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Патент USA US2500049

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March 7, 1950
‘
' F. c. WILLIAMS EIQ‘AL
2,500,049
APPARATUS FOR mans COLOR PRINTS
Filed May 10, 1946'
'
:5 Sheets-Sheet 1
2'.FIG.
FIG.1
5-1
[email protected]
’
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‘
INVENTORS
BY 4am-m
Mm
March 7, 1950
2,500,049
F. c. WILLIAMS ETAL
APPARATUS FOR MAKING COLOR PRINTS
Filed May 10, 1946
3 Sheets-Sheet 2
so:
Eu
0
Wm‘..
mm c. WILLIAMS
FORDYCEM. BROWN
mmwoxs
BY W '
ATTORNEYS
'
March 7, 1950
2,500,049
F. c. WILLIAMS EI'AL
APPARATUS FOR mmc COLOR PRINTS
Filed May 10, 1.946
3 Sheets-Sheet 3
FIG.5.
FIG.4.
FIG.-7.
c
N
FRANKLIN C. WILLIAMS
FORDYCE M. BROWN
INVENTORS
BY
W/
1/
ATTORNEYS
2,500,040
Patented Mar. 7,v 1950
UNITED STATES PATENT OFFICE
2,500,049
APPARATUS FOR
COLOR PRINTS
' Franklin 0. William and Fordyce M. Brown,
Rochester, N. Y., asslgnors to Eastman Kodak ~
/ Company, Rochester, N. Y., a‘ corporation of
New Jerley
Application May 10, 1946, Serial No. 668,832
17 Claims. (01. 88-24)
1
.
The present invention relates to photography,
and particularly to an apparatus for making color
The primary object of the present invention is
the provision of an apparatus for compensating I
prints.
for variations in the exposure requirements in
making a color print by the above-disclosed
method and apparatus which might be intro
duced by a change in the color sensitivity of the
printing material due to an actual change in the
emulsion sensitivity and/or an apparent change
in sensitivity due to a change in the processing
Speci?cally, this invention relates to an im
provement in the method and apparatus for
making color prints set forth in copending patent
applications, Serial Nos. 668,800 and 771,068, ?led
May 10, 1946, and August 28, 1947, respectively,
in the names of C. M. Tuttle and F. M. Brown.
The color printer set forth in these copending
Procedure.
applications, and known as a negative-integrator
And yet another object is to provide an appa
type printer, operates in the following manner:
ratus, hereinafter referred to as a compensating
unit; or compensator, which can be built into,
The color negative is placed over a diffuse light
source. An image of this negative is projected
to form a part of, said color printer so that the
onto a color-sensitive paper by a lens which can 15 printer so equipped will have its control auto:
be successively covered by a red, a green and a
matically compensated for variations in the ex
blue ?lter. Light from this source and trans
' posure requirements introduced by any one or
mitted by the negative also illuminates a photo
all of the changes mentioned.
electric cell in such a way that an integration
Still another object is to provide a compensat
of the negative’s transmittance is effected. When 20 ing unit for a color printer of the negative
the red ?lter is over the projection lens a similar,
integrator type referred to which includes means
but not identical, red ?lter is also placed over
for illuminating each of different color areas of
the integrating cell. With such an arrangement
a compensating chart, made by a given exposure
> the intensity of the source is quickly adjusted
through red, green and blue ?lters on the print
until a predetermined ?xed response of the photo 25 ing material to be used and processed by the pro
electric cell and system associated therewith
cedure to be used, with a light of known intensity
results and a ?xed time exposure is then given
and of a color substantially complementary to
to the printing material. The operation is then
the area of the chart illuminated thereby, and
repeated with green ?lters over, the lens and
photo-electric means measuring the amount of
photo-cell, adjusting to the same photo-cell sys
light re?ected by each area. The photo-electric
tem response, and finally with blue ?lters over
means of the unit is connected to the photo
the lens and photo-cell.
‘
electric integrating cells of the printer control
The adjustments of the printer control (the
system so that the output of the former when
predetermined response of the photo-cell system
measuring the amount of light re?ected by" a
which determines the intensity of the colored 35 chart area when illuminated by a given color
printing beam) are empirically determined. and
light (red) is adapted to change the amount of
are correct only for a given set of color sensitivi
response required of the integrating cells of the
ties of the individual layers of the multi-layer
printer when measuring the intensity of a corre
color sensitive printing material. If a change
sponding color light (red) transmitted by the
in any of these color sensitivities occurs as a re
40
sult of change in printing material or in process
A further object is to provide a compensating
unit of the type described in which the chart
areas, the illuminating means therefor and the
cells for measuring the amount of light reflected
by said areas are so arranged and disposed rela
tive to one another that only the light diffusely
re?ected by said areas is measured by the cells.
And yet another object is to provide a com
60 pensating unit in which the intensity of each of
ing, the adjustments of the printer control must
be revised.
This means that every time a new
batch of printing material is used which might
have a color sensitivity different from that for
which the printer is initially adjusted, or there
is a change in the processing procedure (such
as a change in processing solutions, the order of
processing, etc.) which might cause a change in
the apparent color sensitivity of the printing
material, the printer must be readjusted ‘em
pirically to accommodate any change in sensi
tivity which might occur. This is a decided
drawback which restricts the quality and the
negative.
'
. the chart area illuminating beams may be ad
justed simultaneously by the same amount to
vary the over-all density of a color print, or the
intensity of the illuminating means for the re
quantity of the output of the printer in question. I‘ spective chart areas can be individually adjusted
0,500,040
hated. shows identical yellow and magenta dye
for the purpose of altering the color balance of
a color print made on the printer.
deposit densities, but an increase of 0.10 in den
sity of the cyan deposit. The required revision
of printer adjustment is one which will decrease
the printing of the red sensitive layer of the
The novel features that we consider charac
teristic of our invention are set forth with par
ticularity in the appended claims. The invention
itself, however, both as to its organization and
its methods of operation, together with additional
objects and advantages thereof, will best be un
derstood from the following description of speci?c
embodiments when read in connection with the
printing material by 108 0.10.
One possible method of making this revision is
by increasing the sensitivity of the transmission
integrator of the printer by 10g 0.10 for red trans
mission integrations. We have discovered how
accompanying drawing in which,
this can be done automatically and will now de
scribe our invention in connection with di?erent
Fig. 1 is a diagrammatic view, in perspective,
of the essential mechanism and circuit organiza
embodiments of the color printer shown in the
above-noted copending Tuttle and Brown ap
tion of one embodiment of a combined color
printer and compensating unit constructed in 15 plication.
We will ?rst consider the application of the
accordance with the present invention,
Fig. 1A is a wiring detail showing the hook-up
present invention to an embodiment of the color
printersuchasthatsh0wninl'1gs.iand6ofthe
between the integrating cell of the printer and
noted Tuttle and Brown applications. As shown
the compensating cell of the compensating unit
in Fig. i of the present application this embodi
in accordance with the arrangement of P18. 1,
ment of the printer comprises a standard projec
Fig. 2 is a plan view of a color negative used
tion printer having a “white" light source II. a
to make the compensator chart used in the com
carrier for negative ll, a projection lens II. and
pensating unit of Fig. 1,
Fig. 3 is a diagrammatic view, in perspective,
means, not shown. for holding a sheet of multi
layer color sensitive printing paper it in the focal
of the essential mechanism and circuit organiza
plane of the lens. A filter disk It is disposed
tion Of a combined color printer and compensat
between the negative and the lens and includes
ing unit constructed in accordance with another,
and preferred, embodiment of the present inven~
three ?lters. one each of red, green and blue,
designated R, G and B, respectively, which may
tion,
be individualLv indexed into the printing beam
Fig. 4 is a horizontal sectional view of a com
transmitted by the color negative in the carrier
pensating unit suitable for use in the arrangement
to spectrally select separate colors from the beam
shown in Fig. 3.
for printing purposes. When making a color
Fig. 5 is a vertical section of the compensat
print, the ?lter disk is ?rst indexed to place the
ing unit shown in Fig. 4 and showing the stage
red ?lter R in the printing beam and the color
for illuminating the yellow chart area by a blue
sensitive paper is exposed to red light for a given
light,
time. Then the ?lter is successively indexed to
Fig. 6 is a view of the type of compensator
position the green and blue ?lters, G and B. in
chart adapted for use in the compensating unit
the printing beam and the same paper area is
shown in Figs. 3-5, and
successively exposed to each of these colors for
Fig.7 is a wiring diagram for the three lamps
a given length of time. When paper has been
of the compensating unit.
exposed to each of the primary colors for the se
Like reference characters refer to correspond
ing parts throughout the drawings.
lected time. the exposure is completed and the
print is ready for processing.
As pointed out above, the adjustments of the
negative-integrator type color printer referred 45 The printing time for each of the primary colors
to are empirically determined and are correct only
is ?xed and the intensity of the light source is
for a given set of sensitivities of the individual
varied in accordance with the color balance of the
layers of the multi-layer color sensitive printing
negative so that the paper is given the same expo
material. If a change in any of these sensitiv
ities occurs as a result of change in paper or pro
cessing, the printer adjustments must be revised.
sure for each of the three colors.
60
To do this. a
light-sensitive cell it of the photo»emissive type
is disposed adjacent the lens in a position which
enables it to receive light passed by the negative.
This cell, known as the integrating and measuring
ing combination, relative to the old combination.
cell, is alternately covered by red. green and blue
or the one for which the printer is initially ad 55 ?lters in the same order as the printing beam.
These revisions can be computed if the semito
metric characteristics of the new paper-process
justed are known.
According to the present invention, one method
of making such determinations of sensitometric
characteristics consists of making sensitometer
exposures on the printing material with red,
green and blue light of such quality that each
exposes only a single emulsion layer of the multi
and for purposes of simplicity we have shown
the cell covered by the same ?lter as cuts the
printing beam for exposure purposes, although
thisisnotactuallvthecaseaswillbeappreciated
layer printing material. Bubsequent processing
by referring to the above-noted Tuttle and Brown
application. After a given color ?lter has been
indexed over the lens and cell. red for instance.
the cell integrates the red light transmitted by
then results in isolated areas of cyan, magenta,
and yellow dye deposits. The density level 0!
these dye deposits should be somewhere on the
The intensity of the printing source is then varied
by means of rheostat l'l until the cell gives a sig
straight-line portions of the printing material
nalthattheintensitwofthelightissu?icient
the negative and begins to measure its intensity.
for printing purposes. Then the exposure of the
dye deposits can be determined by a photo-elec
paper by that color, red by way of example, is
tric densitometer, using red, green and blue illu 70 started and maintained for a pre-selected time.
This procedure is then repeated with each of the
minants of such quality that the gamma of each
green and blue ?lters indexed into the printing
individual dye deposit of the paper as determined
beam and over the integrating cell.
by this densitometer is 1. Bay then that the com
The printer includes an automatic control of
parison of a new printing material with one cut
rently in use, and for which the printer is ad- I‘ thetypeshownin?ghandcompletelydescribed
characteristic curves. Now the density of these
2,500,040
5
,
-
6
in the above-noted copending application. Only
The compensating cell Ill is connected into
so much of this control will be brie?y described
herein as necessitates an'understandlng of the
the ampli?er circuit of the printer to act as a load
resistor of the ampli?er I03 which is handling
the response of the negative integrating cell Ii 0!
the printer. This hook-up is clearly shown in Fig.
1A. The sensitivity of the ampli?er is directly
proportional to the load resistance. The resist
ance of a photo cell is inversely proportional to
its illumination. Therefore, the sensitivity of the
10 ampli?er is now inversely proportional to the illu
mination of the compensating cell III, and the
present invention. The rheostat I1 is adapted
to be driven in both directions by a shaded-pole
reversible motor MP. The direction of drive of
this motor is controlled by a cam 6| which oper
ates the switch 60 to alternately connect diifer
ent ones of the shading windings CW and CCW
of the motor into circuit. At the end of an ex
posure with each color light the motor is con
log sensitivity of the ampli?er is directly propor
tional to the density of the paper dye deposits.
a minimum value after which the shading wind
The log intensity of the illuminant called for by
ings are reversed and the motor drives in a di 16 the printer ampli?er is, therefore, inversely pro
rection to cut the resistance out of the lamp
portional to the density of the dye deposit. Be
circuit. The integrator cell It integrates and
cause gamma is 1, the intensity of the printing
measures the intensity of the negative trans
light has been made inversely proportional to the
mitted light and when the intensity reaches a
sensitivity of the paper, and exact compensation
pre-selected value, as determined by the adjust
is therefore effected. As will be apparent from
nected to drive the rheostat II in such direction
as to cut the intensity of the printing source to
ment of the system, the output of the cell as am
pli?ed by ampli?er I03 trips a relay composed of '
coil 63 and switch 59 to break the motor circuit.
The exposure with the color light ‘as so adjusted
(red for instance) is then made with this adjusted
intensity and the procedure is repeated in suc
cession for both green and blue light.
Having brie?y ‘outlined the structure and op
eration of that part of the color printer which is
essential to an understanding of the present in
vention, we will now describe how the present
invention may be combined therewith to auto
an inspection of Fig. 1, when the integrating
photocell I6, is adjusting the red-printing inten
sity for the negative, the compensating unit ad
justs the ampli?er sensitivity according to the red
sensitivity of the paper, and likewise for the
printing with green and blue light. '
The compensator used in this‘ manner would
be moderately useful, but it can be made of much
more value if ‘the compensating chart I 29 is
printed on the printer it is to control. This not
only eliminates the need for the sensitometer, but
introduces complete compensation for any acci
matically compensate the printer control for
dental variation in the behavior of the automatic
changes in the sensitometric characteristics of a
new paper-processing combination relative to the
printer intensity controller.
combination for which the printer is initially ad
justed. According to the present invention we in
corporate the physical densitometer, described
above relative to determining the sensitometric
the instrument shops.
Suppose we have received a new printer from
It is to be adjusted to
make satisfactory prints on a paper of average
characteristics. Since it contains the compensat
ing unit above described, some set of re?ectors is
characteristics of a new paper and processing 40 required for placement in the compensating unit
to set the ampli?er sensitivities at an initial value.
combination, in the printer control. It is shown
in the box shown in dotted lines, labeled “com
A stable uniform gray re?ector can be used,
rather than a set of dye deposits. With this ‘gray
pensator unit” at the left end of Fig. 1. It com
prises a light source I25 of known intensity which
re?ector in place, the printer is adjusted by trial
can be successively intercepted by red, green and 45 until satisfactory prints result.
Now suppose we have available a transparent
blue ?lters Rc, Go and Be, respectively, carried
color chart or negative I32 such as is shown in
by disk I26 mounted on shaft I21. Also mounted
on shaft I2‘I'is a turn-table I28 on which is po
Fig. 2. The red, green and blue ?lters R, G, and
sitioned a compensating chart I29 having cyan,
B pass su?iciently narrow bands of the spectrum
magenta and yellow dye deposit areas, C. M, and 60 that when they are combined with any one of the
Y respectively, said chart being made by giving
projection lens ?lters the transmitted light ex
poses only one of the layers of the multi-layer
the paper to be used a sensitometric exposure to
printing paper. A cyan dye deposit will result
red, green and blue light and processing the same
from the image of the red ?lter, a magenta dye
by the processing procedure to be used in con
65 deposit from the green ?lter and a yellow dye
junction with prints made on the printer.
deposit from the blue. Transmittancesof the ?l
This chart is oriented with respect to the ?lter
ter sectors of this chart must be so adjusted that
disk I26 so that as the shaft I2‘! is indexed the
when it is used as a negative to make a print on '
cyan area will be illuminated by red light, the
the paper for which the printer has been ad
magenta area will be illuminated by green light
justed, this print can be used interchangeably
and the yellow area by blue light. ' Or, stating it
with the gray re?ector in the compensating unit.
another way, each of the primary color lights will
To make such adjustment easy, the color ?lter
illuminate an area the color of which is a sub
sectors should occupy a relatively small portion
tractive primary thereof. Or, each area of the
chart is illuminated by a light which is comple
of the chart area; the rest should be a uniform
mentary in color with respect thereto. The shaft 55 color and can conveniently be gray as indicated.
The adjustment is then made by adding neutral
22 on which the ?lter disk I5 of the printer is
mounted is positively connected to the shaft I21
density to the ?lter sectors.
'
so that corresponding color ?lters are moved into
A printed compensator chart can now be put
the printing beam and the light beam of the com
into the compensating unit and the printer is
pensator unit at the same time. We have indi
ready to make prints on the paper which pro
cated this connection as a chain drive I30 for
duced the compensator chart. This chart can
purposes of simplicity. Light re?ected by the re
stay in the printer as long as no change occurs
spective chart areas C, vM and Y are picked up by
in the color sensitvity of the printing paper used,
a photo-emissive type light-sensitive cell I3I
the processing balance, or printer behavior. The
which will be referred to as the compensating cell. 7‘ gray ?lter and the compensator chart negative
8,500,”
7
I" should remain available. If any change of
any of these factors occurs, the gray ?lter is
placed in the compensating unit and a new print
8
Reiernngnowtomgs.4,5,and6thecom
pensating unit of which the compemating cells
Ba,Bo.andBsformapartwilinowbedescribed.
or compensator chart is made with said negative
Three tungsten-?lament lamps L are mounted in
chart.
The resulting new compensator chart is
separate compartments of a housing I". These
then placed in the compensating unit, and the
color balance of the print automatically returns
to the point to which the original trial adjust
ment was made. Whatever changes the printer
lamps are preferably low-wattage lamps with
horizontal line ?laments. Each of the ?laments
is imaged by a high-aperture, condenser-lens pair
in on a slit Ill. The light forming the image
control, the paper or the processing tries to make 10 is ?ltered by an appropriate color filter I" placed
in the print balance will first take place on the
between the slit and the condenser lens pair.
print of the compensator chart, which will re
The?lterinfrontofoneofthelampsisred and
move the effect in the subsequent printing of the
is designated Fa, another is green and designated
picture negatives. The printing balance is,
Fe, and the last is blue and designated Pa. The
therefore, controlled solely by the characteristics
slits are on the axis of a semi-cylindrical end I"
of the compensator chart negative, and as long as
on the housing and around which is wrapped the
this is constant the printer will always return to
compensator chart III’, of the form shown in
making prints of the original color balance.
Fig. 6, and into which are cut windows III to
The present compensating unit is applicable
disclose the colored areas of the compensator
to the embodiment of the color printer shown in 20 chart. The slit is covered by a ?eld lens I“
the above-noted Tuttle and Brown copendlng
‘which images the condenser lens on the com
application which uses barrier-type photocells
pensator chart. The chart is held in wrapped
for integrating purposes, as well as the embodi
relation with the end of the housing by any suit
ment using photo-emissive type cells as set forth
able means such as a ?exible metal strap, not
above, and such a modi?cation of the present 25 shown, which is also wrapped around the end of
the housing in covering relation with the chart.
invention will now be described.
The arrangement and size of the colored areas
In Fig. 3 we have shown the embodiment of the
in the compensator chart conform to that of the
color printer control shown in Fig. 7 of the above
window dimensions and pattern in the semi-cylin
noted Tuttle and Brown application modi?ed to
drical end of the housing and is optional. This
incorporate the cells of a compensating unit in
chart is made exactly in the same manner as
accordance with the present invention. A com
the one described in connection with the ?rst
plete description of this type of printer control
can be had by referring to said Tuttle and Brown
mentioned embodiment of the invention, and the
application, but enough of it will be brie?y out
negative of which this is a print comprises three
lined here to make the application of our com
color ?lters on a gray background, in an ar
pensating unit thereto readily understandable.
rangement which is, naturally, a proportional
reduction of the print arrangement, the reduction
being equal to the magni?cation factor of the
printer. The color ?lters used in this negative
This form of the printer control uses three sep
arate integrating cells of the barrier-layer type,
one Ca covered with a red ?lter, another Co cov
ered with a green ?lter, and the third Ca cov
ered with a blue ?lter. These cells measure the
light transmitted by the color negative i4 and
are individually cut into the measuring circuit
by means of a cam 42 operating switches Sn, So
and Se in the proper timed relation with the
indexing of the ?lter sectors R, G and B into
the printing beam. In this embodiment, a servo
system is used to control the intensity of the
printing source it. This involves connecting a
standard source of potential in bucking relation
to the output of the integrating cell to provide
a null system, and feeding the output of the cell
and standard potential through a servo-amplifier
32, the reversible motor Me of which drives the
rheostat II to adjust the intensity of the printing
are the same as the printer lens ?lters, plus neu
tral densities in the required amounts.
Each area of the compensator chart, then. is
illuminated by a slit source which emits light of
selected quality only in directions which con?ne
the illumination to the desired chart area. and
all of the light is directed to the chart areas in
a radial plane. Since the surface of the com
pensator chart is specular. all of the light re
?ected by the surface returns to the cylindrical
axis and is largely lost. The light which is to
activate the compensating cells is that which is
diffusely re?ected by’ the print areas. Part of
this light from each chart area falls on two of
the barrier layer type compensating cells having
the same color sensitivity so disposed as to safely
lamp l0 until the output of the measuring cell is
avoid the specular reflections, but to intercept as
equal and opposite to that of the standard source
much as possible of the diffused light. see Fig. 5.
of vpotential connected in bucking relation thereto.
The only change in this printer control which
the present invention necessitates is the substitu
Because of space limitations, the compensating
cells Ba and Bo which are to be illuminated by
light re?ected from the cyan and magenta areas
of the chart are each so placed, not shown, as
to receive light from both print areas. Confmion
of response is eliminated, however, by covering
tion of three barrier-layer type photo-cells Ba,
Ba and Ba for the standard source of potential
normally used to buck, or oppose, the output of
measuring cells Ca, CG and Ci; of the printer.
These photo cells Ba, Ba and Ba constitute a part
of the compensating unit to be described and the
compensating cell Ba is connected in opposition
with the red integrating cell Ca and the com
pensating cell B0 in opposition to the integrating
cell Co and the compensating cell Ba in opposition
to the integrating cell Ca. Each of the inte
grating cells Ca, Co, and Cs and its corresponding
one of compensating cells Ba, Bo and Ba are con
nected in pairs and in bucking relation into the
control circuit by rotation of the cam 42.
TI
half of each cell with an opaque sheet. so that
light re?ected from the cyan print area acts
onlyontheuncoveredhalfofonecelLandthe
light from the magenta area acts only on the
uncovered half of the other cell. The responses
of these small cell-elements are adequate. The
amount of energy re?ected by the yellow print
area is so small. however, that two complete cells
andalargerchartareaaremedtoimprovethe
emciency of its interception.
As will be appreciated, the compensating cell
Baofthecompensatingunitwhichmeasuresthe
2,000,040
I
light di?usely re?ected from the cyan area of the
chart when illuminated by red light is connected
in opposition to the integrating cell Ca of the
printer which measures the intensity of the red
10
means for individually integrating and measuring
the intensity of each of the three colors in the
printing beam transmitted by the negative and
adapted to give a signal when the intensity of
each colored light is a pre-selected value; means
for varying the intensity of each of the three
light transmitted by the negative. Likewise the
compensating cell Ba measuring the light re
ilected by the magenta area when illuminated by
green light is connected in opposition to the green
filtered integrating cell Co, of the printer. And
?nally, the compensating cell Be is connected in
opposite with the blue-sensitive integrating
pensator unit connected to the photo-electric in
tegrating and measuring means to modify the
cell Ci; of the printer.
sensitivity oi’ response thereof and' adapted to
Where more than one
colors in the printing beam and adapted to be
controlled by the signal given by said photo-elec
tric integrating and measuring means; of a com
compensate for variations in the exposure re
quirements of a negative introduced by changes
re?ected from a single chart area they will be
connected in parallel so that their output adds up 15 in the color sensitivity of the printing material
as compared with the color sensitivity for which
and is the equivalent to the output of a single cell
the printing control is initially adjusted and
having twice the sensitivity of one.
changes in response of said photo-electric in
A compensating unit of this type provides cor
tegrating and measuring means of the printer.
rect action for a color printer using barrier layer
2. In a color printer for making color prints on
type integrating cells, provided a null-balancing 20
a color-sensitive printing material from a color
system is used. That is, the response of the com
negative, the combination with means for uni
pensating cells and the response of the integrat
formly illuminating said negative with a light
ing cells must be equal and of opposite polarity
source including the three primary colors; means
when the printer is at printing ‘balance. In this
application, instead of requiring that increased 25 for projecting an image of said negative onto a
sheet of color-sensitive material; means for in
compensator response decrease the integrator
dividually integrating and measuring the intens
sensitivity, an increase in compensator response
ity of each of the primary colors in the printing
directly requires an equal increase 01' integrator
beam transmitted by said negative and adapted to
response to return the printer control to balance.
With the present compensator unit it is possible 30 give a signal when the intensity of each color
reaches a pre-selected value; means for varying
to readily adjust the printer action to accommo
the intensity or each of the primary colors in the
date abnormal color negatives merely by vary
printing beam and adapted to be controlled by
ing the intensity of the compensator light sources.
the signal given by said integrating and measur
For example, in Fig. 7 we‘have shown how the
lights of the compensating unit may be wired so 85 ing means; of means for compensating for varia
tions in the exposure requirements introduced by
that each lamp L of the compensator unit can be
changes in response of said means for integrating
operated at any one of three intensity levels, the
and measuring the intensity of the primary colors
changes occurring simultaneously if a simple
'in said printing beam, due to a change in the
change to in over-all print density is required, or
independently, if changes in color balance are re 40 color sensitivity of the printing material and
processing procedure for the exposed printing
quired. The three lamps are connected in par
material, and comprising a compensating chart
allel to the secondary of a transformer T con
which is a positive print made by said printer on
nected to a 110 0 line. By turning a dial “2
a sample of the color printing material to be'used
over a scale marked “over," "normal" and “un
der" a di?erent amount of resistance can be cut 46 and exposed to light of the three primary colors,
each having a given intensity and processed ac
into the primary of the transformer T to simulta
cording to the procedure to be used; means for
neously change the intensity of each of the three
illuminating this chart with a red, a green and
compensating lamps for control of the over-all
a blue light source of given intensity; means for
density of the prints. On the other hand, each
of the lamps have a group of different resistances 50 measuring the amount of light re?ected by said
chart when illuminated by each of said primary
in their own individual circuits which may be in
color light sources; and means for connecting
dividually cut into the circuits of the lamps by
said integrating and measuring means with said
turning the proper one of the dials Ill between
last-mentioned measuring means whereby the re
positions marked “over,” “normal” and "under”
on the panel of the control to alter the color bal 55 sponse, and ultimately the signal, of the former
is modified by and in accordance with the re
ance of the prints made from abnormal negatives.
sponse of the latter.
Each lamp circuit will preferably include an ad
3. In a color printer for making a color print
justable .resistance R for facilitating initial ad
on a color-sensitive printing material from a color
justment of the compensating unit.
While we have shown and described certain 60 negative, the combination with means for uni
compensating cell is used to measure the light
speci?c embodiments of our invention we are
aware that many modi?cations thereof are pos
formly illuminating said negative with the light
source including red, green and blue light; photo
electric means for individually integrating and
sible. Our invention, therefore, is not to be lim
measuring the intensity of each of the three col
ited to the precise details of construction shown
and described but is intended to cover all modi 65 ors in the printing beam transmitted by said neg
ative and adapted to give a signal when the in
?cations coming within the scope of the appended
tensity of each color is a pre-selected value;
claims.
means for varying the intensity of each of the
Having thus described our invention, what we
three colors in the printing beam and adapted to
claim is new and desire to protect by Letters Pat
70 be controlled by the signal given by said photo
ent of the United States is:
,
electric integrating and measuring means; of a
1. In a color printer for making a color print
compensator unit for compensating for variations
on a colors-sensitive printing material from a
in the exposure requirements introduced by
color negative, the combination with means for
changes in the color sensitivity of the printing
illuminating ‘said negative with a light source in
cluding red, green and blue light; photo-electric 76 material and by changes in the response of said
2,500,040
-
12
ll
photo-electric integrating and measuring means;
for variations in the exposure requirements or a
negative introduced by changes in the color semi
tivity of the printing material as compared with
that for which the integrating and measuring
means of the printer is initially adjusted; and
comprising a compensating chart having separate
cyan, magenta and yellow areas and produced by
making a color print on the printing material
to be used on the printer using given red, green
and blue ?lters, respectively, as a negative and
using known exposure conditions; means for il
luminating each of said cyan, magenta and yel
and comprising a color-compensating chart made
on the above printer by exposing a sheet of the
printing material to a negative including sepa
rate red, green and blue ?lter areas of known
transmission characteristics, whereby said chart
includes three separate cyan, magenta and yel
low dye areas; means for illuminating each of
said chart areas with a light source of known
intensity and of a color substantially comple
mentary to that of the area; a photo-cell for
measuring the amount of light reflected from
each of said chart areas, and means for connect
low areas of said chart with a beam of known in
ing said photo-cell into the circuit of said photo
tensity and of a color substantially complemen
tary thereto; a compensating light-sensitive cell
for measuring the amount oi’ light reflected by
each of said chart areas when so illuminated:
electric integrating and measuring means of the
printer so that the sensitivity of response of the
latter is modi?ed in accordance with and by the
output of the former.
and means for connecting said compensating
4. In a color printer for making a color print
light~sensitive cell in circuit with said photo
on a color-sensitive printing material from a 20 electric cell so that the output of the latter is
color negative, the combination with means for
modi?ed in accordance with the output of the
uniformly illuminating said negative with a light
source including red, green and blue light; photo
electric means for individually integrating and
measuring the intensity of each of the three colors
of the printing beam transmitted by said negative
and adapted to give a signal when the intensity
former.
6. A color printer according to claim 5 in which
a single photo-electric cell of the photo-emissive
type is disposed in the printing beam to integrate
and measure the intensity thereof, and an am
pli?er is connected in circuit therewith to ampli
of each color is a pre-selected value; means for
varying the intensity of each of the three colors
in the printing beam and adapted to be controlled ;
by the signal given by said photorelectric inte
grating and measuring means; of a compensator
unit for compensating for variations in the ex
iy the output thereof; means for successively in
dexing red, green and blue ?lters into the print
ing beam in front of said cell to spectrally select
the light striking said cell; and said compensator
includes a "white" illuminating beam; means for
successively moving the di?erent color areas of
posure requirements introduced by changes in
said chart into said illuminating beam; means for
the color sensitivity of the printing material, and I ~ successively moving red, green and blue ?lters
comprising a compensator chart bearing three
into said illuminating beam in front of said chart.
color areas each being a different one of the
subtractive primary colors; means for illuminat
said two last-mentioned means synchronised so
that each color area of the chart is illuminated
ing each of said areas of said chart with a source
by a color substantially complementary thereto;
of known intensity which is complementary in 1 - means for synchronizing said two sets of color
color to the area; means for individually inte~
filters so that at any time a ?lter of the same color
grating and measuring the intensity of light dif
isinterposedintheprintingbeamandsaidil
fusely reflected by each of said areas; and means
luminating beam; and means for connecting said
compensating cell into the ampli?er circuit so
for connecting the means for integrating and
measuring the intensity of the primary colors in
the printing beam and the means for integrating
and measuring the intensity of the light diffusely
re?ected by each of said color areas together so
that the response of said ?rst integrating and
measuring means and measuring light of one of
the primary colors is modi?ed in accordance with
the response of the second-mentioned integrat
ing and measuring means when measuring the
that it acts as a load resistor for said ampli?er.
7. Acolorprinteraccordingtoclaimbandin
eluding means for varying the intensity of the
illuminating means for said chart areas to ad
Just the over-all density and to alter the color
50 balance oi a print made on the printer.
.
8. The color printer according to claim 5 and
in which separate sources are provided for il
luminating each of said chart areas; and includ
amount of light re?ected by a color area the color
ing means for simultaneously adjusting the in
of which is complementary to that of said pri 55 tensity of each of said sources by the same
mary color.
>
.
amount to obtain a change in over-all density
5. In a color printer for making a color print
of a print made on the printer.‘
on a color-sensitive printing material from a color
9. A color printer according to claim 5 and in
negative, the combination with means for illumi-.
which separate sources are provided for illum
nating said negative with a light source including 00 inating each of said chart areas; and including
red, green and blue light; means for individually
means for individually adjusting the intensity
varying the intensity of each of the red, green
of each of said sources to obtain a change in
and blue lights in the printing beam transmitted
color balance in a print made on the printer.
by the negative; means including a photo-electric
10. A color printer according to claim 5 in
cell disposed in the printing beam for individu
which three photo-voltaic type photo-cells, one
ally integrating and measuring the intensity of
sensitive to red light, one sensitive to green light.
each color light in the printing beam and adapted
and a third sensitive to blue light, are disposed
to give a signal for stopping said intensity vary
in the printing beam to integrate and measure
ing means when the intensity of each color light
the intensity thereof; means for selectively con
in the printing beam reaches a pre~selected value, 70 necting each of said cells in circuit with said
the response of said integrating and measuring
integrating and intensity measuring means; and
means being initially adjusted in accordance with
said compensator includes means for illuminat
a printing material having a given color sensitiv
ity: of a compensating unit connected to said in
ing each of said color areas of the chart with a
tegrating and measuring means to compemate
tially complementary thereto; a photo-voitaic
light of known intensity and of a color substan
8,500,049
13
i
compensating cell disposed to scan the cyan area
of the chart, a second photo-voltaic type com
pensating cell disposed to scan the magenta
.
.
14
.
13, in which the illuminating means for each
chart area includes ‘an illuminated slit substan
tially coinciding with the axis of said semi-cyr
area of the chart, and a third sensitive photo
voltaic compensating cell disposed to scan the
yellow area of said chart; the compensating cell
lindrical end of the housing, and wherein each '
integrating cell and the compensating cell scan
ning the yellow area connected in opposition with
each chart area for controlling the over-all den
photo-electric cell is disposed adjacent to said
slit and outside of the cone of light passing be
scanning the cyan area connected in opposition,
tween said slit and the chart area.
with the red sensitive integrating cell,'the com
15. A compensating unit according to claim
pensating cell scanning the magenta area con
13, including means for simultaneously adjust
nected in opposition with the green sensitive 10 ing the intensity of the illuminating means for
sity of the color print and for individually adjust
the blue-sensitive cell so that each pair of cells
ing the intensity of the illuminating means for
is adapted to be selectively connected in circuit
the different chart areas for controlling the color
with said integrating and intensity measuring 16 balance of the print.
means of the printer.
->
.
16. A compensating unit according to ‘claim
13, in which the illuminating means for each
of‘ the respective chart areas comprises a sep
the negative-integrator type and for indicating
arate lamp; a circuit for connecting each of said
any adjustment required‘ in the response of the
three lamps to a common source of potential;
photoelectric integrating and measuring means 20 9. variable resistance in series with each separate
11. A compensating unit of the type described
for use in combination with a color printer of
' thereof which might be required because oi’ a
change in the color sensitivity of a given print
ing material to be used, comprising a color com
pensating chart having threeseparate areas each
of a different‘ color which is a positive print made
with said printer on a sample of the color print
ing material to be used in the printer and expomd
to light of the three primary colors of given in
lamp for varying the intensity of the lamps indi
vidually for control of color balance in a color
print; and a variable resistance in the circuit
25 common to all of the lamps for control or over
all density of a color print.
17. A compensating unit of the type described
for use in combination with a'color printer oi’
the negative-integrator type and for indicating
tensity and processed according to the proce
30 any adjustmentrequired in the response of the
dure to be used; means for illuminating each of
photoelectric integrating and measuring means
said chart areas with a light beam of known
thereof which might be required because of a
intensity and of a color substantially comple
change in the color sensitivity of a given printing
mentary to that of the area, and a separate
material to be used, comprising a color com
light~sensitive cell for scanning each of said 35 pensating chart having three separate areas of
illuminated chart areas to measure the amount
a different color which is a positiveprint made
of light re?ected thereby, the output of each
with said printer on a sample of the color print
oi’ said light-sensitive cells indicating any change
ing material to be used in the printer and exposed
in response which might be required in the
to light of the three primary colors of given in
printer control to compensate for changes in the ii tensity and processed according to the procedure
actual or apparent color sensitivity of the print
ing material to be used in the printer.
12. A compensating unit according to claim
11, and in which said light-sensitive cells are
so disposed relative to the chart areas they re
spectively scan and the chart areas are so illum
inated that only the light di?‘usely re?ected by
said areas reaches said cells and is measured
thereby.
to be used; means for projecting a beam of
“white” light of known intensity onto said chart;
means for successively indexing the different
areas of said chart into said beam; a tri-color
45 ?lter including separate ?lters each of a color
substantially complementary to one of the three
areas; means for successively indexing said ?lters
to bring di?erent ?lters into said illuminating
beam, said last-mentioned means synchronized
13. A compensating unit of the type described
with said chart indexing means so that each
comprising a housing having a semi-circular end 50 chart area is illuminated by light complementary
wall provided with three spaced windows; a com
to itself in color; and a light-sensitive cell for
pensating chart having three separate areas,
measuring the amount of light reflected by each
each of a different color, wrapped around the
oi’ said chart areas when so illuminated.
semi-circular end of said housing with a differ
ent one oi’ each of said colored areas framed by 55
FRANKLIN C. WILLIAMS.
each of said windows and facing the axis of said
FORDYCE M. BROWN.
semi-circular end; separate means in said hous
ing for uniformly illuminating each of the chart
areas with light rays directed radially to the
chart area and of known intensity and being a
color substantially complementary to that of the
chart area illuminated thereby; and a plurality
of photo-electric cells in said housing, each ar
ranged to scan a different chart area, said cells
disposed relative to the chart areas and the light
rays illuminating the same so that they are not
a?ected by light specularly re?ected by said
areas but only by light di?'usely re?ected by
said chart areas.
,
nmnncas orran
The following references are of record in the
?le of this patent:
.
.
UNITED STATES PATENTS
Number
2,169,009
2,244,992
2,289,161
2,319,898
2,384,280
2,388,842
14.A compensating unitaccordingtoclaim 10 2,402,880
Name
I
Date
Seymour ......... _. Aug. 8,
Guerrero ________ -_ June 10,
Morse ..__-_-'_ _____ -_- Jan. 8,
Zurian __-_‘ ______ __ May 25,
Goldsmith ______ _- Sept. 4,
Hanson .........-- Nov. 13,
O'Grady __. ____ _- June as,
1939
1941
1942
1943'
1948
1949
me
Certi?cate of Correction
Patent No. 2,500,049
March 7, 1950
FRANKLIN O. WILLIAMS ET AL.
It is hereby certi?ed that errors appear in the printed speci?cation of the above
numbered patent requiring correction as follows:
Column 9, line 11, for the word “opposite” read opposition; column 14, line 46,
after “three” insert chart;
and‘ that the said Letters Patent should be read with these corrections therein that
the same may conform to the record of the case in the Patent O?ice.
Signed and sealed this 27th day of June, A. D. 1950.
[am]
THOMAS F. MURPHY,
Assistant C'ommz'ssz'oner of Patents.
Certi?cate of Correction
Patent No. 2,500,049
March 7, 1950
FRANKLIN C. WILLIAMS ET AL7
It is hereby certi?ed that errors ‘appear in the printed speci?cation of the above‘ ’
numbered patent requiring correction as follows:
Column 9, line 11, for the word “opposite” read opposition; column 14, line 46,
after "three.” insert chart;
and that the said Letters Patent should be read with these corrections therein that
the same may conform to the record of the case in the Patent O?ice.
Signed and sealed this 27th day of June, A. D. 1950.
[BM]
THOMAS F. MURPHY,
Assistant Oommz'ssz'aner of Patents.
Certi?cate of Correction
Patent No. 2,500,049
March 7, 1950
FRANKLIN O. WILLIAMS ET ALf
It is hereby certi?ed that errors appear in the printed speci?cation of the above
numbered patent requiring correction as follows:
Column 9, line 11, for the word “opposite” read opposition; column 14, line 46,
after “three” insert chart;
and that the said Letters Patent should be read with these corrections therein that
the same may conform to the record of the case in the Patent Of?ce.
Signed and sealed this 27th day of June, A. D. 1950.
[am]
THOMAS F. MURPHY,
Assistant Commissioner of Patents.
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