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KODAK PROFESSIONAL ULTRA III Paper • E-142 3
6. Adjust the exposure for the new filter pack. An exposure
time that produced a print of satisfactory density may
not produce an acceptable density when you change the
filter pack. The following table gives filter factors for
calculating exposure adjustments when you use
KODAK CP or CC Filters.
To use the factors, divide the old exposure time by the
factor for any filter you remove. If you add a filter, multiply
the time by the factor. If you add or remove two or more
filters, multiply the individual factors and use the result as
your factor. You may need to modify these factors for your
equipment.
Note: The filter factors listed in the table take into account
the effects of filter surfaces.
When you adjust the filtration in equipment that has
built-in dichroic filters, any noticeable differences in density
are due to differences in the color density of the print.
Suppose you have a print with acceptable density, but a
magenta balance. When you add magenta filtration to correct
the color balance, the print will become too light, so you
must use a longer exposure time.
A rule of thumb for magenta dichroic filtration is to
change the exposure time by one percent for every unit of
change in filtration. For example, if you increase the
magenta filtration by 20M, increase the exposure time by
20 percent. Changes in yellow dichroic filtration do not
usually affect the apparent print density. If you use cyan
dichroic filtration, use the filter factors in the table above as
starting points for adjusting exposure.
Filter Factors for CP Filters
Filter Factor Filter Factor
05Y 1.1 05R 1.2
10Y 1.1 10R 1.3
20Y 1.1 20R 1.5
30Y 1.1 30R 1.7
40Y 1.1 40R 1.9
50Y 1.1 50R 2.2
05M 1.2 05G 1.1
10M 1.3 10G 1.2
20M 1.5 20G 1.3
30M 1.7 30G 1.4
40M 1.9 40G 1.5
50M 2.1 50G 1.7
05C 1.1 05B 1.1
10C 1.2 10B 1.3
20C 1.3 20B 1.6
30C 1.4 30B 2.0
40C 1.5 40B 2.4
50C 1.6 50B 2.9
Tricolor Exposure Method
Use KODAK WRATTEN Gelatin Filters No. 25 (red),
No. 99 (green), and No. 47B (blue) to give the paper three
separate exposures. Do not move the paper or the enlarger
until you have made all three exposures. Typical exposure
times for making an enlargement from a normally exposed
negative are given in the table below.
Evaluate the test print under light of the same color and
brightness that you will use to display the final print. (See
“Viewing”.)
Judge the print density first. If necessary, make another
print by adjusting the exposure as recommended in the table
below.
Then judge color balance.
Filter
Times for an Aperture Setting of f/8
*
for PROFESSIONAL ULTRA III Paper
(6X Enlargement of a KODAK VERICOLOR III
Professional Film Negative)
* For an enlarger equipped with a Photo Enlarger Lamp No. 212 or
No. 302; the setting may vary with other types of lamps.
Red 3 seconds
Green 21.8 seconds
Blue 17.5 seconds
If y o ur p ri nt i s Do t hi s O R Do this
TOO LIGHT
Open the lens
aperture to
increase the light
level
Increase all
exposure times
proportionately
TOO DARK
Close the lens
aperture to
decrease the
light level
Decrease all
exposure times
proportionately
If your
print is
Subtract time
from the
exposure
through
these filters
OR
Add time to the
exposure
through
these filters
CYAN Red Blue + Green
MAGENTA Green Red + Blue
YELLOW Blue Red + Green
RED Blue + Green Red
GREEN Red + Blue Green
BLUE Red + Green Blue