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Description  |
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BACKGROUND OF THE INVENTION
This invention relates to a method for printing a photographic picture, by
which a selected image frame on an original picture film can always be
printed with a same condition.
When an image frame on an original film such as a negative film is printed
by a conventional photographic printing apparatus, the image frame is
subjected to photometry each time by means of LATD (Large Area
Transmittance Density) or an image sensor such as disclosed for example in
Japanese Patent Laid-open No. 60-177337. The above image sensor method is
referred to "scanner photometry" hereinafter. It has been common that a
printing exposure amount or an exposure correction value obtained thus by
such scanner photometry is not memorized by the apparatus.
Hence, even when a selected same image frame is printed by a photographic
printing apparatus having a photographic system for the scanner photometry
once again or repeatedly for multiple printing, test printing, re-making
and re-printing of the selected image frame, the same image frame has to
be subjected to photometry at each time when such printing occurs. That
is, an exposure calculation operation is made on the basis of the
photometric data each time when even the printing is made. There is a
drawback in this way of the photometric printing that even when the same
image frame is repeatedly or one again printed, the exposure amount
differs each time whereby densities of the prints vary each time. This
variation or deviation of exposure correction amount is due to that when a
negative film is removed once from a position where its image density was
measured, it can hardly be relocated exactly to the same position, that in
the case of image characteristic values such as the maximum densities or
the minimum densities being employed as reference data, then reading
undergoes variations or deviations on account of even slight fluctuations
of the negative film or a small electrical noise thereabout, and that a
different exposure operation formula could consequently be employed on
account of even a small variation or deviation of the image characteristic
values whereby there is produced a dispersion of the exposure correction
amount.
Especially when a test print is made for a large sized picture, employing a
photographic printer provided with a system having the scanner photometry,
and if the test print is not identical with lately corrected multiple
prints, there should be produced serious problems including a waste of
labor and printing papers, an operational confusion and resulting
unreliability on the photographic printer. It could be said that these
problems are inherent to conventional photographic printing method. There
has been developed a countermeasure which is to cope with such problems
and in which an exposure correction amount is outputted on a photographic
printing paper, and a next printing is made by inputting the outputted
value while an input is manually made so that the exposure correction
amount is interrupted. This countermeasure accompanies however a drawback
that one is apt to forget to have the exposure correction amount
interrupted or reoperated, anddoes not constitute therefore an entirely
reliable solution.
SUMMARY OF THE INVENTION
In view of the above-described contemporary backgrounds, it is a principal
object of this invention to provide a photographic printing method by
which prints of an identical density can be obtained always without any
dispersion even when a selected same image frame is printed more than one
time after test printing and so on.
According to one aspect of this invention, for achieving the objects
described above, there is provided a photographic printing method which
comprises the steps of: subjecting image frames on an original film to be
printed to a photometry for obtaining an exposure amount for each image
frame and thereby consequently obtaining image characteristic value and an
exposure correction amount for each image frame as data memorized; and
printing the subjected image frame either by utilizing the memorized data
when said subjected image frame is identical with one of the image frames,
data of which have been memorized, or by utilizing the data which have
been obtained by the photometry but have not been memorized when said
subjected image frame is not identical with any one of the image frames,
data of which have been memorized.
According to another aspect of this invention, there is provided a
photographic printing method which comprises the steps of: subjecting
image frames on an original film to be printed to a photometry for
obtaining an exposure amount for each image frame and thereby consequently
obtaining an image number and an exposure correction amount for each image
frame as data memorized; and printing the subjected image frame either by
utilizing the memorized data when said subjected image frame is identical
with one of the image frames, data of which have been memorized, or by
utilizing the data which have been obtained by the photometry but have not
been memorized when said subjected frame is not identical with any one of
the image frames, data of which have been memorized.
The nature, principle and utility of the invention will become more
apparent from the following detailed description when read in conjunction
with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings:
FIG. 1 is a block diagrammatic view showing an example of a photographic
printing apparatus which is employable for the practice of this invention
method;
FIG. 2 is a block diagram similar to FIG. 1, in which a part of the
photographic printer is shown in more detail;
FIG. 3 is a flow chart showing an example of this invention method;
FIGS. 4A and 4B are plan views for the explanation of image frames of the
negative film, respectively;
FIG. 5 is a view showing an example of arrays of data to be memorized; and
FIG. 6 is an explanatory perspective view showing the reading of bar codes
of the negative film.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In FIG. 1 which shows an example of a photographic printing apparatus of a
color compensation filter and cut-off filter system, to which the present
invention method is applicable, a negative film (an object) 1 is
illuminated by a light source 4 through color compensation filters 2 of
yellow Y, magenta M and cyan C and through a mirror box 3. The light
penetrated through the negative film 1 is exposed on a photographic paper
(or color paper) 8 via cut-off filters 5 of YC, MC and CC, a lens system 6
and a black shutter 7. The photographic paper 8 wound on a supply reel 81
is intermittenly wound up onto a take-up reel 82 after it has been exposed
at a printing section along an optical axis LA and after it has been
developed at a processing section 10. A mirror 30 is removally provided
between the cut-off filters 5 and the lens system 6 in a path of the
optical axis LA, so that another optical axis LB converted at about a
right angle to the optical axis LA is produced. There is provided a zoom
lens 23 next to the mounted mirror 30 in the emitting direction of the
another optical axis LB, while in the advanced path of the optical axis
LB, there is also provided an image sensor 20 which works as an image
pick-up means. Image signals PS transmitted from the image sensor 20 are
inputted into a control circuit 100. In the path of the additional optical
axis LB between the zoom lens 23 and the image sensor 20, there is
removally mounted another mirror 31 which produces a further another
optical axis LC converted from the optical axis LB at about a right angle
thereto. In advance of the mirror 31 thus mounted in the path of the
optical axis LC, there is provided a photometric device 24 such as an
image sensor, photodiodes and the like for detecting image densities of
three primary colors of blue B, green G and red R. The image signals
detected by the photometric device 24 are converted to density signals DS
by a logarithmic conversion circuit 25 and inputted to the control circuit
100, whereby printing exposure conditions are determined by a
predetermined exposure operational formula and whereby the color
compensation filters 2, the cut-off filters 5 and the black shutter 7 are
controlled respectively through a color compensation filter driving
circuit 27, a cut-off filter driving circuit 26 and a shutter driving
circuit 28 so that an image from the negative film 1 conveyed to the
printing section is printed onto the photographic paper 8 and subjected at
the processing section 10 to the devlopment, bleaching, fixing, washing
and drying.
The mirror 30 is manually or automatically removed outside of the optical
axis LA when the negative film 1 is being printed, while it is manually or
automatically set in the path of the optical axis LA as illustrated in
FIG. 1 when a CRT 22 is being operated by the image sensor 20 and when the
photometric device 24 is also being operated. The mirror 31 is mounted in
the optical path LB as illustrated in FIG. 1 when the negative film 1 is
being subjected to the measurement by the photometric device 24, while it
is manually or automatically removed from the path of the optical axis LB
when a display is being given to the CRT 22. The zoom lens 23 works to
obtain always an image of a constant size even if the negative film 1
differs in its size. Dimensional information on the negative film 1 is
manually or automatically inputted into the control circuit 100 so that
the zoom lens 23 can be actuated thereby.
The image on the negative film 1 caught by the image sensor 20 through the
mirror 30 and the zoom lens 23 is transmitted to the CRT 22 through the
control circuit 100 and displayed on the CRT 22 by such luminance and
color conditions which are correspondent to an exposure amount obtained by
a basic exposure formula. The control circuit 100 can also receive a
manually inputted correction value CR through the operation of a manual
input adjustment apparatus 21 such as a keyboard.
Detailed structures of the control circuit 100 is shown in FIG. 2, in which
the image signals PS from the image sensor 20 are memorized in a frame
memory 102 after they have been converted to digital values by an A/D
(analog-to-digital) converter 101. When the image signals PS of one frame
is memorized in the frame memory 102, the data are read out and inputted
into a look-up table 103 where they undergo, in accordance with
predetermined tables, negative-positive conversion, gradation conversion,
color correction and so on. Then, data outputted from the look-up table
103 are converted by a D/A (digital-to-analog) converter 104 to image
indication signals of analog format, and are transmitted to the CRT 22. On
the other hand, photometric data from the photometric device 24 are
inputted into an image data analyzer 120 as the density signals DS through
the logarithmic conversion circuit 25. The data analyzed in the image data
analyzer 120 are inputted into a CPU 110. The CPU 110 is operatively
connected with a memory 111 so that it controls the operational sequence
of the frame memory 102 and the look-up table 103, and so that it
controls, as operated, the luminance and tone of the images displayed on
the CRT 22. In accordance with the dimensional information on the negative
film 1, the zoom lens 23 is actuated to a predetermined magnification, by
a zoom lens driver 130, through the CPU 110.
With the photographic printing apparatus as described above, the printing
method in accordance with this invention is carried in accordance with a
flow chart as shown in FIG. 3 for example.
The negative film 1 (or original film) as shown in FIG. 4A is mounted at a
predetermined position of the photographic printer (Step S1), and the
first image frame 1A of the negative film 1 is positioned at the printing
section (Step S2). Then, the positioned frame is subjected to the scanner
photometry by the image sensor 20 and the photometric device 24 (Step S3).
An average density of the image frame is obtained by means of the
photometric data given by the photometric device 24 (Step S4), and an
exposure amount is determined by the CPU 110 (Step S5). By the employment
of the above photometric data and in accordance with such method as
described in Japanese Patent Laid-open No. 60-177337 for example, the
image characteristic values and the exposure correction amount are
obtained by calculation, and the calculated data are memorized in the
memory 111 (Steps S6 to S9). Therefore, in a memory area 111A of the
memory 11, there is memorized an image characteristic value and an
exposure correction amount for the image frame 1A as shown in FIG. 5. That
is, image data comprising of the image characteristic value and the
exposure correction amount for each image frame are stored in each
corresponding memory area in the memory 111 one by one in the succeeding
order of frames.
Thereafter, it is automatically determined whether or not an image
characteristic value which is identical to that of the selected image
frame 1A has been memorized in the memory 111 with respect to the
identical image frame which has been printed (Step S11). When it is
determined that the selected image frame 1A is identical to the one which
has been memorized in the memory 111, the image frame 1A is printed by
means of the exposure amount obtained by the photometry at the above step
S5 and the exposure correction amount which has been memorized in the
memory 111 (Step S12). In this instance, the image characteristic value
and the exposure correction amount for the present image frame obtained in
the above steps S6 to S9 are not utilized and they are eliminated from the
memory 111 (Step S13). This elimination of the image data shall not
adversely affect the future printing, since the image data which has been
previously memorized with respect to the identical image frame remain in
the memory 111. When the same frame is found in the above step 11 that the
present image frame is not identical to any frame, data of which has
already been memorized, the image frame is printed by means of the
exposure correction amount which has been measured photometrically,
memorized and subjected to operation with respect to the present image
frame at the steps S3 to S9 (Step S14).
In the determination whether an image frame is identical to a previously
memorized image frame or not, the former shall be determined as identical
with the latter if the deviation of their image characteristic values is
within .+-.5%. If the deviation is beyond the above tolerance, they are
determined as not identical to each other. The comparison of image frames
by way of their image characteristic values is disclosed for example in
Japanese Patent Laid-open No. 54-26729 and No. 59-83280. In place of the
image characteristic values, data on picture elements can be utilized for
the determination of identity between two image frames. That is, the data
on the picture elements of two image frames are compared to each other for
obtaining an average deviation therebetween and for determining thereby
their identity. In this method, it is not practical to have all picture
element data memorized, while it is prerequisite that the number of data
on the picture elements can represent well the characteristics of the
image frames, nevertheless the number should be reduced as small as
possible. It shall be noted that data on the picture elements are also
included to those image characteristic values which are employable in this
invention method.
The reference for judgement if an image frame is identical with the one
which has been already memorized, is made succeedingly one by one only
with respect to a specific area of the memorized data in the memory 111 to
which the image frame belongs. When it is found that no identical data
exists in the specific areas, it is decided that the image frame is not
identical with any data in the memory 111. However, when it is apparent
that an image frame is going to be subjected to the photometry not for the
first time (in the case of, for example, making a corrected print after a
test printing), memory data which has the greatest resemblance to the
image frame could be used even if the data identical to the image frame
have not been found.
After an image frame data of which has not previously been memorized is
printed by using its own fresh data, it is checked if all required frames
of the negative film 1 have been printed or not. If they have not been
printed, a remnant image frame such as the frame 1B is conveyed and
positioned at the printing section, and the photometry and the printing as
described above are repeated until all image frames of the negative film 1
are printed.
While in the embodiment described above, the judgement of identity of an
image frame with memorized data is made by the comparison of the image
characteristic values or the image data, the judgement could be made also
by the comparison of frame numbers affixed to respective image frames 1A,
1B, . . . of the negative film 1 or printing numbers which have been used
in printing operation, with those frame numbers or printing numbers of the
negative films which have been previously printed and memorized in the
memory through their input thereto through the manual input adjustment
apparatus 21.
Image frame numbers could automatically be read out by means of bar codes
affixed to side edges of a negative film. An example of such bar codes is
shown in FIG. 4B, in which a photographic film 200 is 135mm in type,
having a series of full-sized image frames 201 (201A, 201B, . . . ) with
predetermined distances therebetween. Adjacently to both sides of the
photographic film 200, there are provided a number of perforations 202 and
203 with constant distances therebetween, which perforations operatively
engage with sprockets (not shown) for transferring the photographic film
200. On the photographic film 200 between its one of edges and the
perforations 203, there are formed, at the time of manufacture of the
film, a number of identically shaped bar codes 210 with specific distances
therebetween. These bar codes 210 indicate a name of manufacturer,
manufacturing lot numbers and others of the photographic film 200. On the
photographic film 200 between the edges in which the bar codes 210 are
formed and the perforation 203 between its another edge and the
perforations 202, there are formed, at the manufacture of the film, a
series of main frame numbers 211 and 212 with constant distances
therebetween, along its longitudinal direction, and in correspondence to
respective image frames 201. The main frame numbers 211 and 212 are formed
on both longitudinal sides of the photographic film 200 with pitches same
to those with which the image frames 201 are formed, and indicated one by
one by positive numbers beginning with "1" at a starting end of the
photographic film 200. Auxiliary frame numbers 213 are formed between the
mainframe numbers 211 and between the bar codes 210 on one of sides of the
photographic film 200 with lags of a half of the aforementioned pitch
apart from respective main frame numbers 211. The auxiliary frame numbers
213 are recorded by the number of a preceding main frame affixed with a
letter "A". There are also formed, at the time of manufacture of the film,
bar codes 214 and 215 between the main frame numbers 212. They are located
on one side of the photographic film 200 so as to be apart from the main
frame numbers 212 with constant distances in the right-handed direction in
figure. When those bar codes 214 and 215 are read out by a bar code reader
220 and the read data is transmitted to a data processing circuit 221 as
shown in FIG. 6, the main frame numbers 212 and the auxiliary frame
numbers 213 are detectable respectively. The bar code reader shall
preferably be combined with an automatic film transferring mechanism which
automatically conveys the photographic film 200 and an image-edge
detecting mechanism which detects a stop position of the photographic film
200 and makes it stop, so that by inputting an image frame member or a
printing number to the mechanisms through the manual input adjustment
apparatus 21, the photographic film 200 shall stop automatically when the
inputted image frame comes under the bar code reader 220 whereby necessary
data memorized in the memory 111 could be read out automatically and
instantly.
In case of the comparison of identity of the image frame with memorized
data by means of the frame number or the printing number, too, the
comparison operation may be made either manually or automatically.
Further, in this instance after the comparison, the image frame may be
subjected to photometry (Step S3) and then to printing.
If a modification or correction of an exposure value is found necessary by
and with respect to the test printing, it is advisable to determine a
final exposure amount for future printing with reference to such exposure
amount which is based upon the average density newly obtained by corrected
printing, the exposure correction amount which is stored in the memory,
and the modification or correction value which is found necessary by the
test printing.
Although it has been described that image data of all the negative films
which have been printed once in the photographic printer are to be
memorized in the memory 111, such memorization may be limited only to a
made for test printing, because deviation of a printing from the test
printing shall, specifically and more adversely compared to other printing
cases, induce serious problems including waste of photographic papers,
labors and time as mentioned above. Such memorization would be limited to
those treated for a period of two days at the longest for example so that
old data shall be replaced successively by new data. If it is decided that
there are memorized two identical image frames, one of them memorized more
lately would only be kept in the memory. While it is described above that
an exposure amount based on an average density of an image is obtained by
the scanner photometry, it is within the scope of this invention to obtain
an exposure correction amount by using a monitored image as in the case of
a well-known LATD photometry.
In the present invention method, as described above, an image frame can
always be printed with the same density and without any deviation of
density even when it is printed again with a lag of time, since it is
judged by means of image characteristic values representing structures and
characteristics of the image frame or by means of image frame or printing
numbers thereof, before the printing, if the image frame is identical or
not with any one of image frames which have been previously printed and
data of which have been memorized, and since when it is decided that the
image frame is identical with one of them, the frame is printed on the
basis of an exposure amount which is determined with reference to the data
previously memorized with respect to the image frame.
It should be understood that many modifications and adaptations of the
invention will become apparent to those skilled in the art and it is
intended to encompass such obvious modifications and changes in the scope
of the claims appended hereto.
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