JPH0481781B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention also measures the reflection density of a photographic print using a photoreceptor for measuring film transmission density, and it is possible to easily set conditions for producing an optimal finished print by correcting the exposure conditions. Related to photo printing equipment. [Prior Art] In order to consistently produce good quality color prints using a printer, it is necessary to accurately set the exposure conditions of the printer section. For this reason, standard exposure conditions are set when the printer is installed, but if you use color paper with a different emulsion number, replace the printer lamp, replace the processing solution, or change the season, the photos may change. When the content changes from having many colors to having fewer colors or vice versa, it is necessary to correct and reset the exposure conditions. To correct the exposure conditions, we used a standard negative film, a so-called eyeball negative, which was a gray subject photographed at three levels of exposure: underexposure, normal, and overexposure, and a test print that was printed and developed from this eyeball negative. The density is compared with the density of a standard reference print that has been printed and developed from this eyeball negative in advance and corrected. The principle of this correction will be explained using the simplest exposure calculation formula. This exposure calculation formula is shown in the following formula (1). However, C, M, and Y represent the three primary colors in the subtractive color method.

[Table] Underslope value of 〓
D _CO , D _MO , D _YO ...Density value for exposure control, for example, the exposure amount E _R of red (R) is determined by the following formula E _R = E _N・10D _CO ... (2) Here , E _N is the exposure amount of the reference negative (normal) of the negative type and is a constant. The exposure amounts of green (G) and blue (B) are similarly determined from D _MO and D _YO . Now, if the minute density value change and γ value of cyan on color paper are ΔD _PC and γ _C , then ΔD _PC = γ _C・Δl _pg (E _R ) ...(3), and from equations (2) and (3), the following is obtained. Equation (4) is obtained. ΔD _PC = γ _C・ΔD _CO・l _pg ( _EN ) ...(4) From this, ΔD _CO can be found by back calculation.
Assuming that the difference between the density value of the normal test print of the reference negative and the density value of the reference print is ΔD _PC , ΔD _PM , and ΔD _PY , for example, if ΔD _PC is set to zero, the equation (1) above is of the calculation result
When D _CO becomes D _CO ′=D _CO −ΔD _CO ……(5), it just cancels the previous ΔD _PC and the difference becomes zero. Which constants are changed to do this depends on which density reference negative the negative is. Similarly to equation (5), D _MO ′=D _MO −ΔD _MO ...(6) D _CY ′=D _YO −ΔD _YO ...(7) is obtained, and the conditions are set as follows. In the case of normal negatives, the measured normal negative densities D _C , D _M , D _Y are calculated as D _NC , D _NM , D _NY of the negative type channel.
Store in. A print of the normal negative is made, and from the difference between its density value and the density value of the reference print, the correction value ΔD _CO is calculated using equations (5), (6), and (7) above.
Determine ΔD _MO and ΔD _YO and store them in B _NC , B _NM , and B _NY of the negative type channel. In the case of an overnegative (performed after the above), make a print of the overnegative, and use the difference between its density value and the density value of the reference print to calculate D _CO ′ and D _MO using (5), (6), and (7) above. ′, D _YO ′, and find the overslope value C _CO , which makes the calculation results D _CO , D _MO , and D _YO of the above equation (1) become these values.
C _MO and C _YO are calculated backwards and stored in C _CO , C _MO and C _YO of that negative type channel. Obtain C _CU , C _{MU ,} and C _YU in the same way as in the case of the under negative (performed after), and store them in C _CU , C _MU , and C _YU of the negative type channel. Conventionally, in the above methods, the density value was measured manually and the negative type channel was manually designated. Note that the negative channel internal constants are tabulated as follows.

[Table] As shown in FIG. 6, a photographic printing apparatus generally arranges a negative film between a lens 10 and a light source 12, and forms an image on photographic paper 14 for exposure. The exposure time is determined by measuring the film transmission density with a light receiver 38 which is disposed outside the exposure path on the photographic paper 14 side of the negative film and facing the negative film. In order to measure the reflection density value of a photographic print from an eyeball negative using a photoprinting apparatus with such a structure, and to correct the printing conditions based on the difference from the opposite density value of the reference print, it is necessary to separately measure the reflection density value. It would be appropriate to include a meter, but this would be expensive. Therefore, with this structure as it is, photographic paper 16 cut into strips with the width of the negative film is inserted into the negative carrier 18 where the negative film should originally be set, the transmission density is measured, and this is used as a reference print. There is also a structure in which the exposure conditions are corrected based on the difference between the two (see Japanese Patent Laid-Open No. 10943/1983). In this case, the transmission density value also includes the density value depending on the thickness of the paper that is the base of the photographic paper, and although it is difficult to say that it is the exact reflection density value of the print, it is possible to calculate the difference from the reference print. , by canceling this out and linearly converting the measured value, it can be used to correct the exposure amount to some extent. [Problems to be Solved by the Invention] However, the base of photographic paper is not only not transparent but also has a very high density, so it is difficult to accurately measure the density of a photographic print by transmission density. Furthermore, it is laborious to cut the finished photographic print into strips the width of the negative film, and the work efficiency is poor. In consideration of the above facts, the present invention provides a photographic printing apparatus that can also measure the reflection density of photographic paper using a photoreceptor for film transmission density photometry, and that can improve the workability of correcting exposure conditions. is the purpose. [Means for Solving the Problems] In order to solve the above problems, in the photographic printing apparatus according to the present invention, a reflecting surface (including a mirror surface and a diffusely reflecting surface) is provided on the shutter surface, and the shutter surface is provided outside the exposure path. A light receiver for measuring the transmission density from the film to be printed is disposed toward the reflective surface when closed, and a photographic print mounting section can be disposed between the reflective surface and the light receiver. The exposure conditions are corrected by measuring the reflection densities of each of the photographic print and the reference print under the current settings, and the exposure amount correction means calculates an exposure condition correction value from the difference between them. The lens may be disposed on either the film side or the photographic paper side of the shutter. [Function] According to the present invention, when measuring the integrated transmission density of a film (eyeball negative), by closing the shutter, the transmitted light is reflected by the reflective surface and received by the light receiver. An integrated transmission density is calculated according to the amount of light received by the light receiver, and a printing process is performed based on the calculation result (that is, a printing process with the current settings). Thereafter, the developed photographic print is placed on the photographic print loading section. The light from the light source that passes through the lens is reflected by the photographic print, enters the light receiver, and is received. Thereby, the reflection density of the photographic print can be measured. In the same way, the reflection density of a reference print (printed under appropriate conditions) printed from an eyeball negative is measured. The exposure condition correction means calculates the exposure condition correction value from the measured print density under the current settings and the reference print density, and corrects the exposure condition calculated based on LATD to create the optimal print. Reset the conditions. Thus, in the present invention, the LATD of the film is
Since the reflection density of the photographic paper can also be measured using a photodetector for measuring the , a complicated configuration is not required and the exposure conditions can be easily corrected. [Embodiment] An embodiment of the photographic printing apparatus according to the present invention will be described with reference to the drawings. As shown in FIG. 1, an image on a color film 13 placed between a lens 10 and a light source 12 is formed onto photographic paper 14 and exposed. Between the light source 12 and the color film 13, cyan, magenta, and yellow color correction filters 20, 22, and 24 and cut filters 26, 28, and 30 corresponding to red, green, and blue are disposed. The cut filters 26, 28, 30 are each driven by a rotary solenoid group 32. A shutter 3 is located between the lens 10 and the photographic paper 14.
4 is provided and is driven by a rotary solenoid 36. The shutter 36 is opened against the biasing force of a return spring (not shown) by energizing the rotary solenoid 36.
By demagnetizing it, it is closed by the biasing force of the return spring. A reflecting surface 37 (a mirror surface or a diffusely reflecting surface) is provided on the lower surface of the shutter 34 (the surface on the film 13 side). Three light receivers 38 corresponding to red, green, and blue color light are provided on the outer periphery of the lens 10 toward the center of the reflective surface 37, shielded from external light. A photographic paper loading section 40 is provided below the shutter 34. This photographic paper loading section 40 is, as shown in FIG.
Rails 42 and 44, which are parallel to each other, are arranged outside the exposure path with these grooves 42A and 42B facing each other, and both sides of an insertion tool 46 are removably fitted into the grooves 42A and 42B. There is. Insertion tool 46
A rectangular upper plate 48 and a lower plate 50 are connected at one end with a hinge 51. An opening 50A is provided in the center of the lower plate 50. Lower plate 5
A U-shaped frame member 52 formed of a permanent magnet is fixedly opposed to the edge of the frame member 0, and is used for positioning the photographic print 16 and attracting the upper plate 48. The apparatus constructed as described above is controlled by a microcomputer 58 equipped with an input/output interface, as shown in FIG. The microcomputer 58 is configured to receive signals from the light receiver 38, and calculates the transmission density of the color film 13 and the reflection density of the photographic print 16 (see FIG. 2) loaded on the photographic paper mounting device 40. In addition to measuring the shutter 3
It is now possible to check the opening/closing operations of 4. When an abnormality in the shutter 34 is detected, the microcomputer 58 activates the buzzer 6.
0 and a lamp 62. These alarms are activated by reset switch 64.
It can be reset by a signal from. The microcomputer 58 also has a keyboard 66.
The exposure amount can also be corrected based on input signals from the camera. Next, the operation of this embodiment configured as described above will be explained. First, the film transmission density of the color film 13 will be explained. As shown in FIG. 3 (positions corresponding to the color film 13, photographic paper 14, and reflective surface 37 are indicated as 13P, 14P, and 37P, respectively), the light on the reflective surface 37 is out of focus. That is, points A, B, and C of the image are respectively focused on points A', B', and C' of the photographic paper 14, but
The reflective surface 37 has widths l, m, and n. Furthermore, these widths l, m, and n overlap each other.
Therefore, by photometering such out-of-focus light, it is possible to measure the density of the averaged film image. Therefore, the measured concentration is
It is possible to measure the film transmission density with sufficient accuracy for each of the colors cyan, magenta, and yellow with one photoreceiver 38, regardless of the position (orientation) of the photodetector 8. Next, a flow chart of the control of the microcomputer 58 shown in FIG. 4 will be explained with reference to the time chart shown in FIG. In addition, for example,
(Step 100) is abbreviated as (100). Further, for the sake of simplicity, one light receiver is used as a representative of the three light receivers, and control of the cut filters 22, 24, and 26 is also omitted. After waiting for the preparation for opening the shutter to be completed (100), the amount of light received is read from the light receiver 38 (FIG. 5A), and this value is set as E (102). Next, timer X is started (104) and rotary solenoid 36 is turned on (fifth
(Fig. b) to open the shutter 34 (106). Next, after waiting for τ msec (a time slightly longer than the time required for the shutter 34 to be completely open, for example 30 msec) to elapse (108), the amount of light received from the light receiver 38 is read again (FIG. 5C). Let this value be ε (110). This ε is an offset value. I=E-
Find ε (11 2) and correct the amount of received light. This allows the light receiver 3 to change as the ambient temperature changes.
Even if the offset value of 8 changes, the amount of received light can be read accurately. Next, if I>δ (δ is a constant), that is, the operation of the shutter 34 is normal (114), the shutter open time (time from solenoid on to off) T is calculated from the value of I (116). . The value of this T is
This is sufficiently longer than the processing time of steps 108-116. Next, after waiting for the time Tmsec started in step 104 to elapse (118), the rotary solenoid 36 is turned off (120). Then, the process returns to step 100 and repeats the above process. In step 114, if I≦δ, that is, the difference between E and ε is less than the fixed value δ, it is considered that the shutter 34 is not fully open, and the buzzer 60 is sounded and the lamp 62 is lit to stop the shutter 34 from operating. Inform the operator of the abnormality (122). Next, after waiting for the operator to confirm this and turn on the reset switch 64 (124), the buzzer 60 and lamp 62 are turned off (126). Then, the process returns to step 100 at the beginning. In this way, abnormalities in shutter operation can be easily detected. In fact, in step 116, the cutting time of the complementary color by the cut filter is also calculated, and furthermore, in step 118, the cut filter is also controlled. Also, when the shutter is open, the receiver 3
In consideration of the small amount of light received by the
106, a small value Δ proportional to the luminous intensity of the light source 12
may be further subtracted from E. This Δ
may be calculated from an empirical formula of the value of ε for the value of E that is read each time. Next, a procedure for correcting printing conditions will be explained. As shown in FIG. 2, the insertion tool 46 of the reference splint 16 is inserted into the grooves of the rails 42 and 44 with the image plane facing downward. This reference print 16 is produced by printing the color film 13 on which the reference original image is printed onto photographic paper 14 when the photographic printing device is in its optimum condition. Next, by operating the keyboard 66, the light receiver 38 measures the three-color reflection print density X (=consisting of the three values D _CR , D _MR , and _DYR ) of the reference print 16 . Next, instead of a reference print, a photographic print 16A made on the eyeball negative under the current conditions of the photographic printing apparatus (including development processing) is placed in the photographic paper loading section 40 in the same manner as described above.
Attach to. Next, operate the keyboard 66 and use the light receiver 38 to check the reflection print density Y of the current print 16A.
(=D _C , D _M , D _Y ). The microcomputer 58 calculates an exposure amount correction value F (X, Y) from the differences ΔD _C , ΔD _M , ΔD _Y between the reflection print density values X and Y.
Calculate. The procedure is as described below in equations (5), (6), and (7) above. It becomes possible to produce optimal prints under the new conditions created by this new correction. In addition, instead of using a color film with a negative image on it, the color correction filters 20, 22, and 24 are activated to create a reference light, and this reference light is exposed to photographic paper and a photographic print processed by photographic paper is mounted on the photographic paper. By attaching it to the unit 40 and measuring the density of the reflective photographic paper, it is possible to measure the state of the photographic print under the current conditions. Even if this measured value is compared with a predetermined value stored in advance or a value measured by attaching a reference splint (obtained in the same manner under optimal conditions) to the photographic paper loading section 40, the exposure A quantity correction value can be calculated. By resetting the photoprinting device based on this exposure condition correction value, optimal prints can be obtained under the new conditions. [Effects of the Invention] The photographic printing apparatus according to the present invention has a simple configuration in which a photographic paper loading section is disposed between a reflective surface and a photoreceiver, and the photographic paper can be measured using a photoreceptor for film transmission density photometry. Reflection density can also be measured, which has the excellent effect of improving workability in correcting exposure conditions.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention, FIG. 2 is a perspective view of a photographic paper loading section, FIG. 3 is an explanatory diagram for measuring film transmission density, and FIG. 4 is a flow chart showing a control flow. FIG. 5 is a time chart corresponding to the control flow described above, and FIG. 6 is a schematic diagram showing a conventional photographic printing apparatus. 12...Light source, 13...Color film, 14
... Photographic paper, 34 ... Shutter, 37 ... Reflective surface, 38 ... Light receiver, 40 ... Photographic paper loading section, 5
8...Microcomputer.

Claims (1)

[Claims] 1. A reflective surface provided on the film side surface of the shutter, and a reflective surface provided outside the exposure path facing the reflective surface when the shutter is closed to measure the transmission density from the film to be printed. a photographic print mounting section that can be inserted into and taken out of the exposure path and placed between the reflective surface and the light-receiving surface when inserted into the exposure optical path; and a photo print mounting section for printing the condition setting film with the current settings. Both the photographic print and the target standard finish print are placed on the mounting section, the light receiver receives the reflected light of each of these prints, calculates the reflection density value, and calculates the difference between them. A photographic printing apparatus comprising: an exposure condition correction means for calculating an exposure condition correction value from the above.