Light meters
Eastman Kodak Color Temperature Meter User manual
User manual for Eastman Kodak Color Temperature Meter. 16 pages in English. Read the original PDF, download or print a copy without registration.
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- Brand
- Kodak
- Model / document
- Eastman Kodak Color Temperature Meter
- Document type
- User manual
- Language
- English
- Pages
- 16
- File size
- 1.4 MB
- Category
- Light meters
- Document date
- Not specified in catalog
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,{
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such as the top of a radiator, or in a hot sholv
case or window, because the color wedge inside
the meter will be damaged by temperatures
higher than r lB" F. The instrument should be
accorded the same care given to Wratten
Light Filters.
meter has been excessive' subjected If the to ''.'+ The Eastman heat, for or is if its accuracy in doubt ,soine
other reason, it may be sent to the .Eastman
Kodak. Company with a letter pf explanation.
To make sure that the metef and .letter arrive together, fasten the letter secyrely tb the outside r Color Temperafure
of the' package. Put a three-cent stamp on l,t,
the'letter in addition to the postage on the It
pa'ikage, and put the:/eturn uidr..J on boih. F If a qheck shorvs that adjustments or replace- Meter
ment parts are necessary, a reasonable charge
will be rpade. When requested, an estimate of
the charge will be sent to the owner for
confirmation. EASTMA N KODAK COMPANY
Eastman Kodak Company . Rochester 1,, N. Y. ROCHESTER, N. Y.
I-4!'-CH-A PRINTED IN THE UNITED STATES OF AMERICA.View original page 1Page 3 · Read text
7
character. The Color Temferature Meter will
enable the photographer to check his lamps for
their color. If the readings show them to be
is bU* different from that color for which the film /J,* balanced, steps can be taken to compensate
THE EASTMAN for this difference. I It is well known thal the appearance of a
COTOR TEMPER.ATURE colored object differs according to the kind of
light by which it is viewed. For instance, the
METE R difference between daylight and artificial light
in their effect on the apparent color of a piece
of cloth is so marked that it is customary to use
special daylight lamps in examining cloth.
The Eastman Color Temperature Meter is There are, however, differences between lamps
designed to enable the color photographer to which are more or less of the same kind, the
measure the color quality of his illumination. It extent of which depends on their type and
is important to be able to do this, because color wattage, their age, and the voltage at which
films, such as Kodachrome Film, are made to they are operated. These differences cannot
the eye, because the eye give correct color rendering for a definite color *1 always be detected by
of light. If the illumination is not of the quality has the power of compensating for them, and
for which the film is balanced, the finished hence the lamps may all look equally white. possess this power of picture rvill be too warm or too cold in general Color films do not
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compensation, and if the color of one lamp increased by raising the voltage, the light be-
differs from that of another as a result of one of comes whiter, and the color temperature of the
the causes mentioned, the difference rnay lamp increases. The color temperature is not
readily show up in the film, even though the quite the same as the actual temperature of the
eye does not detect it. filament, but as the one increases, so does the
other. In defining color temperature, theCOLOR TEMPERATURE scientist takes as his standard a perfect source
The color quality of a lamp or other source of of radiation. The spectral distribution of this is
light is conveniently described by its "color precisely defined by its temperature. If the
temperature." The effect of temperature on the radiant energy from a lamp has the same visual
color of a hot object is familiar to everybody. color as that of a perfect source, the lamp is said
For instance, if a poker is put in a fire, as it to operate at a color temperature which is the
becomes hotter, its color will first be dull red, same as the actual temperature of the perfect
then bright red, then yellowish white, and if it radiator of energy. A precise knowledge of the
melts, the iron will be definitely white in color. physics involved is not necessary for the success-
Similarly, in the case of an ordinary electric ful application of color temperature values in
Iamp, if the voltage is much below that for practical photography.
which the lamp was made, the light will be Color temperatures are denoted in degrees
yellowish, while if the voltage is raised above Kelvin ('K). They are 273" higher than the
the rated value, the light will become bluish same temperatures on the Centigrade scale. For
white, and eventually the filament will melt. instance, a temperature of 3,ooooC is the same
As the actual temDerature of the filament is as 3,273"K.
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The following table shows the approximate approximate guide. The actual values obtained
color temperatures of some common light in practice will depend on the age of the lamp,
sources: voltage, and other conditions of operation. The
Golor Temperature of Various Light Sources* nature of the reflectors and diffusers employed
Source Color Temperature, oK can exert a marked influence on the effective
6o-watt gas-filled tungsten filament lamp. . z,Bo5 color temperature of the illumination. Values of
I oo-watt gas-filled tungsten filament lamp. . z,B7o color temperature can only be applied strictly
5oo-watt gas-filled tungsten filament lamp. . e,96o to sources having an energy distribution re-
r,ooo-watt gas-filled tungste n filament lamp 3,ozo sembling that of a perfect radiator. Tungstensoo-watt projection lamp. . . 3,175G. E. Mazda 3zoo"I( Lamps ... . . 3,2oo filament lamps fall closely enough in this class.MazdaCPlamps ...3,350 Some arc lamps, and other sources having
25o-watt Photoflood Lamp, No. r. 3,4oo discontinuous spectra are said to have equiualent
soo-watt Photoflood Lamp, No. z . . 3,4oo color temperatures, provided their color matchesr,ooo-watt Photoflood Lamp, No.4...... 3,4oo lamps,SM Photoflash Lamp 3,3oo that of a perfect radiator. Discharge
Photoflash Lamps Nos. 5, I r ) 22) and 5o. . . . 3,Boo such as mercury, neon, and sodium tubes,
Photoflash Lamps Nos. 58 and 2rB..... .. 6,3oo which have characteristic line spectra, cannot
Whiteflame carbonarc... ..5,ooo be said to have color temperatures.Mean noon sunlight at Washington, D.C. . . 5,4ooHighintensitysunarc... ...5,5oo The color temperature of a studio lamp varies
is*The values given in the table, except the last markedly with the voltage at which it
three, were supplied by the General Electric operated. As an approximate rule, it may be
Company, Cleveland, Ohio. taken that the color temperature changes about
The values in the table may be taken as an rooK for each chanse of one volt.
6.View original page 5Page 6 · Read text
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If these differences in color temperature areNEED FOR COLOR TEMPERATURE big enough, they will produce changes in theMEASUREMENT IN PHOTOGRAPHY color balance of the finished picture. If the
Kodachrome Professional Film, Type B, is lamps are operated at color temperatures below
made to give correct color rendering when { 3,2oooK, the picture will appear warm in hue,exposed to light at a color temperature of ' while if they are run at higher values, the
3,2oooK. This value was selected as represent- results will be bluish, or cold in color.
ing the average quality of light in general use in i The arguments which apply to Kodachromecommercial and professional studios. In prac- i Professional Film, Type B, are applicable also
three-color one-tice, it is found that the line voltage may vary I to other color films, and to exposure cameras, if they are designed to giveover a wide range. Although the electricity l--supply companies endeavor to maintain the balance at a definite color temperature.
line voltage constant, there are times of the day Kodachrome Professional Film, Daylight
awhen the load is extremely high, or very low, I Type, is balanced to give correct rendering at temperature somewhat higher than thatand the actual voltage delivered will vary i coloraccordingly. Ttris will produce corresponding of average noon sunlight. Daylight varies con-
changes in the color temperature of the light siderably in its effective color temperature,
from the lamps. Similarly, lamps may be of according to the latitude, time of day, condi-
various ages, and it is found that there may be a ;-, tion of the sky, and so on. It is less amenable to
color temperature difference of several hundred compensation than artificial light, but the
degrees between a new lamp and the same type I principles to be described for artificial light may
taken to apply in general to daylight.of lamp when it is about to be discarded. . b.
8 9View original page 6Page 7 · Read text
Kodachrome Film, Type A, for miniature made with the knowledge that the results will
cameras, is balanced for use with Photoflood be satisfactory as far as the color quality of the
Lamps, which operate at a color temperature actual illumination is concerned.
of 3,4oo'K. Kodachrome Professional Film, The Color Temperature Meter is not an ex-
Type B, exposed to these lamps, will be some- posure meter; it tells nothing about the bright-what blue in color, while if Kodachrome Film, t ness level of the illumination.
Type A, is exposed to lamps operated at i If the meter indicates a color temperature
3,2oooK, it will be yellowish in color. appreciably different from that for which the
In practice, it is found that a color tempera- I film is balanced, appropriate adjustment must
ture difference of about roooK can be picked be made. There are two methods by which this
up on Kodachrome Film. signed by mike butkus compensation can be effected:
cn=mike butkus, mike DigitallyDN:o=orphancameras, ou=29,
email=mike@butkus.org, c=US In the first method, which is to be preferred,
Date: 2019.09.01 17:10:34USE OF THE EASTMAN GOLOR butkus -04'00' the voltage across the lamps is adjusted untilTEMPERATURE METER the correct color temperature is attained. This
The Color Temperarure Meter is intended to can be done by the use of voltage control units,
permit control of the quality of the illumination such as rheostats, or by other appropriate
so that proper color balance is obtained in the means usually available to photographers hav-
final color photograph. It gives a direct measure ing their own generators. Provided the studio
of the color temperature of the light falling on lamps do not differ too widely in wattage, zge,
the subject. If the readings are correctly made, and type, and the voltage drop is roughly equal
and this temperature is the same as that for in all leads, it is sufficient to vary the voltage by
which the film is balanced, the exposure may be a rheostat at the switchboard. In rare cases. it
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may be necessary to have individual rheostats toward the face and pointed at a lamp of
in the lines to the lamps. moderate wattage so that the field seen through
In the second method, which should be used the eyepiece is at its brightest. The field will be
in studios where voltage control is not possible, seen to be circular, and divided by a vertical
special compensating filters must be used over line. The part to the right of the line appears
the camera lens. For this purpose, a series of yellow, and that to the left will be red or green,
Eastman Color Compensating Filters has been depending on the color temperature of the
designed. www.butkus.us Iamp and the position of the dial on the instru-
ment. The eyepiece should be rotated until the
OPERATION OF THE EASTMAN dividing line is in sharp focus. With the meter
COLOR TEMPERATURE METER still pointed at the lamp, rotate the knob until
The box containing the Eastman Color both halves of the field appear yellow and
Temperature Meter and its case includes also match in color; then if the knob is rotated in
the following items: one direction, one half of the field will gradually
become green in color, or if it is turned in the One special candle, which burns with known opposite direction, the same part of the field spectral distribution. will graduaily become red. Between these two
One Accommodation Adjustment Filter. positions at the point where both halves of the
Six sheets of white Eastman Color Tempera- field are yellow and match in color and bright-
ture Test Paper. ness, the index line on the body of the meter
In order to familiarize the user with its oper- points to the color temperature of the lamp
ation, the meter should be held with the knob indicated on the movable scale. The operation
t2 l3View original page 8Page 9 · Read text
should be repeated a number of times, and the Above 6,000o, the scale closes in, and the
readings averaged. divisions represent progressively greater steps,
It may be found that the readings obtained as will be evident from inspection of the scale.
differ somewhat from each other. This is be- When the line on the body is between two
cause many people find it difficult at first to divisions on the scale, the actual reading must
obtain consistent matching. Some practice will, be found by interpolation.in general, be necessary for the user to obtain f In reading the instrument, it is always good
the consistent results required. This is common practice to make a number of determinations,in all optical instruments which employ photo- ! say at least five, and take the average. With
metric matching fields to make readings. experience, it is possible to read the color
In order that the figures on the dial may be temperature of studio lamps to an accuracy of
printed to a fairly large size, they are abbrevi- less than fifty degrees, which is amply high for
ated by omission of the final two zeros. Thus a practical use, since a difference of this value
dial reading of zB represents a color tempera- cannot be detected in the color of the picture.
ture of 2,Boo"; one of 34, a temperature of SETTING THE ACCOMMODATION SCALE3,4oo", and so on. The scale is so divided that
up to a color temperature of 4,oooo, the main The use of the instrument presupposes normal
divisions represent intervals of 2oo" and the color vision. Color-blind people will not be able to
subdivisions steps of 5o'. From 4,oooo to 6,oooo, use the meter, and neither will those rulto haue certain
abnormalities in their color aision There is muchthe main divisions are at intervals of 5oo' and I
the subdivisions are steps of roo" from 4,oooo to difference in the color accommodation between
the5,oooo, and of z5oo from 5roooo to 6roooo. J different people, and sometimes between
74 t5View original page 9Page 10 · Read text
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two eyes of the same person. It is, therefore, filter mount. The candle sh<-ruld be lighted and
necessary to set each instrument for the individ- set up in a dark place free from drafts. Hold the
ual eye before putting the meter into use. Once filter over the objective of the meter, and sight
this has been done, the meter will be satisfactory on the candle flame through it, so that the field
I for that individual, and will not have to be re- is at its brightest all over. About four inches
adjusted unless the setting is changed for some + distance is sufficient. First set the color tempera-
reason. If the instrument is used by several ture scale to the temperature indicated on the
people, each will have to set the accommoda- 'l filter mount. Hold the meter in the left hand,
tion scale to suit himself. I and with the thumb, press down firmly on the
The most desirable way of setting the scale is temperature scale to hold it in a fixed position
to employ a standard lamp, operated at a as the knob is rotated. Now sight on the candle
known color temperature. Such sources are not flame, holding the Accommodation Adjustment
readily available to most photographers, but Filter over the objective of the meter with the
are to be found in many electrical testing or first and second fingers of the left hand, and
optical laboratories. In order to permit the pho- obtain the best possible color match by rotating
tographer to effect the calibration himself, the the knob alone. This will give a setring of the
special candle and blue Accommodation Ad- accommodation scale at the base of the knob.
justment Filter are provided. The adjustment is Several readings should be taken until consist-
made in the following manner: ent values are obtained, say within one small
When viewed through the blue filter, the division on the accommodation scale; this will
flame of the lighted candle has an effective give the proper personal accommodation factor.
color temperature equal to that marked on the This setting should be used with this particular
76 '77View original page 10Page 11 · Read text
meter. Conditions of fatigue and eye strain provided with the meter. Hold a sheet of this
make it important that the accommodation special paper in the full beam of the light and
setting be redetermined occasionally. then direct the Color Temperature Meter
The candle should be burned for a minute or toward it, and read the reflected light. The
two before a reading is made, to enable the white paper supplied for this purpose is so
flame to come to temperature equilibrium. The *, chosen that the color quality of the light re-
top of the candle should contain a full puddle of flected from it differs only slightly from the
wax. If a glowing red tip forms on the end of I color quality of the light falling upon it. When
the wick, the tip should be cut off so that the the paper is used, 75" should be subtracted
wick is about fu inch long. www.butkus.us from the meter reading in order to obtain the
color temperature of the source itself. * Ordinary
READING THE COLOR TEMPERATURE white paper and other white objects uill by no means
In order to read the color temperature of a be satisfactor2 for this purpose.
lamp, it is only necessary to point the meter in The Eastman Color Temperature Test Paper
the direction of the lamp so that the fieid is at can be used to measure the color temperature
its brightest, and turn the knob until a color of individual lamps or it can be placed on the
match is obtained. The lamp itself will not be *The value 75' applies only to color tempera-visible in the meter. In measuring the color tures about 3,ooooK. The actual deduction to be
temperature of very strong light sources such as made will depend on the color temperature indi-
studio lamps, the field may be too bright to cated by the meter. At about 4,ooooK the deduc- tion will be r3oo; at about 5,ooooK the deductionpermit an accurate reading. For this purpose will be 2oo". Deductions for intermediate color
the Eastman Color Temperature f-est Paper is temperatures should be roughly proportional.
18 l9View original page 11Page 12 · Read text
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scene to be photographed in order to measure changed so that the color temperature is
the color temperature of the entire illumination. correct for the film, or one of the Eastman
When placed on the colored set, it should be Color Compensating Filters should be used.
placed in such a position that no light re-
flected from a strongly colored object in the USE OF THE EASTMAN COLOR
COMPENSATING FILTERS set falls upon it; this would cause incorrect it
readings to be obtained. If there is a bright The Eastman Color Compensating Filters
light or strongly illuminated colored subject have been designed to allow the photographer behind the white paper, light may be trans- I to adjust the quality of his lights to rhe correct
mitted by the paper and so affect the reading value for proper color rendering. These filters
obtained. In such circumstances, the white are supplied in sets of seven: four bluish and
paper should be backed by a piece of photo- three yellowish. They are designated by the
graphic black paper. letters CC. Filters CC3 to CC6 are bluish, and
Important: When a sheet of test paper shows CCr3 to CCr5 are yellowish in color. The
any discoloration, or if it should be soiled, it bluish filters are for the purpose of raising the
must be discarded and a new sheet used. effective color temperature when the quality of
In using Kodachrome Professional Film, light emitted is somewhat lower than that from
Typ. B, if the color temperature of the illumina- a source operating at 3,2oooK, and the yellowish
tion is found to be appreciably different from filters are for lowering the effective temperature
3,zoooK, that is, more than roo' higher or of lamps operating higher than 3,eoo'K.lower, it is necessary to introduce compensa- To select the proper filter for Kodachrome
tion. Either the voltage of the lamps must be Professional Film, Typ. B, set the scale of the
20 2tView original page 12Page 13 · Read text
Color Temperature Meter at 3,eoooK and test films balanced for other color temperatures are
the quality of illumination on the set. If the used, such as Kodachrome Film, Typ. A. The
field of the meter is not in color balance, filters can also be used to give some correction
maintain the 3,zoooK setting and select from the for variations in daylight in the use of Koda-
set of compensators by trial and error the filter chrome Professional Film, Daylight Type.which restores the balance when it is held il Note: The Eastman Color Compensating
over the objective of the meter. When the i Filters are not calibrated with the precision of
temperature is lower than 3,2oooK, a bluish II the filters of the Wratten series. Although every
filter rvill be required. When the temperature is I attempt will be made to maintain them uni- 'formhigher than 3,roooK, z yellowish filter is re- in manufacture, no guarantee can be
quired. The filter which restores the balance in given to match any particular filter with a
the meter is the one which should be used over duplicate. Since the same filter is used over the
Ithe lens of the camera in making an exposure meter and the lens of the camera, and since
in order to produce correct color rendering in I't' filter factors are negligible, there is no need for
the photograph. In some extreme cases it may j strict interchangeability as in the case of
I Wratten Filters.be necessary to combine two or more of the
compensating filters to secure correct exposure
conditions. This procedure is not recommended, VARIATION OF COLOR OF DAYLIGHT
however, except in an emergency. When more t When outdoor Iight conditions are read with
:than one filter is required, the troublesome the Color Temperature Meter it is necessary
lamp should be replaced with a new one. 1 that the test paper be used. It should be held
The same method should be employed when ? to reflect the strongest light toward the meter.
22 23View original page 13Page 14 · Read text
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In balancing Kodachrome Professional Film, tometric series can also be used for correction
Daylight Typ., a color temperature somewhat purposes. No specific recommendations can be
higher than that of mean noon sunlight at made, since conditions vary so much, and often
Washington, D.C. was taken as standard. How- rapidly. The photographer is advised to make
of daylight is extremely variable. the colorever, a basis
madePhotographs on Kodachrome Profes- * fortrialsapplyingto suit thethe particularcompensatingconditions.filters, Ashowever,
sional Film, Daylight Typ., show a predomi- it is suggested that the meter be set at 6,ooo"K.
nance of warm sunlight values if they were t" The Photometric Filters of the 78 Series (see
made early or late in the day, in high latitudes, I? "Wratten Light Filters" book) are bluish in
or in the winter time in moderate latitudes. color, and are for increasing color tempera-
On the other hand, they are frequently bluish ture. They may be useful if the light is pro-
if made in the shade,'or with an overcast sky. nouncedly ),ellow in color. The Photometric
The Eastman Color Temperature Meter can Filters of the 86 series are yellowish in color,
be used to give an approximate measure of the and are for decreasing color temperature, and
departure of the color of daylight from that cor- certain of them should be found useful if the
responding to the color temperature for which light is definitely bluish. These filters are ac-
the film is balanced. The Eastman Color Com- tually made for visual, and not photographic
pensating Filters can be used to effect some correction, but it is possible that adequate
compensation for such departure, but the pos- photographic compensation may be obtained
sible variation in effective color temperature of in extreme cases.
daylight is so wide that these filters may not be Some idea of the possible variation in the
entirely adequate. Wratten Filters of the Pho- effective color temperature of daylight is given
24 25View original page 14Page 16 · Read text
r such as the top of a radiator, or in a hot show www.butkus.us
case or window, because the color wedge inside'
the meter rvill be damaged by temperatures
higher than I rB' F. The instrument should be
accorded the same care given to Wratten
Light Filters.
If the meter has been subjected to exces'sive' '' The Eastman heat, or if its accuracy is in doubt for soirre
other reason, i1 may be sent to tlie .Eastman
Kodak. Company with a letter pf explanation.
To make sure that the meter and letter arrive together, fasten the letter seqylqly tb the outside Color Temperafure
of the package. Put a thr.-ee-cent stamp on
-the'letter in additioe to the posrage on the
package, and put the leturn uad...J on boih. If a check shorvs that adjustments or replace- Meter
ment parts are necessary, a reasonable charge
will be rnade. When requested, an estimate of
the charge will be sent to the owner for
confirrnation. EASTIiAN KODAK COMPANY
ROCHESTER, N. Y. Easffian'Kodak Company . Rochester { N. Y.
I-4s-CH-A PRINTED IN THE UNITED STATES OF AMERICA.View original page 16From the M. Butkus archive. Original publisher and archive notices are retained.
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