JPS612145A - Controlling method of exposure for printing - Google Patents

Abstract

PURPOSE:To make it possible to print out also a negative film such as a backlighted film having much space, a landscape and a garden in the winter with a proper density and to improve the ratio of successful applicants by applying an optimum exposure control formula to both a picture group and residual negative pictures. CONSTITUTION:The exposure extent of printing is controlled on the basis of an exposure control formula including contrast information and color information in addition to the maximum density information, minimum density information and average density information of the whole and a part of a negative picture. At least six kinds of specific picture groups are extracted and sorted in accordance with the various density information of the measured negative picture and the exposure control formula is calculated on the basis of the sorted result. In the exposure controlling method, printing is executed on the basis of the exposure control formula of which factor Ki is fixed in each sorted pattern. Since DB and IR(W) items are added to the exposure control formula, a negative film such as a backlighted film having much space, a landscape and a garden in the winter can be also printed out with a proper density.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a photographic printing exposure control method for controlling the exposure amount so as to obtain a photographic print having a proper print quality of 8II1 degree in negative-positive type photographic printing.

Conventionally, this type of exposure control method involves quantizing the difference between the average density of the center of the screen and the average density of the whole screen, and the difference between the average density of the upper part of the screen and the average density of the lower part of the screen, and then combining these. It has been proposed that negative films are classified into multiple categories based on logic, and the exposure amount is determined based on a preset exposure correction term for each category, thereby correcting the basic exposure control formula. (Japanese Unexamined Patent Publication No. 51-23936).

That is, the exposure amount is controlled by adding 5RL to 3CF1ka UL+ to a correction term q= in which a coefficient ki is set according to the type of negative film to the exposure amount control basic formula % formula %.

Here, CP=(Dmin+CN/2)-LATL)(W
) CF=DC-DF U'L=DL-DU RL=DRI-DLF kt ``k=,: Constant LATD (W): White full-screen average density [)mi
n: White minimum 81 degrees max: White maximum density DC: Average density at the center of the screen DF: Average density at the right side of the screen DU Average density at the top of the two screens lll1K DL: Average density at the bottom of the screen DRI: Average at the right side of the screen Density DLF: Average density on the right side of the screen (see Figure 1).

The exposure amount control method described above has the effect of improving yields because even negative films containing density defects (subjective density defects) can be finished as photographic prints with appropriate density.

As mentioned above, this method quantizes the difference between the average density of the center of the screen and the average density of the entire screen, and the difference between the average density of the lower part of the screen and the average density of the lower part of the screen, and then converts the combined negative film (scene) into multiple This is to classify the data into categories and select the coefficients of the exposure correction term set in advance according to the classification. The quantized characteristic values in this case are merely mechanically combined, and therefore, once the combination of quantized characteristic values is determined, the classification of the negative is inevitably determined.

The exposure compensation term consists only of combinations of densities at the top/bottom, left/right, and center/periphery of the screen, so it is useful for negative film taken in backlit situations with a lot of sky, landscapes, winter gardens, etc. may not be able to achieve the proper density. For example, since the correction term q has kaUL, correction is made for backlight, but the sky area is 3. If the deviation is greater than /4, the UL value becomes small, making it impossible to perform effective correction. In addition, since the basic exposure control formula does not include a characteristic value that represents the average contrast of the entire screen, the density will be too high for landscapes, and for objects that are exposed to sunlight such as a garden in winter. If there are both shaded areas and shaded areas, the density will be too low and it will not be possible to obtain good photographic prints.

The present invention solves the above-mentioned drawbacks, and is a photographic printing exposure control method that allows negative films such as those shot under backlight with a large amount of sky, landscapes, winter gardens, etc. to be finished at an appropriate 1llffl. The purpose is to provide the following.

The printing exposure control method of the present invention does not classify negatives by simply combining characteristic values obtained by measuring negatives and quantizing or digitalizing them, as in conventional methods. From the obtained values, special image groups such as negatives with low contrast images, negatives with high contrast images, underexposed negatives, overexposed negatives, and negatives with partial sky in the periphery are extracted, and this image group is The optimum exposure control equation is applied to the image, and the exposure control equation suitable for the remaining image negatives is also applied. The present invention controls the exposure amount during printing using an exposure amount control formula that includes contrast information and color information in addition to maximum density information, minimum density information, and average density information for the entire negative screen and portions. Then, the above-mentioned special image groups are extracted and classified based on various density information of the measured negative, and a separate exposure amount control formula is calculated according to the classification results.

That is, the exposure amount control method of the present invention is characterized in that printing is performed based on an exposure amount control formula % formula % in which a coefficient Ki is determined for each classified pattern.

In the above equation (1), this is the average value of the difference between adjacent measurement points and represents the average contrast of the entire screen.

Moreover, IR(W) is the number of white objects. Actually, if the blue density is B, the green density is 01, and the red density is R, then G-B,
In two-dimensional coordinates with RG as an axis, what is included in a circle with a radius of 0.1 centered on the coordinate origin is defined as white.

Therefore, something like a white cloud falls under this category.

Since the above formula (1) includes 7 DB1 and 81 R(W), if the photograph was taken under backlight with a lot of sky, ffi
Even landscapes and winter gardens can be printed with appropriate density. For example, if there is a lot of sky, the characteristic value Ka
Since the value of IR(W) (Ke <O) becomes large, negative correction is performed and the human face does not appear dark.

Furthermore, in the case of landscapes, what about characteristic values? DB (K7 >'
Since the value of O) becomes small, it is corrected negatively, and because things like the garden in winter become large, it is corrected positively. The result is a photographic print with appropriate density.

The present invention will be explained in detail below.

FIG. 2 is a flowchart outlining the present invention. First, the full screen density characteristic value LATD (W)D of negative film
max, Dmin, DB, IR (W), partial screen density characteristic value DL, DU, ORL DLF, DC, DF, FM
Measure AX and CMAX. Here, CMAX is the maximum density at the center of the screen, and FMAX is the maximum density at the periphery of the screen. Using these characteristic values, each negative film is classified into the following patterns.

a) Low contrast b) Underthings C) Over d) High contrast e) Includes some sky in the periphery f) Items not included in a) to e) above The above a) to f) are preferably in the following ranges.

a) Low contrast CN≦1.0 and CP-0, 2LATD(W)<+0.
05 b) Under □max≦1.1 or LATD (W>≦0.4 C) Over Dmin≧0.6 or more, ATD (W>≧1.0 d) High contrast CN≧ 1.2 e) Items that include some sky in the peripheral area FCMAX≧0.2, CP≧0.1 and CF<0.1 f) Items that are not included in a) to e) above (average with proper exposure) The characteristic value CN used for the above classification is the maximum white density Om
ax (W) and white minimum 81 degrees 1) min (W
) is the difference. Further, FCMAX is FMAX-CMAX.

After these classifications, the exposure amount is controlled by an equation in which l(i is defined for each classification based on experience in the exposure amount control formula % formula %).

i.e. a) low contra, strike one X1=at +az DmaX+a3[)m! n-
am 1-ATD (W) 10a, D, B-a61 R
(W) −(2) b) Under X2 =bt +b2D'maX+b30m i nb
h LATD (W) b5cF+b 6UL+br DB...(3) C) Over X3 =-Ca +C2Dmax+c3Dmin
Ca 1-ATD (W>+C3CF+C8LJL+0
7 DB 08 IR(W)...(
4) d) High contrast one Xi -dt +dz Dmax + d3[)min
da LATD (W)+d5OF+ds UL+d
y DB d8IR(W>...(5
〉 e) Part of the sky is included in the periphery X6 = el + e2 Dmi rl-e3
LATD(W)-[, CF-1-es uL +ee
DB... (6)f
)Things other than a) to e) above
fa'LATD(W)+fsCF+feLIL+f
yDB (7) Calculate by substituting each characteristic value according to the exposure amount control formulas (2) to (7) determined for each classification. The exposure time may be controlled based on this calculated value.

For classification a), aylR(G)+a is added to formula (2).
81R(R) may be added. TR(G) is the number of green colors, and IR(R) is the number of red colors. IR(G
) is effective for negative films containing grass, and IR (R) is effective for negative films containing autumn leaves, and positive correction is performed by these terms, resulting in a higher density.

After or before the classification, those whose left-right density difference or vertical density difference is equal to or greater than a certain value are extracted. Based on this difference in density between the left and right sides, it is possible to determine whether the sky is visible on the left or right side of the photograph, since the photograph was taken with the camera held in a vertical position. In this case, since the vertical and horizontal directions are reversed, it is necessary to replace UL with RLA in each of the exposure control formulas 2) to 7). here RL
A is the absolute value of RL, i.e. IDPI-DLFI.

Also, most of the images with a large difference in density between the top and bottom are those taken under backlight, snow in the lower part of the screen, and concrete in the lower part of the screen. Furthermore, although most cameras take pictures from left to right, only about 5% of the pictures are taken by cameras that take pictures from right to left, and the signs of these ULs are reversed. Negative correction (reducing the angle by 11 degrees) is effective in the case of backlight and snow, and positive correction is effective in the case of concrete. Therefore U[
Depending on the scene, replace ULA or zero.

Here, ULA is IULI. For the same reason, UL→±RLA or zero is also replaced for the case where there is a difference in left and right density. -q) Those with left and right density differences RLA≧1.5 h) Those with top and bottom density differences ULA≧1.5 Those with left and right density differences are replaced using the following discriminant.

XX=0.3+0.8LAT'D (W)+1.5CF
-0,5UL-1,IDLF-0゜00081R(W)
...(8) If ××≧0.09, UL-→RLA If XX≦-0,09, UL-→-RLAO, o9<x
If x<-o, 09, tJL→zero.

For those with a difference in upper and lower density, UL→± is determined using the same discriminant formula.
Replace ULA or zero.

According to the present invention having the above configuration, the DB
and IR (W>), it is possible to print negative films with appropriate density even for backlit scenes with a lot of sky, landscapes, and winter gardens.Also, for 2175 pudding 1~photographs. On the other hand, visual judgment was performed to pass the range of ±20% around the target concentration.
While the pass rate for No. 936 was 81.0%, the pass rate for the present invention was 89.0%, which was quite good.

[Brief explanation of drawings]

Figure 1 is a plan view of a negative film showing how the screen is divided;
FIG. 2 is a flow chart of the present invention.

Claims (10)

[Claims] (1) Based on characteristic values obtained by scanning the film screen, such as full-screen density characteristic values, partial screen density characteristic values, or a combination thereof, negative film images are at least a) low-contrast; b) Under-cover c) Over-cover d) High-contrast e) Parts with some sky in the periphery f) Items not included in a) to e) above are classified into six types, and the coefficients are determined in advance according to this classification. Ki
Exposure control formula X=K_1+K_2Dmax+K_3Dmin+K_4
LATD(W)+K_5CF+K_6UL+K_7DB
+K_8IR(W) is calculated, and the printing exposure is controlled based on the calculation result. (2) During the above classification, those with low contrast are classified as CN≦1.
0 and within the range of CP-0.2LATD(W)<0.05.
Photographic printing exposure control method described in Section 1. (Here, CN is the difference between the highest and lowest white density, and CP is (Dmin+CN/
2)-LATD(W), Dmin is the minimum density of white, L
ATD (W) is the average density of white over the whole screen) (3) Among the classifications, the under category is defined in the range of Dmax≦1.1.
3. The photographic printing exposure amount control method according to item 1 or 2. (4) Among the classifications, the under category is defined in the range of LATD(W)≦0.4.
3. The photographic printing exposure amount control method according to item 1 or 2. (5) Claim 1 characterized in that, in the above classification, over-sized ones are defined in the range of Dmin≧0.6.
The photographic printing exposure amount control method according to any one of paragraphs 1 to 4. (6) Claim 1 characterized in that, in the above classification, over-sized ones are defined in the range of LATD(W)≧1.0.
The photographic printing exposure amount control method according to any one of paragraphs 1 to 4. (7) During the classification, those with high contrast are classified as CN≧1.
Claim 1 characterized in that it is defined in the scope of 2.
6. The photographic printing exposure amount control method according to any one of paragraphs 6 to 6. (8) Among the above classifications, those that include some sky in the peripheral area are FCM
The photographic printing exposure amount according to any one of claims 1 to 7, characterized in that AX≧0.2, CP≧0.1, and CF<0.1. Control method. (Here, FCMAX is the difference between the maximum density FMAX at the periphery of the screen and the maximum density CMAX at the center of the screen, FMAX - CMAX
(X, and CF is the difference between the average density DC at the center of the screen and the average density DF at the periphery of the screen, DC - DF) (9) Among the negative films mentioned above, if there is a difference in left and right density such that the characteristic value RLA≧1.5, the UL during exposure control should be adjusted to ±
Any one of claims 1 to 8, characterized in that the calculation is performed in place of RLA or zero.
Photographic printing exposure control method described in Section 1. (Here, RLA is the absolute value of the density difference between the left and right sides of the screen |DRI-DLF|. DRI is the average density on the right side of the screen, DLF is the average density on the left side of the screen. UL is the density difference between the top and bottom of the screen (DL -DU). DL is the average density in the lower part of the screen, DU is the average density in the upper part of the screen) (10) Characteristic value ULA≧1.5 of the negative film
Any one of claims 1 to 8 is characterized in that when there is a difference in upper and lower density, UL in the exposure control equation is replaced with ±ULA or zero. The photographic printing exposure control method described.