Short stop hardener
75F +
2F
5
Wash in running water
70F —
75F
20
Bleach
75F ±
2F
11
Wash in running water
70F —
75F
10
Fixer
75F ±
2F
6
Wash in running water
70F —
75F
15
Stabilizer
75F ±
2F
6
Wash in running water
70F —
75F
3
Final rinse
75F ±
2F
2
Note: Wash times for this process
have been
calculated on the
basis of a 2|
gallon
/minute flow. If
the water flow
is less
than this wash times should be increased.
TABLE 2
Summary of steps for
KODAK EKTACHROME FILM PROCESS E-3
Agitation: See instructions and follow them carefully.
Timing: Include drain time (10 seconds) in time for each processing step.
Solution or
Procedure
Remarks
Temp
(F)
Time
in Min
Total Min
at end
of Step
1. First
Developer
75±|
10
10
2. Rinse
Running water
73—77
1
11
3. Hardener
73—77
3
14
Remaining steps can be done in normal room light.
4. Wash
Running water
73—77
3
17
5. Reversal
Exposure
Re-expose as prescribed for equipment used.
Films must receive at least 1-minute drain
before color development.
Reset
Timer
to Zero
6. Color
Developer
73—77
15
15
7. Wash
Running water
73—77
5
20
8. Clearing
Bath
73—77
5
25
9. Rinse
Running water
73—77
1
26
10. Bleach
See warning on label.
73—77
8
34
11. Rinse
Running water
73—77
1
35
12. Fixing Bath
73—77
6
41
13. Wash
Running water
73—77
8
49
14. Stabilizer
See warning on label.
73—77
1
50
15. Dry
Remove sheet films from hang
ers and roll films from reels.
Not over
110
TABLE 3