JPH0782206B2 - Color photo printing method - Google Patents

Description

The present invention relates to a color photographic printing method, and more particularly, to an appropriate printing exposure condition (printing condition) of a plurality of film types having different characteristics from the printing exposure condition of a reference film type. The present invention relates to a color photographic printing method capable of automatically determining and printing.

[Conventional technology]

2. Description of the Related Art Conventionally, an automatic color photographic printing apparatus has a slope control function in order to print an overexposed / underexposed negative at a constant density in the automatic color photographic printing apparatus. The reason why this slope control function is necessary is that the reciprocity law failure of the color paper, the mismatch of the spectral sensitivity distribution of the photometric system of the automatic color photographic printer and the spectral sensitivity distribution of each emulsion layer of the color paper, the characteristic curve of the negative film In the shape of.

The above reciprocity failure can be solved by creating color paper with no or less reciprocity failure. Also,
Regarding the above spectral sensitivity distribution, it can be resolved by matching the spectral sensitivity distribution of the photometric system and the spectral sensitivity distribution of the exposure system,
Japanese Patent Publication No. 45-4911, Japanese Patent Publication No. 51-113627, Japanese Patent Publication No.
Japanese Patent Application Laid-Open No. 53-64037 and Japanese Patent Application Laid-Open No. 59-220761 disclose that the spectral sensitivity distributions of the photometric system and the exposure system are matched by using a filter or the like.

On the other hand, depending on the film design concept and the application of the film,
At present, several tens of film types having different characteristic curve shapes are manufactured.
-29641 proposes an electric circuit for approximately linearly correcting the non-linear portion at the upper and lower ends of the film characteristic curve. However, in this case, it is insufficient because the fact that the image is formed in the non-linear portion is not taken into consideration. In addition, how to detect non-linearity and the difference in non-linearity between film types are not taken into consideration.

[Problems to be Solved by the Invention]

By the way, when the spectral sensitivity distribution of the photometric system and the spectral sensitivity distribution of the exposure system match as described above, three film characteristic curves R (red), G (green), and B (blue) are used. Only when the curve of (3) is substantially parallel to the three curves of R, G, B of the specific film type, it is possible to properly print and expose each film type under the printing and exposure conditions of the specific film type. Only in this case, the relationship between the exposure control density value determined from the image density and each image density becomes constant regardless of the film type.

However, in the conventional technique for matching the spectral height distributions, since the shape of the film characteristic curve is not taken into consideration, it is not possible to optimally determine the printing exposure conditions of a plurality of film types having different characteristic curve shapes. There was a problem.

The present invention has been made to solve the above problems, and provides a color photographic printing method capable of automatically determining appropriate printing exposure conditions for film types having different characteristics by considering the film characteristics. The purpose is to

[Means for Solving the Problems]

To achieve the above object, the present invention is based on a standard printing exposure condition for printing an image recorded on a film of a standard film type, and an image recorded on a film of a predetermined film type different from the standard film type. In printing, the image density characteristic of each film type is obtained from a large number of images recorded on the reference film type film and the predetermined film type film, respectively, and the image density characteristic of the reference film type and the image of the predetermined film type are obtained. Compare with the concentration characteristics,
It is characterized in that the standard printing exposure condition is corrected based on the comparison result and printing is performed.

[Action]

In the present invention, the image density characteristics of each film type are obtained from a large number of images respectively recorded on a film of the reference film type and a film of a predetermined film type to be printed different from the reference film type, and the image of the reference film type is obtained. The density characteristics and the image density characteristics of the predetermined film type are compared. This image density characteristic is a film characteristic relating to image density, and the spectral characteristic of the color material of the film, the γ value, the shape of the characteristic curve of the film, and the like can be used.

Then, based on the comparison result, the reference printing exposure condition for printing the image recorded on the film of the reference film type is corrected, and the image recorded on the film of the predetermined film type to be printed is printed. . Further, in the correction of the standard printing exposure condition, for example, when the above-mentioned γ value is used as the image density characteristic, the ratio of the γ value of the predetermined film type to the γ value of the reference film type, the image density of each film type It can be corrected by using the slope control magnification obtained from the ratio, the difference between the γ value of the reference film type and the γ value of the predetermined film type, or the exposure correction amount obtained from the density difference of these film types.

By correcting the standard printing exposure conditions as described above, it is possible to automatically obtain the printing exposure conditions by which the images recorded on the film of each film type can be properly printed.

〔The invention's effect〕

As described above, according to the present invention, it is possible to obtain a printing exposure condition capable of properly printing an image recorded on a film of each film type from a single standard printing exposure condition,
It is possible to print an overexposed / underexposed negative with high quality, and it is possible to obtain an effect that it is easy to manage against characteristic variations because there is one printing and exposure condition.

〔Example〕

A color-added automatic color photographic printing apparatus to which the present invention is applicable will be described below with reference to the drawings. As shown in FIG. 1, a lamp box 10 having a mirror box 18 and a halogen lamp is sequentially arranged below the negative film 20 loaded in the negative carrier and conveyed to the printing section.
A motor is installed between the mirror box 18 and the lamp house 10.
A rotary disk 14 rotated by 16 and an infrared cut filter 12 are inserted.

As shown in FIG. 2, the rotary disk 14 is provided with a disassembling filter including a G filter 15, a B filter 17 and an R filter 19 in the vicinity of its circumference. These G filters 1
5, the B filter 17 and the R filter 19 are, as shown in FIG. 3 (1), arranged in parallel with the white glass 23 coated with the dielectric multilayer film 25 and the R, G, B colored glass 21. Is configured. Here, since the infrared cut filter 12 is always present on the lamp how 10 side, it is thermally stable except immediately after the lamp house 10 is turned on. On the other hand, the G filter 15, the B filter 17, and the R filter 19 are sequentially arranged on the lamp house 10 by rotating the rotary disk 14, so that these filters are inserted between the mirror box 18 and the lamp house 10. Occasionally there is a risk of thermal instability. FIG. 4 (1) shows the characteristics when the rotating disk is rotated in the vicinity of the light source as shown in FIG. 1 by constructing the R filter with only colored glass. As the rotating disk rotates, FIG. The color separation filter surface reaches about 150 ℃ within a few seconds and the relative transmittance fluctuates. Originally, the colored glass filter was 0.15 nm / ° C for the R filter and 0.1 for the G filter.
A wavelength shift of 0 nm / ° C and 0.08 nm / ° C for a B filter is known, and it is not preferable to rotate and use in such a high temperature portion. It is known that the dielectric multilayer film shifts the spectral curve to the long wavelength side under heating, and conversely shifts to the short wavelength side under vacuum. Therefore, under the high temperature as in this embodiment, neither the colored glass filter alone nor the dielectric multilayer film alone can be used. However, in this embodiment, a colored glass filter that shifts to the long-wave side due to temperature fluctuations and a filter coated with a dielectric multilayer film that shifts to the short-wave side due to temperature fluctuations are configured as shown in FIG. 4 (3). Then, Fig. 4 (2)
As shown in, thermal fluctuations are prevented. FIG. 4C shows that a short wavelength R is formed by the colored glass filter (R-64 filter manufactured by Hoya Glass Co., Ltd.) 21 and the dielectric multilayer film 25.
The figure shows how a thermally stable infrared cut filter 12 forms a long wavelength R.

The G filter 15, B filter 17 and R filter
19 may be configured by coating a dielectric multilayer film 25 on the surface of the colored glass 21 as shown in FIG. 3 (2).

Above the negative film 20, a lens 22, a black shutter 24, and a color paper 26 are arranged in order, and the infrared cut filter 12, the filter on the rotary disk 14, the mirror box 18, and the negative filter 20 are illuminated by the lamp house 10. The transmitted light rays are colored paper by the lens 22.
It is configured to image on 26.

A two-dimensional image sensor 28 is arranged in a direction inclined with respect to the optical axis of the imaging optical system and at a position where the image density of the negative film 20 can be measured. The two-dimensional image sensor 28 is a storage photoelectric conversion element such as CCD or MOS, an optical system for forming an image of the negative film 20 on the photoelectric conversion element, and a photoelectric conversion element output to process and output as image information. And a signal output circuit for This signal processing circuit
After converting the output of the photoelectric conversion element into a digital signal, the reciprocal thereof is logarithmically converted and output as a density signal.

The characteristics of the infrared cut filter 12 are as shown by the one-dot chain line in FIG. 5 (3), and the relative spectral transmittance of the three-color photolytic filter for rotary disk is as shown by the solid line in FIG. 5 (3). . The relative sensitivity distribution of the two-dimensional image sensor 28 is as shown by the solid line in FIG. 5 (2), and the spectral sensitivity distribution of the two-dimensional image sensor 28 in the color addition method is as shown by the broken line in FIG. 5 (2). become. The relative spectral sensitivity distribution of color paper is as shown by the solid line in FIG. 5 (1), and the spectral sensitivity distribution of color paper in the color addition method is as shown by the broken line in FIG. 5 (1).

The two-dimensional image sensor 28 is a two-dimensional image sensor.
It is connected to a photometric value memory 30 which stores the density signal output from the sensor 28. The photometric value memory 30 is connected to the film type density storage memory 32 and the photometric value selecting means 38.
The film type concentration storage memory 32 has a film type classification means.
The film type density accumulation memory 32 is connected to the photometric value selecting means 38 and the exposure amount correction value determining means 42 via the image density characteristic determining means 36. The photometric value selecting means 38 is connected to the exposure amount determining means 44 via the exposure control value calculating means 40, and the image density characteristic determining means 36 is connected to the exposure amount determining means 44 via the exposure amount correction value determining means 42. There is. A print condition input means 46 is connected to the exposure amount determining means 44 via a print condition memory 48. The exposure amount determining means 44 controls the motor 16 to rotate the rotary disk 14 to control the exposure amount.

The operation of this embodiment will be described below while explaining each of the blocks shown in FIG.

The film type classifying means 34 classifies the films for each film type as the negative film having the same manufacturer, color material, γ value, base density, photosensitivity and shape of the image density characteristic curve. Is. The film type classifying means 34 is used for a film by detecting a peak value of transmission density with respect to a characteristic wavelength of the negative film, which is a DX code reading device for reading a DX code previously exposed on the side edge of the negative film. It is possible to use a device or the like that reads the characteristics of the existing coloring material. Alternatively, the film type classifying means 34 may be constituted by a keyboard, and the film types may be classified according to the operator's judgment and manually input.

The print condition input means 46 and the print condition memory 48 are
The print conditions of R, G, and B of a reference film type, for example, Super HR100 (trade name, manufactured by Fuji Photo Film Co., Ltd.) are input and stored. At least one of the exposure amount, the exposure time, the filter amount, the light source brightness, the light source voltage, and the slope control value can be used as the printing condition.

The film type concentration storage memory 32 is a film type classification means.
A photometric value memory 30 output is accumulated and stored for each film type classified by 34, for example, Japanese Patent Laid-Open No. 61-267749.
The technique described in the publication can be used. That is, the average negative density is obtained and stored by accumulating the densities of each photometric point, each screen portion, or the entire screen to obtain an average value.

The image density characteristic determining means 36 determines the image density characteristic of the film in accordance with the R, G, and B densities obtained by the film type density accumulation memory 32. An example in which the gradient (γ value) of the image density characteristic curve is used as the image density characteristic of the film will be described below. First, a reference value (for example, G concentration or average concentration of R, G, B (R + G
+ B) / 3 etc.), the characteristic curve of the image density is obtained for each of R, G and B by obtaining the ratio of the R, G and B densities obtained in the film type density accumulation memory 32. FIG. 6 (1) shows a characteristic curve of R concentration with respect to G concentration, and FIG. 6 (2) shows R with respect to (R + G + B) / 3 concentration.
It shows a characteristic curve of concentration.

To determine the image density characteristic of the film from these characteristic curves, for example, as shown in FIG. 7 (1), the gradient γ _{u of the} underexposed portion and the gradient γ _{o of the} overexposed portion are used.
Can be used. Also, as shown in FIG. 7 (2), the average value of the gradients (γ1 + γ2 + γ3) / 3 and FIG. 7 (3)
The gradients γ1 and γ2 shown in can also be used. Although the method of automatically obtaining the image density characteristic using the film type density accumulation memory 32 and the image density characteristic determining means 36 has been described above, both means are omitted and the image density characteristic is stored in advance in the memory (image density characteristic memory). Means) The film type classifying means may read the data from the memory means and input it to the exposure amount correction value determining means 42 and the photometric value selecting means 38.

The exposure amount correction value determining means 42 calculates an exposure amount correction value from the image density characteristic of the reference film type and the image density characteristic of the film type to be printed out of the image density characteristics determined by the image density characteristic determining means 36. In the following, an example will be described in which the γ value determined by the image density characteristic determining means 36 as the image density characteristic and the film type slope control magnification K _ji for correcting the slope control value as the exposure correction value are obtained.

The slope control magnification K _ji for each film type is the γ value (γ _jo ) of the reference film type and the γ value (γ value of each film type.
_ji ) and the following formula.

K _ji = f _j (γ _ji , γ _jo ) ... (1) where j is one of R, G and B, i is a film type, and i = 0 is a reference film type. Also,
F in the equation (1) indicates a function. Therefore, γ in the above equation (1)
_ji indicates the gradient of the i film species, and γ _jo indicates the gradient of the reference film species.

Slope control magnification γ _ji based on equation (1) above
To obtain, underexposure and overexposure are calculated separately. The slope control magnification is expressed by the following equations (2) and (3), for example.

K _ji = a (γ _ji / γ _jo ) ... (2) However, a is a constant of 0 to 2.0, preferably 0.3 to 1.0, and R,
It depends on G and B.

K _ji = (1-b) + b (γ _ji / γ _jo ) ... (3) where b is 0 to 2.0, preferably 0.3 to 1.0, and R is
It depends on G and B.

Therefore, the slope control magnification K _ji can correct the slope control value of the reference film type for each film type as needed. In addition, the slope that determines the slope control magnification is shown in FIG.
The gradient of (3) can be used.

In the above, an example of obtaining a correction value for correcting the slope control value has been described, but the gradient γ _ji and the gradient γ _jo
The exposure correction amount d _i may be obtained from the difference between Further, although an example of obtaining the slope control value and the correction value of the exposure correction amount from the gradient has been described above, the slope control value or the correction value of the exposure correction amount may be obtained using the density ratio or the density difference.

The photometric value selecting means 38 is for selecting a photometric value to be used for the exposure control density value calculation. The photometric value corresponding to a specific color region, for example, a color region including neutral color (gray) and flesh color is stored in the photometric value memory. select. A method for extracting data corresponding to the specific color area will be described below. First, the average negative film concentration R _o , G _o , B _o , D _o = (R _o + G _o + B _o ) / 3
The curve shown in FIG. 8 is prepared for each of R _o , G _o and B _o . Further, in order to extract the data of the area close to the specific color area, the offset amount d ₁₁ , d ₁₂ , d
₂₁ , d ₂₂ , d ₃₁ , and d ₃₂ are defined for each of underexposure, normal exposure, and overexposure, and the regions shown by broken lines in FIG. 8 are defined. Then, the average value D of the photometric values R, G, B =
(R + G + B) / 3 is obtained, and it is determined whether or not the photometric value R for the average value D is included within the broken line in FIG. Similarly, it is determined whether the photometric values G and B are included in the area within the broken line in FIG. Exposure control is selected only when all three photometric values R, G, B are included in the areas defined as shown in FIG. 8 with respect to the average negative film densities R _o , G _o , B _o . Used for calculating the concentration value. Further, the offset amounts d _{11 to} d ₃₂ are preferably changed depending on the film type or the gradient R _o / D _o , G _o / D _o , B _o / D _o .

The measurement value may be selected as follows. That is, the image density characteristic curves described in FIG. 8 for the average negative film densities R _o , G _o , B _o are set as shown in FIG. 9, and the photometric values R, G, B are determined using this image density characteristic curve. R ', G', and B'are obtained by converting into D _o by the method described in JP-A-60-27352. By this conversion, the photometric values having the same color balance as the average negative film are converted into the same R ', G', and B'density. Then, it is determined whether or not these R ', G', and B'are used for the exposure control density value calculation on the chromaticity diagram.

The exposure control value calculation means 40 calculates the density value for exposure control using the photometric value selected by the measurement value selection means 38, and is disclosed in JP-A-61-198144 and JP-A-61-22.
By the method as disclosed in Japanese Patent No. 3731 and Japanese Patent Laid-Open No. 61-232442, the exposure control density value is calculated from the dark density determined based on the classified photometric values. That is, the tenth
As shown in the figure, in step 100, the point corresponding to the specific color area is set as the origin to normalize the density value for each pixel. In the next step 102, R'-G ', G'-B' are calculated using the normalized density values R ', G', B '. In the next step 104, a color area as shown in FIG. 11 is determined for each measurement point from the color coordinate table. Then, the color of the closed area on the color coordinates including the neutral color and the flesh color, or the color of the closed area on the color coordinates including the neutral color and the flesh color (for example, 0 (neutral color in FIG. 11), One, three
A measurement point belonging to the (skin color) area is selected (the above is performed by the photometric value selection means). The density values of the selected measurement points before normalization are added to obtain an average value of R, G, and B, and this average value is used as the exposure control density value. Since this exposure control density value does not include a density value that causes a color area, it can be used for determining the exposure amount without lowering the degree of color correction.

The exposure amount determining means 44 is calculated by the print condition of the reference film type stored in the print condition memory 48, the exposure control density value calculated by the exposure control value calculating means 40, and the exposure amount correction value determining means 42. The exposure amount is determined using the exposure amount correction value. When the slope control magnification is used as the exposure amount correction amount, the exposure amount is calculated according to the following formula.

logE _ji = C _i · K _ji · S _jo (D _ji −D _jON ) ＋ F _j ＋ d _ji (4) However, E _ji : Exposure F _j : Color paper, constant determined by automatic color photoprinting device d _ji : Exposure correction amount based on the image contents D _jON : Exposure control density value of the reference image of the reference film type (F _o ) D _ji : i Exposure control density value of the film type C _j : Color collection coefficient (≈1.0) j: One of R, G, B i: Film type (however, i = 0 is the reference film type) S _jo : Slope control coefficient (= 0.5 to 2.0) K _ji : Slope control magnification (= 0.5 to 2.0) Specifically, the above equation (4) becomes the following equation (5).

Although an example of calculating the exposure amount using the correction value calculated by the exposure amount correction value determination means has been described above, this exposure amount correction value determination means is omitted and the image density characteristic determination means is directly controlled by the exposure control. The exposure control density value may be directly calculated by connecting to a value calculation means and using the image density characteristic difference. That is, the R concentration of i film type Fi
Since Di has the relationship shown in FIG. 12 with respect to the concentration of the reference film species F _o , when the concentration Di is smaller than the average concentration D _N , it is converted as shown in the following equation (6).

D ′ _i = D _N −K (γ _jo / γ _ji ) (D _N −D _i ) ... (6) where j = R, γ _jo is the gradient of the reference film species, γ _ji is the gradient of the i film species, K is a constant (may be changed depending on the film type).

Then, the value Di ′ converted by the above equation (6) is used as the exposure control density value of the i film type Fi. In general, the above equation (6) can be expressed as the following equation (7).

D ′ _ji = g _j (γ _ji , γ _jo , D _ji ) (7) As described above, when Di <D _N , the characteristic curve of the i-film type is corrected by the above equation (6). The characteristic curve of the reference film type and the characteristic curve of the i film type are substantially parallel to each other, so that the i film type can be printed according to the printing conditions of the reference film type. In the above, R and B are corrected centering on G, but (R +
You may make it correct on the basis of G + B) / 3.

Next, a white color reduction type automatic color photographic printing apparatus to which the present invention can be applied will be described. Incidentally, in FIG. 13, parts corresponding to those in FIG.
In this white color reduction type automatic color photoprinting device, a dimming filter is installed between the lamp house 10 and the mirror box 18.
A 60 and a color light regulation filter 62 are arranged. As is well known, the light control filter 60 is composed of three filters, a Y (yellow) filter, an M (magenta) filter, and a C (cyan) filter. Also, the color light regulation filter 62 is
A BG regulation filter a for regulating the B light long wave and the G light short wave,
GR control filter b for controlling G long wave and R short wave,
It is composed of four filters, an ultraviolet cut filter c and an infrared cut filter d.

In this color light regulation filter 62, B light is formed by the combination of the ultraviolet cut filter c and the BG regulation filter a, and G light is formed by the combination of the BG regulation filter a and the GR regulation filter b, and the infrared cut filter d is formed. R light is formed in combination with the GR regulation filter b. The transmission characteristic of the color light regulation filter 62 is as shown in FIG. 14 (3).

The following filters are used for the two-dimensional image sensor. That is, a B filter having a transmittance long-wave end in the absorption band of the BG control filter a, a G filter having a transmittance short-wave end in the absorption band of the BG control filter a and a transmittance long-wave end in the absorption band of the GR control filter b. An R filter having a transmittance short-wave end in the absorption band of the filter or the GR regulation filter b is used. The transmittance characteristics of the R, G, and B filters are as shown by the solid line in FIG. 14 (2), and the transmittance distribution when combined with the color light regulating filter 62 is shown by the broken line in FIG. 14 (2). Like The R, G, and B filters are used by arranging the respective colors in a mosaic pattern such as Japanese Patent Application No. 61-22155, a stripe pattern, or a checkered pattern. Further, the spectral sensitivity of the color paper when corrected by the color light regulation filter 62 is shown by a broken line with respect to the spectral sensitivity (solid line) of the uncorrected color paper, as shown in FIG. 14 (1). It is almost the same as the spectral sensitivity distribution of the photometric system shown in FIG. 14 (2).

Then, after the spectral sensitivity distributions are matched as described above, photometry is performed using the color light regulating filter, and the printing conditions of the reference screw film type are corrected as described above, and printing is performed using the Y, M, and C filters. As a result, it is possible to satisfactorily print the film types having different image density characteristics by the white color reduction method. The present invention is naturally applicable even if the photometric system and the exposure system are separately arranged in the white light subtractive color printing method.

As described above, according to the present embodiment, the print conditions of the reference film type can be improved by correcting the print conditions of the reference film type according to the image density characteristic difference. It is possible to print with high quality from underexposure to overexposure of various films. In addition, since various films are printed based on the print conditions of the standard film type, even if various characteristics of the negative developing machine, the negative film, the automatic color photographic printing apparatus, etc. are changed, one print condition, that is, the standard. Since only the print conditions of the film type need to be managed, proper management can be easily performed. In addition, since appropriate conditions are automatically corrected for each film type, appropriate prints can be produced for various films.

In the present invention, a method for automatically determining the print condition correction amount or the corrected print condition for each film type based on the reference film type print condition and printing, and a print condition for each film type A switch may be provided so as to select a method of determining a modified print condition for the reference print condition based on printing. In this case, the modified print conditions are IC card and LS
It may be stored in the I card and read from the film type classification means. As described above, various combinations of conventional methods can be considered for the present invention, but these are merely different applications of the present invention.

[Brief description of drawings]

FIG. 1 is a schematic view showing a color-adding type automatic color photographic printing apparatus to which the present invention is applicable, FIG. 2 is a plan view of the rotary disk of FIG. 1, and FIG. 3 is a schematic view of the filter of FIG. 4 (1), (2), and (3) are diagrams showing the characteristics of the R filter, and FIGS. 5 (1), (2), and (3) are color papers in the addition method and a two-dimensional image sensor. FIG. 6 is a diagram showing the spectral sensitivity distribution of FIG. 6, FIG. 6 is a diagram showing an example of an image density characteristic curve,
7 (1), (2), and (3) are diagrams for explaining the image density characteristic, FIG. 8 is a diagram showing a region for selecting the photometric value, and FIG. 9 is for converting the photometric value. A curve diagram, FIG. 10 is a flow chart for obtaining the exposure control density value, FIG. 11 is a diagram showing a color region, and FIG. 12 is a diagram showing R characteristic curves of two film types. FIG. 13 is a schematic view showing an automatic white light color-reducing type color photographic printing apparatus to which the present invention can be applied. FIGS. It is a diagram showing distribution and the like. 12 …… Infrared cut filter, 14 …… Rotating disk, 18…
… Mirror box, 20 …… negative film, 26 …… color paper.

Claims (1)

[Claims] 1. An image recorded on a film of a predetermined film type different from the reference film type is printed on the basis of a reference printing exposure condition for printing an image recorded on a film of the reference film type, The image density characteristic of each film type is obtained from a number of images recorded on the film of the reference film type and the film of the predetermined film type, and the image density characteristics of the reference film type and the image density characteristics of the predetermined film type are compared. A color photographic printing method characterized in that the standard printing exposure condition is corrected and printed based on a comparison result.