JPH0512694B2 - - Google Patents

Description

[Detailed description of the invention]

(Technical Field of the Invention) The present invention relates to a photographic printing machine that can efficiently and easily determine the amount of printing exposure. (Technical background and problems to be solved) The determination of the printing exposure amount for color film is usually
This is done using LATD (all-screen average transmitted density). However, in reality, only about 70% of the exposure amount determination using LATD is satisfactory, and the operator must use the negative film prior to LATD photometry (before exposure using the preliminary inspection device or the exposure aperture surface of the printer). Observe the relationship between the main subject and the background and the pattern you have learned from experience.
A correction exposure amount (also referred to as an exposure correction amount, etc., usually based on a density key, color key, function key, color correction key, etc.) for LATD exposure is determined, and the exposure is performed by adding the two. FIG. 1 shows an example of the relationship between the density correction key and the corresponding exposure amount. Normally, by changing one density correction key, 20
The exposure amount is set to change by %. However, this method requires long experience and takes several years to become proficient, the print quality obtained tends to vary between individuals or due to fatigue, etc., and there are major restrictions on working conditions such as night work. There are some drawbacks. Also, after long training, I changed jobs,
There are drawbacks, such as the loss of experience upon retirement, and the reality is that a way out of this method is being sought. As a solution to this problem, an automatic judgment method has been proposed in which the film screen is divided into small pixels and photoelectrically scanned, and the exposure amount is determined by analyzing the resulting density values and combining the data. However, with such fully automatic correction, it is not possible to obtain sufficiently satisfactory quality for all prints. Furthermore, in Japanese Patent Application Laid-Open No. 150336/1984, the density area and overexposure/underexposure are identified and their classification information is manually stored, and when the average density is high, the minimum density of the shadow area is determined using this classification information.
When the average density is low, the maximum density of each highlight portion is determined to determine the exposure amount. That is, by specifying the density area through visual judgment, when the average density is high, it is assumed that there is a subject in the shadow area, and the exposure amount is determined at the lowest density. However, when the average density is high, it cannot necessarily be said that there is a subject in the shadow area, and even if there is a subject in the shadow area, determining the exposure amount based on the lowest density will result in a big error. This is because the minimum density is often equal to the fog density of the image and is a small value that is relevant to the subject matter. In addition, in the inspection device disclosed in Japanese Patent Application Laid-open No. 52-62428, the circuit is switched by pressing a button to rotate the film image in the reverse position or vertical position by 90° or 180° and return to the normal position by visual judgment. That's what I do. However, this method does not determine the feature amount in relation to the subject, but simply rotates the object to bring it to the correct position. Furthermore, it is already known to predict the density correction amount based on scanning data, visually judge it, and correct the automatic judgment result (Japanese Patent Laid-Open No. 48-98821, Japanese Patent Laid-Open No. 52-62429, etc.). This method has drawbacks such as requiring two determinations: determining whether correction is necessary or not, and determining the amount of correction, and requires skill and does not improve the pass rate or throughput. In particular, it is extremely difficult to predict the results of complicated automatic determination operations. In order to improve the correction amount judgment, we have added scene type information (e.g. strobe, open scene, snow, etc.) for scenes where automatic judgment is not good.
It is conceivable to visually determine the amount of time and then correct the automatic determination result by a predetermined amount depending on the scene type. However, in automatic judgment, strobe negatives generally tend to have insufficient density, but since there are many normal and too dark strobe negatives, over-correction may cause problems. Also,
The above-mentioned scene type information has drawbacks such as the fact that scene definitions tend to vary from person to person and that it is necessary to assume a large number of scenes. For example, when talking about a strobe scene, it is better to think of completely different types of scenes when the background is a white wall, when the background is furniture, when the background is dark, and when the background is close-up. The cause of this is
Based on the lack of information about the subject matter. Here, as a result of investigating the deviation from the optimal corrected exposure amount between a large number of experts and non-experts, we found that even among experts there is considerable variation in patterns and between individuals. About 98% of the judgments are based on the optimum corrected exposure amount (0%), and the variation is within ±50%, whereas for non-skilled people, the variation is up to about ±70%. Furthermore, Figure 2 is
Regarding those requiring increased exposure correction for LATD exposure, the characteristics indicate an expert and the characteristics indicate an unskilled person. In addition, both skilled and unskilled people tend to be short of the optimal corrected exposure, but the shortfall is larger for unskilled people, and increasing the corrected exposure is more likely to cause variation than decreasing it. There is a tendency to say that it is easy. As described above, the conventional automatic judgment method by inputting visual judgment information is based on the premise that the automatic judgment section will make the judgment automatically, and the only way to do so is to input the correction amount for the automatic judgment as an auxiliary in case of inconvenience. Therefore, its effectiveness is limited. In addition, the visual judgment information is a negative film pattern and does not include density information of the main part or has only a very small amount of that information, so the visual judgment information has little effect.
The drawback is that the improvement in yield obtained is small.
As described above, it can be said that the fully automatic determination and the assistance of the fully automatic determination and the visual determination information have not yet reached the level of quickly producing high-quality, low-priced prints at present. In addition, in small photo labs, it is more important to have a method that allows even slow or inexperienced workers to consistently produce prints of high quality and a high pass rate.Therefore, a new printing method based on cooperation between humans and machines is more important. Proposals are requested. Furthermore, in the case of a scene where, for example, a small person in front of a shrine or temple is illuminated by spotlight, there is a need for the camera to have the feature of being able to make detailed exposure decisions by correcting the density correction key. (Objective of the Invention) As described above, the object of the present invention is to enable even an unskilled person or a beginner to obtain a high print pass rate by operating the automatic judgment section, and to enable even an experienced person to obtain a high print pass rate by operating the automatic judgment section. More importantly, it is possible to print with high quality and a high pass rate. Another object of the present invention is to provide a photoprinting machine that reduces fatigue during visual judgment work and improves throughput. (Means for Solving the Problems) The present invention relates to a photoprinting machine, and the above-mentioned objects of the present invention include a photometric section for photometrically measuring a negative film; characteristic value detection means for determining characteristic values such as maximum density and minimum density; exposure amount determining means for determining a basic exposure amount based on the average density; and an input for inputting a judgment result regarding the density based on visual judgment of the negative film. a key means, a correction amount conversion means for calculating an exposure correction amount according to the input information from the input key means, and selecting one of the exposure calculation formulas according to the input information and substituting the characteristic value. a correction amount determining means for determining an exposure correction amount; a selection means for selecting whether to use the correction amount conversion means or the correction amount determining means; This is achieved by providing a printing exposure amount determining means that determines the printing exposure amount by adding it to the basic exposure amount, and an exposure control section that controls the exposure according to the printing exposure amount. (Operation of the Invention) In the present invention, a correction amount is given to the basic exposure amount obtained by average density photometry such as LATD by using a density correction key, a dedicated key, or a combination thereof with a selection switch. The correction amount is calculated using a predetermined calculation formula in response to each key input. Since the key input is made according to the classification of the negative film based on the visual judgment of the negative film, even beginners can print with high quality and a high pass rate. (Embodiment of the Invention) FIG. 3 shows an example of the configuration of a photoprinting machine according to the present invention, in which a negative film 1 is mounted on a predetermined print section and is irradiated with a light source 3 through a mirror box 2, and the light transmitted through the negative film 1 is irradiated with a light source 3 through a mirror box 2. The light passes through a lens system 4 and a shutter 5 and is imaged onto photographic paper 3. Further, a color dimming filter 7 is disposed between the mirror box 2 and the light source 3, and the amount of light from the light source 3 is detected by a sensor 3A.
Characteristic values such as LATD, maximum density, and minimum density are determined by the R (red) of the photometry section 8 disposed around the lens system 4
Detected by scanning G (green) and B (blue) three color sensors, light intensity signal EM and photometric data
Each CS is input to the control unit 10. moreover,
The photographic paper 6 is wound around a reel 6A, and the printed photographic paper 6 is wound around a take-up reel 6B via a drive section 20. The shutter 5 is controlled by a shutter control section 21 to perform exposure. The lens system 4 is focused for imaging by the focus adjustment section 22, and the filter 7 is controlled via the filter control section 23.
The light sources 3 are each controlled via a light quantity control section 24, and each of these sections 20 to 24 is controlled by a control section 10. A keyboard 30 is connected to the control unit 10, and as shown in FIG. 4, the keyboard 30 includes a density correction key 31 which is operated to visually judge the negative film 1 and adjust the print density, and a density correction key 31 which will be described later. A selection switch 32 is provided for selecting one of two control methods: normal density correction (hereinafter referred to as normal correction) or classification correction. The configuration of the portion of the control section 10 related to exposure control is as shown in FIG.
Density key information from 1 (for example, "-5", "-
4", ..., "-1", "0", "+1", ..., "+
9”) Selection signal from DK and selection switch 32
SL is input, the photometry data CS from the photometry section 8 is inputted to the characteristic value detection section 15, and the detected characteristic value
CV is the exposure amount determining unit 13 and the exposure calculation formula determining unit 1
4 is input. The characteristic value CV is a known screen average density, maximum density, minimum density, etc. When normal correction is selected by the selection switch 32, the density key information DK is output as is from the control method selection section 11 and inputted to the conversion section 12, and the correction amount CM converted by the conversion section 12 is sent to the exposure amount determination section 13. The determined exposure amount EX1 is inputted to the exposure control section 16 together with the characteristic value CV. When classification correction is selected with the selection switch 32, the input density key information
Convert DK to classification information DKA and input it to the exposure calculation formula determination section 14, select a plurality of exposure calculation formulas prepared in advance, calculate the exposure amount EX2 together with the characteristic value CV, and input it to the exposure control section 16. do. Exposure control section 1
6 controls the light amount control section 24 and/or the shutter control section 21 and/or the filter control section 23 according to the input exposure amount EX1 or EX2, and controls the light amount of the light source 3,
Opening time of shutter 5, color dimming filter 7
The amount of opening is controlled. Note that the selection switch 32 may be operated manually or automatically. The density key information may be obtained using the density correction key 31 as described above, or a dedicated key for correction, that is, for selecting one of the exposure calculation formulas, may be provided separately. Further, instead of inputting the density key information using the keyboard 30, the density key information may be input using an information reading device using a correction key information recording medium (eg, paper tape, magnetic tape, etc.). In this case, for example, method selection information can be recorded as input tip information of the paper tape. In such a configuration, first select switch 3
The operation when normal correction is selected in step 2 will be explained. In this case, the photometric data CS obtained by scanning in the photometric section 8 is input to the characteristic value detection section 15, and the characteristic value CV necessary for determining and correcting the exposure amount is inputted to the characteristic value detection section 15.
is calculated and input to the exposure amount determining section 13 and the exposure calculation formula determining section 14. Then, the operator visually judges the negative film 1 and sets the correction exposure information in 15 steps (in this example, it is 15 steps, but Input the density key information DK using the density correction keys 31 (the number is arbitrary). The density key information DK thus input passes through the control method selection section 11 as it is and is inputted to the conversion section 12, where it is converted into a correction amount CM using the following conversion formula, for example: CM=K ^DK (1). Here,
The density key information DK is a value between "-5" and "+9", where a positive value indicates an increase in exposure, a negative value indicates a decrease in exposure, and "0" indicates that the main part and background are different. This shows a standard negative with similar density. Further, the constant K represents the degree of change in exposure amount, and is set to "1.20" for a change of 20%, for example. The correction amount CM obtained by the above equation (1) in the conversion section 12 is input to the exposure amount determination section 13, and the characteristic value is
The final exposure EX1 is obtained by multiplying the basic exposure EF calculated by CV (for example, LATD by the photometer 8) as follows, for example: EX1=EF·CM (2). The exposure amount EX1 thus determined is input to the exposure control section 16, and the light source 3 and/or shutter 5 are controlled to print the negative film 1. Next, the operation when classification correction is selected by the selection switch 32 will be explained. In this case, as in the above-mentioned normal correction, first, the negative film 1 is divided into many small areas and scanned to obtain characteristic values CV, and the negative film 1 is classified by visual judgment by the operator. 2. Operate the density correction key 31. In this case, the density key information entered during the normal correction above
You may use DK as is. In other words, the density key information entered for density correction
DK is used as is for classifying negative film 1. The density correction key information DK is converted into a classification signal DKA according to a predetermined correspondence relationship.
For example, as shown in FIG. 5A, the density correction key information
DK's "-5" key to "-1" key to DKA1,
“0” key goes to DKA2, “+1” key goes to DKA3,
“+2” keys and above are converted to DKA4. In this way, the density correction key information DK is converted into another code and used as the classification signal DKA. Further, the density correction key information DK may be used as it is as the classification signal DKA. The negative film 1 may be classified based on visual judgment information or by including the characteristic value CV obtained by scanning. After this classification, the control method selection unit 1
With the classification signal DKA output from 1, one of the calculation formulas for determining the exposure amount set in advance in the exposure calculation formula determination section 14 is selected, and the characteristic value CV is used with this selected calculation formula. Determine the exposure amount. In addition, the classification of negative film 1 requires at least 60% in order to perform high-speed processing with a high pass rate even for non-skilled people.
With an exposure change rate of more than 100% (preferably 100% or more),
It is preferable to classify them into 6 types or less (preferably 4 types or less). In addition, the calculation of the exposure calculation formula determining unit 14 includes:
For example, JP-A-54-28131 and JP-A-52-
A known arithmetic expression such as that shown in Publication No. 23936 may be used, or the coefficients of one arithmetic expression preset by the classification signal DKA and some of the characteristic values to be used may be made different. May be used. That is, the images are roughly classified based on the density key information DK by visual judgment, and the final exposure amount EX2 is determined by calculating an accurate exposure amount using the scanning characteristic value CV. The arithmetic expression selected by the classification signal DKA may be an arithmetic expression including the above-mentioned basic exposure amount, like the above-mentioned known arithmetic expression, or may be an exposure amount correction expression for one basic exposure expression. FIG. 5A shows the relationship between the classification based on the density key information DK input by visual judgment and the selection of the set calculation formula. 14, and the classification signal DKA (DKA1~
DKA4) and outputs this classification signal DKA1~DKA4
The calculation formulas a to d set in the exposure calculation formula determining section 14 are selected respectively. Therefore, when the density key information DK determined visually for the negative film 1 is "-1", the classification signal DKA1 is output from the control method selection section 11, and formula a is used to calculate the exposure amount. The characteristic value CV obtained by scanning by the photometer 8 is substituted into the equation, and the negative film 1 is printed with the obtained exposure amount. Density key information DK by visual judgment is
When "-2", it can be used to reduce the constant exposure amount from the calculation result of equation a. FIG. 5B is an example showing the key input relationship between normal correction and classification correction using the conventional density correction key. Normal key correction is “-1” key or less (correction amount ≦-30
%), the classification signal DKA1 is output when any key below the "-1" key is pressed for classification correction, and the appropriate exposure correction amount or exposure amount is determined by equation a. is determined. “-2” key to “+2” key (-
50%<correction amount≦+50%), negative films that require proper key input will be classified as “0” for correction.
All you have to do is press the key, the classification signal DKA2 is output, the arithmetic expression b is selected, and an appropriate exposure correction amount or exposure amount is determined. In this case, in the conventional normal correction, it was necessary to select one of the five correction keys, but in the classification correction, this is not necessary. Other key inputs for classification correction are similarly shown in FIG. 5B. Figure 5C shows the classification signal DKA1~ in classification correction.
This shows DKA4 and how the exposure changes due to it. When the classification signals DKA1 to DKA4 are input from the density correction keys, the characteristics of the classification correction are clear when compared with the normal correction shown in FIG. That is, in normal correction, one exposure change amount is determined for one density key information, but in classification correction, the exposure change amount changes for one density key information depending on the characteristics of the negative film to be printed. , an appropriate amount of exposure change is determined for each negative film. Note that the difference in slope between the dashed-dotted line DOL in Figure 5C and the solid line for each classification correction means that
This suggests that the exposure calculation formula does not properly determine the exposure amount for all negative films in accordance with the characteristics of the negative film. Therefore, by appropriately selecting and using a plurality of exposure calculation formulas, it becomes possible to obtain an unprecedentedly high pass rate. Next, an example of the pass rate when the above method is actually used is as follows.

[Table] Here, the pass rate of expert judgment is 91.4%
, it can be seen that this method provides a higher pass rate and higher quality than the conventional visual judgment of all items. If each negative film is visually judged accurately as shown in FIG. 5B, it is possible to obtain an even higher pass rate. Furthermore, since the determination work is simple, work efficiency can be increased and individual differences can be reduced. In the evaluation of this invention, the exposure change rate was 60%.
If it were possible to classify by interval, it should be possible to obtain a 100% pass rate (with the optimum value ±30% as the pass range) without any calculations, but even an expert can only judge with the accuracy described above. Classification with a narrow rate of change (eg, 60% interval) is difficult to increase the pass rate because it includes classification errors, and has the disadvantage of decreasing the pass rate for non-experts. Therefore, 60%
Scenes corresponding to exposure compensation areas that cover the change rate above (preferably 100% or more) are classified into the same category, and then the appropriate corrected exposure amount for LATD is calculated using a calculation formula, or the final exposure amount is directly calculated using a calculation formula. You can just ask for it. In addition, although the above explanation was based on the corrected exposure amount for ease of explanation, the above subject group (i) is a scene where the exposure amount is reduced, the above subject group (ii) is a scene where no correction is required, and the above The subject group (iii) may be classified as a scene in which the amount of correction is increased, and the subject group (iv) described above may be classified as a scene in which the exposure amount is greatly increased. As mentioned above, the amount of correction is determined, which causes individual differences and difficulty in determination. However, since this invention uses visual judgment only for classification,
A high print pass rate can be obtained without requiring high precision. By using the classification information corresponding to this exposure correction amount, it is possible to collect scenes with similar subject densities, which means that the phenomenon of corrected exposure amount mainly exists on the shadow side, and the automatic judgment section The accuracy of calculation formulas can be dramatically improved. Furthermore, scanning data may be used for classification in addition to visual judgment information, and in that case, the characteristic values include contrast information, screen position density information (for example, screen center density),
Skin information, screen color information, main part or unnecessary part information can be considered, and when contrast information and skin information are used, the processing is as shown in FIG. 6, for example. That is, the above formula a is divided into formula a1 and formula a2 depending on the presence or absence of contrast, and the formula b is divided into formula b1 and formula b2 depending on the presence or absence of skin, and it is determined that formula a is selected in step S1. At the same time, it is determined whether there is contrast (step S4), and if there is contrast, use formula a1, and if there is no contrast, use formula a1.
Make sure to use the a2 formula. Similarly, step S2
After determining that formula b is selected, it is determined whether there is skin (step S3), and if there is skin, formula b1 is used,
If there is no skin, use the b2 formula. Then, in step S5, it is determined whether to select formula c or formula d. By the way, as mentioned above, for the exposure correction amount determined by visual judgment, the density key information DK is used for the exposure amount according to the basic exposure formula. Since this spreads to around ±70%, it is best to prepare exposure calculation formulas with different accuracy of the required classification information and use them according to each person's level of skill. 2000
The experimental data for a negative with frames that passed within the optimum exposure value ±30% are described below.

【table】

【table】

[Table] Level A above is for experts, level B and level C define the judgment criteria for beginners using the corrected exposure amount, and level A is for the definition of input groups and the high Discrimination accuracy is required, and level B is a case where the input group definition and the high discrimination accuracy between groups are reduced. Level C is for beginners, with the accuracy of determining whether correction is required or not required further reduced. Here, the pass rate for experts using the conventional method is 91.4
%, level A can produce prints of higher quality than before, and beginners can achieve performance close to that of experts by using the calculation formula within the correction amount range of level C. come. Furthermore, by making the correction exposure range the same as level A and increasing the number of levels to 10 for experts, the pass rate was 95.2.
reach %. According to actual print evaluation, this value is a pass rate close to 100%, and the effect of this invention is remarkable. In this case, the worker usually performs 10
The 15-level classification can be applied as is, and there are no problems with processing ability deterioration or learning curves. Further, in the above levels A to C, exposure correction amounts are shown for ease of explanation, but in reality, the density correction key input may be performed based on the following criteria. (1) Group for which the exposure compensation amount is decreased: Backlight, snow, low contrast scenes, etc. (2) Group for which the exposure compensation amount is not changed: Normal scenes (3) Group for which the exposure compensation amount is increased: Strobe, background Dark Scenes (4) Groups that greatly increase the amount of exposure correction: Strobe lights, fireworks, etc. in dark places.By simply classifying images according to these criteria, the appropriate exposure amount can be determined. In the conventional normal correction method using the density correction key, it was not possible to determine the exposure correction amount based on such a simple criterion. Conventional characteristic values for calculations do not estimate the main part, so characteristic values are obtained from the entire screen, whereas the visual judgment information allows detailed investigation of the concentration range where the main part exists and selects the characteristic value. As a result, the correlation between the characteristic value and the main part density becomes higher, and it becomes possible to determine the exposure amount better. For example, when it is known that the main part is on the shadow side of the image (negative film for which the amount of exposure compensation needs to be reduced), information on the highlight side is mainly unnecessary, and in the case of a portrait next to a window, the contrast is very large, has a high maximum density, and has a higher density in the center than in the periphery, resembling a characteristic value where the main part is on the highlight side, so a sufficiently appropriate calculation result cannot be obtained. However, by using the coefficients and characteristic values of the calculation formula that takes into account the main density in advance as in this invention, it becomes possible to determine the appropriate exposure amount from the calculation formula, resulting in a high pass rate and high quality prints. becomes possible. Note that in the above case, in the case of classification correction, the classification signal
I select an arithmetic expression in DKA and use the detected characteristic value CV to determine the final exposure amount EX2.
The exposure amount (EX
The exposure correction amount (EX2) for correcting 1) may be determined. In addition, in the above, there are four types of exposure calculation formulas set in advance, a to d, but the number of formulas is arbitrary, and the format of the classification signal DKA for the input density key information DK and the calculation formula for the classification can be selected. can also be changed arbitrarily. Furthermore, the classification signal
Density key information DK from the density correction key 31 is used to generate DKA, but another key is used to input the density key information of the main part of the negative film and the density key information of the background for classification. You can also do it. Note that since the density correction key 31 is used for other purposes such as a color key in addition to the density key, even if it has a different name (for example, numeric keypad), it is simply a difference in name, and of course does not apply to the present invention. It is included. (Effects of the Invention) As described above, according to the photoprinting machine of the present invention,
Correction using the conventional density correction key,
It is convenient for the operator and the like because it is possible to selectively use the density correction key based on the classification of the negative film or the correction using the dedicated key, and there is an advantage that it can be used in accordance with the actual usage situation. In other words, a negative density key is applied to the taxonomic group that decreases the exposure amount.
Density key “0” for taxonomic groups that do not change the exposure amount
By using the plus density key for each taxonomic group that increases the exposure amount, the correction using the conventional density key is common both in terms of operation and in the visual judgment method. can also be used with conventional training. Furthermore, since both types can be used with the same information, the input section can be shared. Further, according to the present invention, the number of negative films to be sorted can be reduced, and even beginners can achieve the same success rate for printing as experts. Furthermore, while the conventional printing limit was 30,000 frames per person per day, this invention has made it possible to print more than 70,000 frames per person per day. Judgment speed has also improved, 30 to 50% faster than before.

[Brief explanation of the drawing]

Fig. 1 is a diagram for explaining the conventional method of determining the printing exposure amount, Fig. 2 is a diagram for explaining the difference in the amount of correction by an expert and an unskilled person, and Fig. 3 is a diagram according to the present invention. A configuration diagram showing an example of a photo printing machine,
Figure 4 is a block diagram showing a part of it in detail, Figure 5
Figures A to C are diagrams for explaining the operating principle of the present invention in comparison with a conventional example, and Figure 6 is a flowchart thereof. 1... Negative film, 2... Mirror box,
3...Light source, 4...Lens system, 5...Shutter,
6... Photographic paper, 7... Filter, 8... Photometering section,
10...Control unit, 11...Control method selection unit, 12
... Conversion section, 13... Exposure amount determining section, 14... Exposure calculation formula determining section, 15... Characteristic value detection section, 20...
...Drive unit, 30...Keyboard, 31...Density correction key, 32...Selection switch.

Claims (1)

[Claims] 1. A photometric section for photometrically measuring a negative film, and an average density, a maximum density,
characteristic value detection means for determining characteristic values such as minimum concentration;
an exposure amount determining means for determining a basic exposure amount based on the average density; an input key means for inputting a judgment result regarding the density by visual judgment of the negative film; and an exposure correction means in accordance with input information from the input key means. a correction amount converting means for calculating the amount; a correction amount determining means for selecting one of the exposure calculation formulas according to the input information and calculating the exposure correction amount by substituting the characteristic value; and the correction amount converting means or a selection means for selecting which of the correction amount determination means to use; and a printing exposure amount determination means for determining a printing exposure amount by applying the exposure correction amount selected by the selection means to the basic exposure amount. and an exposure control section that controls exposure according to the printing exposure amount. 2. The photographic printing machine according to claim 1, wherein the input key means is a density correction key. 3. The photographic printing machine according to claim 1, wherein the input key means is a dedicated key corresponding to the exposure calculation formula. 4. Photographic printing according to claim 1, wherein the input key means comprises a density correction key and a dedicated key corresponding to the exposure calculation formula, and a selection switch selects either one for use. Machine. 5. The photographic printing machine according to claim 1, wherein the visual judgment is an increase/decrease or a degree thereof with respect to the basic exposure amount.