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(11) | EP 1 083 460 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Method and apparatus for exposing a photosensitive material |
| (57) The invention relates to a method and apparatus for exposing a photosensitive material
such as colour negative film, colour reversal film and colour photographic paper,
for evaluating the photographic characteristics of said photosensitive material. At
least two different areas of the material are exposed differently and at least one
light beam is used. At least one light beam is split into at least first and second
parts which are equal to each other. At least two different areas are respectively
exposed to the first part of the said light beam and the second part of the said light
beam. |
[0001] This invention relates to a method for exposing a photosensitive material, such as colour negative film, colour reversal film or colour photographic paper, for evaluating the photographic characteristics of said photosensitive material, in which at least two different areas of the material are exposed differently, and at least one light beam is used.
[0002] This invention also relates to an apparatus for exposing a photosensitive material, such as colour negative film, colour reversal film or colour photographic paper, for evaluating the photographic characteristics of said photosensitive material, in which at least two different areas of the material are exposed differently, and at least one light beam is used.
[0003] In the case of colour photographic materials, for example colour negative film and colour paper, the material is usually composed of a red sensitive layer, a green sensitive layer, and a blue sensitive layer. After the exposure and photographic development, the sample is measured with a densitometer in order to evaluate the performance of the photographic material.
[0004] In the evaluation of colour photographic materials the exposure is performed with red, green, blue or composed light. The composed light means light which has its intensity in the spectrum of which the wavelength varies between 320 - 800 nm, such that the composed light includes blue, green, and red light. In the case of red light exposure, substantially only the silver halide crystals of the red sensitive layer can be changed physically. The light absorbed by the red sensitive layer generates a so-called latent image in the silver halide crystals (This means a kind of physical change in a crystal.) of the red sensitive layer, which can be developed in the developing process later. In the case of green light exposure, substantially the silver halide crystals of the green sensitive layer can be changed physically. The light absorbed by the green sensitive layer generates a latent image in the silver halide crystals of the green sensitive layer. In the case of blue light exposure, substantially the silver halide crystals of the blue sensitive layer can be changed physically. The light absorbed by the blue sensitive layer generates a latent image in the silver halide crystals of the blue sensitive layer. In the case of composed light exposure, the silver halide crystals in the red, green, and blue sensitive layers can be changed physically. The light absorbed by these sensitive layers generates the latent images in the silver halide crystals of these sensitive layers.
[0005] After the exposure, the photographic material is developed photographically. Cyan colour dye formation occurs in the red sensitive layer by the reaction of cyan dye forming coupler with an oxidized aromatic primary amine which is produced from colour developing agent by the development reaction with the silver halide crystals in the red sensitive layer that have the latent image. Magenta colour dye formation occurs in the green sensitive layer by the reaction of magenta dye forming coupler with an oxidized aromatic primary amine which is produced from colour developing agent by the development reaction with the silver halide crystals in the green sensitive layer which have the latent image. Yellow colour dye formation occurs in the blue sensitive layer by the reaction of yellow dye forming coupler with an oxidized aromatic primary amine which is produced from colour developing agent by the development reaction with the silver halide crystals in the blue sensitive layer that have the latent image. After the bleach, fix, and stabilization processes, and so on, a colour image is established.
[0006] By changing the light intensities, the colour densities (cyan, magenta, and yellow densities) will vary and can be measured with the densitometer. By doing so, the sensitometric result (sensitivity, gradation, and so on) of the photographic material can be obtained.
[0007] In the case of composed light exposure, the red-, the green-, and the blue-sensitive layers can be changed physically and can be developed simultaneously. In that case, an interaction between these layers may occur. This interaction will be explained in more detail. For example, during the development of the red sensitive layer, some development inhibitor can be released from the red sensitive layer and diffuses into other layers, like the green sensitive layer, after which it suppresses the development of the green layer. This inhibitor is sometimes a halogen ion that is released during the development of the silver halide crystal. In some cases, a particularly designed inhibitor is included intentionally. This means that the amount of magenta dye produced in the green sensitive layer becomes less compared to that without the development in the red sensitive layer. This is an example of an interaction between the red and green sensitive layers, and hence several interactions are possible with three sensitive layers. It is important to evaluate these interaction effects in order to design a photographic material. This can be done by comparing the sensitometric results of separate exposures (red, green and blue lights) and the composed exposure (combined exposure of red, green and blue lights).
[0008] In the known exposure machine, the separate exposures are possible by using appropriate colour filters and an optical wedge. As colour filters, blue, green and red filters or diffraction grating filters etc. can be used. An optical wedge is a neutral density filter with a density gradation. A continuous wedge or a step wedge may be used. An example of a continuous wedge is shown in Fig.1c and 1d.
[0009] For the composed light exposure it is known to use a grey fil-ter (neutral density filter. This has a uniform absorption over the whole visible spectrum for a wavelength range between 400 - 700 nm.) and an optical wedge. Further it is known to expose the photographic material to blue, green, red and composed light, by means of four appropriate filters, respectively.
[0010] The problem with the known methods and apparatus is that one can not reveal with a satisfactory level of reliability the interaction between the red, green and blue sensitive layers. As explained above, the interactions between these layers are determined by comparing the sensitometric results which are obtained by the separate exposures to red, green and blue light on the one hand and to composed light on the other hand.
[0011] The invention is based on the insight that the composed light exposure with the known method and apparatus is not merely the sum of the separate red, green and blue light exposures. The composed light exposure has a different spectrum (including wavelength and intensity) from the sum of the separate red, green and blue light exposures. This means that the spectrum and total energy of light which is received by the blue sensitive layer in the case of a composed light exposure is different from the spectrum of light which is received by the blue sensitive layer in the case of a separate blue light exposure. Similarly, the spectrum of light which is received by the green sensitive layer in the case of a composed light exposure is different from the spectrum of light which is received by the green sensitive layer in the case of a separate green light exposure . Finally, the spectrum of light which is received by the red sensitive layer in the case of a composed light exposure is different from the spectrum of light which is received by the red sensitive layer in the case of a separate red light exposure. It follows that if the sensitometric result of each sensitive layer in the area which receives composed light differs from the sensitometric result of each sensitive layer in the area which receives separately blue, green and red light, respectively, this difference can be caused by the spectrum difference mentioned above and the interaction between the sensitive layers. For example, the sensitometric result of the blue sensitive layer (which can be measured by the yellow density) in the area which receives composed light will differ from the sensitometric result of the blue sensitive layer in the area which receives separately blue light. The sensitometric result of the green sensitive layer (which can be measured by the magenta density) in the area which receives composed light will differ from the area which receives separately green light. The sensitometric result of the red sensitive layer (which can be measured by the cyan density) in the area which receives composed light will differ from the area which receives separately red light. These differences are caused by the spectrum difference and the interaction between the sensitive layers.
[0012] In order to accurately evaluate the interaction between the sensitive layers using the sensitometric results after development for the combined composed light exposure and the three separate light exposures, it is necessary, in accordance with the invention, to expose the composed area to the exact sum of the separate exposures applied to the red, green, and blue areas, respectively.
[0013] Therefore, in accordance with the invention, the method for exposing a photosensitive material, for evaluating the photographic characteristics of said photosensitive material, in which at least two different areas of the material are exposed differently and at least one light beam is used, characterized in that the at least one light beam is split into at least a first and a second part which are equal to each other, while the at least two different areas are at least exposed to the first part of the at least one light beam and the second part of the at least one light beam respectively. This type of method can be used advantageously for this evaluation.
[0014] In this method, for example, the at least one light beam may be red light. In order to evaluate the green and red layers of the photographic material, including their possible interaction, the red light beam is splitted into a first and a second part which are equal to each other and the first part of this red light is projected on one area of the photographic material. The sum of the second part of the red light and another light beam (green light in this case) is projected on the other area of the photographic material. The interaction between the two layers can be determined by comparing the sensitometric result of the cyan dye in the area which is exposed to red light and the sensitometric result of the cyan dye in the area which is exposed to the sum of red and green light.
[0015] The method may in accordance with the invention further be characterized in that at least two light beams having different spectra are each split into at least a first and second part which are equal to each other, while a first area of the at least two different areas is exposed to the first part of the first light beam, a second area of the at least two different areas is exposed to the first part of the second light beam, and a third area of the at least two different areas is exposed to the sum of at least the second part of the first light beam and the second part of the second light beam. In this method, the first light beam is, for example, a red light beam, while the second light beam is a green light beam. In that case the green and red layers of the photographic material are tested, including their mutual interaction. The interaction between these layers can be determined by comparing the areas which have received red light, green light and the sum of red and green light, respectively.
[0016] Preferably, the method according to the invention is further characterized in that further a third light beam having a different spectrum than the first and the second light beam is split into at least a first and second part which are equal to each other, while a fourth area of the at least two different areas is exposed to the first part of the third light beam, and the third area is exposed to the sum of at least the second parts of the first, second and third light beam. The first, second and third light beam may for example be a red, green and blue light beam respectively. In that case the areas which are exposed separately to red, green and blue light are compared with the area exposed to the sum of these lights, as a result the interaction between the sensitive layers can be determined.
[0017] The apparatus according to the invention, is characterized in that the at least one light beam is split into at least first and second parts which are equal to each other, while the at least two different areas are exposed to the first part of the said light beam and the second part of the said light beam respectively. This type of apparatus can be used advantageously for the above referred evaluation.
[0018] The apparatus may according to a preferred embodiment of the invention further be characterized in that at least two light beams having different spectra are each split into at least a first and a second part which are equal to each other, while a first area of the at least two different areas is exposed to the first part of the first light beam, a second area of the at least two different areas is exposed to the first part of the second light beam, and a third area of the at least two different areas is exposed to the sum of at least the second part of the first light beam and the second part of the second light beam.
[0019] The invention will presently be further explained with reference to the drawings, wherein
Fig. 1a is a side view of a part of an exposure apparatus known per se;
Fig. 1b is a top plan view of the colour filter of the apparatus according to Fig. 1a;
Fig. 1c is a top plan view of an optical wedge of the apparatus according to Fig. 1a;
Fig. 1d shows a characteristic depending on the geometric position of an optical wedge of the apparatus according to Fig. 1a;
Fig. 2 is a top plan view of a developed test material exposed with the apparatus according to Fig. 1a;
Fig. 3a shows schematically the relation between the density of a blue exposed area of the test material according to Fig. 2 and the amount of light to which this area has been exposed;
Fig. 3b shows schematically the relation between the density of a green exposed area of the test material according to Fig. 2 and the amount of light to which this area has been exposed;
Fig. 3c shows schematically the relation between the density of a red exposed area of the test material according to Fig. 2 and the amount of light to which this area has been exposed;
Fig. 3d shows schematically the relation between the density of a composed exposed area of the test material according to Fig. 2 and the amount of light to which this area has been exposed;
Fig 4a schematically shows a first part of the apparatus according to the invention for carrying out a method according to the invention;
Fig. 4b shows the light distribution box of the apparatus according to the invention;
Fig. 4c shows a cross section at the entry of the apparatus according to Fig. 4b;
Fig. 4d is a top plan view of the apparatus according to Fig. 4b;
Fig. 5 is a top plan view of a developed test material exposed with the apparatus according to Fig. 4
Fig. 6a shows schematically the relation between the density of a blue exposed area of the test material according to Fig. 5 and the amount of light to which this area has been exposed;
Fig. 6b shows schematically the relation between the density of a green exposed area of the test material according to Fig. 5 and the amount of light to which this area has been exposed;
Fig. 6c shows schematically the relation between the density of a red exposed area of the test material according to Fig. 5 and the amount of light to which this area has been exposed;
Fig. 6d shows schematically the relation between the density of a composed exposed area of the test material according to Fig. 5 and the amount of light to which this area has been exposed;
[0020] In Fig. 1, reference numeral 1 designates a part of an apparatus, known per se, for exposing a photosensitive test material, for instance, a colour negative film, a colour reversal film, or a colour photographic paper, etc. The apparatus 1 comprises a light source 10, a colour filter 2 and an optical wedge 4 arranged on top thereof. As can be seen in Fig. 1b, the colour filter comprises a red area 6a, a green area 6b, a blue area 6c and a grey or clear area 6d. The optical wedge has a density going from high to low, from left to right in the drawing. This means that the light intensity which is passed by the optical wedge 4 increases from left to right in the drawing (see also Fig. 1d). In use, a test sample 8 is placed on top of the optical wedge 4. Then a homogeneous composed light 10 is supplied at the bottom of the colour filter 2. After the test sample 8 is developed, the test sample 8 will contain four different areas, which are exposed to four different light spectra (Fig. 2). The first area 10a has been exposed to the red light, with increasing intensity from left to right as viewed in the drawing. In the area 10a, substantially only the layer sensitive to red light will undergo a physical effect. This layer is developed, so that a cyan dye is formed. Similarly, the area 10b will be exposed to green light. This means that in the area 10b substantially only the layer sensitive to green light will be exposed and after development a magenta dye will be formed in this area. The area 10c is exposed to blue light. This means that substantially only the layer sensitive to blue light will undergo a physical effect. Then, after development, a yellow dye is formed.
[0021] Finally, the area 10d is exposed to composed light. Because composed light comprises both red, green and blue light, this means that in this area the layers sensitive to red light, to green light and to blue light, respectively, will undergo a physical change. As a result, in the grey area, a cyan dye, a magenta dye and a yellow dye are formed.
[0022] Fig. 3a shows schematically the relation between the density of blue exposed area 10c of the test material according to Fig. 2 and the amount of light to which this area has been exposed. The density is plotted along the vertical axis and the logarithm of the intensity of the received light is plotted along the horizontal axis. At this exposure, only the yellow dye is formed substantially. The formed dye amount is dependent on the amount of light. The magenta and cyan dye will hardly be formed here.
[0023] Fig. 3b shows schematically the relation between the density of the green exposed area 10b of the test material according to Fig. 2 and the amount of light to which this area has been exposed. At this exposure, only the magenta dye is formed substantially. The formed dye amount is dependent on the amount of light. The yellow and cyan dye will hardly be formed here.
[0024] Fig. 3c shows schematically the relation between the density of the red exposed area 10a of the test material according to Fig. 2 and the amount of light to which this area has been exposed. At this exposure, only the cyan dye is formed substantially. The formed dye amount is dependent on the amount of light. The yellow and magenta dye will hardly be formed here.
[0025] Fig. 3d shows schematically the relation between the density of the composed exposed area 10d of the test material according to Fig. 2 and the amount of light to which this area has been exposed. At this exposure, yellow, magenta, and cyan dyes are formed. The formed dye amounts are dependent on the amount of light.
[0026] For example, the sensitometric characteristics of the blue sensitive layer in the area exposed to the separate blue light (which is shown by the yellow density curve in Fig 3a) is different from that in the area exposed to the composed light (which is shown by the yellow density curve in Fig. 3d), because of the interaction between the sensitive layers and the difference of spectrum absorbed in the blue sensitive layers. Similar explanation can be given to the magenta and cyan density curves, which are shown in Fig 3b and 3c . The insight into the cause of this problem constitutes the basis of the present invention, which will be further explained.
[0027] Therefore, it is not possible to state that, for instance, the cyan dye formed in the area 10d corresponds to the cyan dye formed in the area 10a even if there were no interactions with other dyes. Similarly, it is not possible to state that the magenta dye in the area 10d corresponds to the magenta dye formed in the area 10b even if there were no interactions with other dyes. Finally, it is not possible to state that the yellow dye formed in the area 10d corresponds to the yellow dye formed in the area 10c even if there were no interactions with other dyes. Because the formed dye amounts are not equal even in the absence of interaction, differences between these dyes cannot be attributed merely and solely to interactions between the layers sensitive to different colours in the area 10d. In Fig. 3d it is indicated with primes that the cyan' dye, magenta' dye and yellow' dye formed are not equal to the cyan dye, magenta dye and yellow dye formed according to Figs. 3a to 3c.
[0028] The method and apparatus according to the invention which solves above mentioned problem will be further described with the reference to Figs. 4a to 4e.
The apparatus 12 comprises a light source 14, which generates composed light. The apparatus further comprises a red filter 16, to which a portion of the composed light is applied for obtaining a first light beam 18, which consists of red light. Further, the apparatus comprises a green filter 20, to which the same amount of composed light from the light source 14 is applied as to the red filter 16. Thus, a second light beam 22 is formed, which consists of green light. Entirely analogously, the apparatus further comprises a blue filter 24 for obtaining a third light beam 26, which consists of blue light. The red light 18 is supplied to a beam splitter unit 28, known per se, for splitting the first beam 18 into at least a first part 30 and a second part 32 which are equal to each other. In a preferable example, a beam splitter 28 is composed of bundles of optical glass fibers. In the entrance part of 28, it is a bundle of several hundred of fibers and in the middle part, this bundle is exactly divided into two identical parts. The light introduced in the entrance of 28 is exactly divided into two equal parts.
[0029] The apparatus further comprises a second beam splitter unit 34, for splitting the second light beam 22 into at least a first and second part 36, 38 respectively which are equal to each other. The apparatus further comprises a third beam splitter unit 40, for splitting the third light beam 26 into at least a first part 42 and a second part 44 which are equal to each other.
[0030] As can be seen in Fig. 4a, the apparatus further comprises a first beam combination unit 46, known per se. It is composed of components 48, 50, and 52. It has two functions in this example, beam combination and beam splitting. First it sums the second parts 32, 38, 44 of the first, second and third beam 18, 22, 26. The sum of these parts is formed in component 48 of the first beam combination unit 46. Second, the so determined sum of three light beams is split into two equal parts also in component 48, which are available at the outputs 50 and 52, respectively, of the beam combination unit 46. In a preferable example, a beam combination unit 46 is composed of bundles of optical glass fibers. The bundle from three parts (which introduces blue, green, and red light) are collected and randomized and then divided into two identical parts in 48. Thus, the light from 32, 38, and 44 are summed and divided into exactly two identical parts. The reason why the bundle is divided into two parts is to make the light uniform in the light distribution box explained later.
[0031] In this example, the first part 30 of the first beam 18 is applied to a second beam combination unit 54, which is identical to the first beam combination unit 46. Because only the first part 30 of the first light beam 18 is applied to the beam combination unit 54, half of the first part of the first beam 18 will be available at the output 50' of this beam combination unit 54, while the other half of the first part 30 of the first light beam 18 is available at the output 52'. Entirely analogously, the first part 36 of the second light beam 22 is applied to a third beam combination unit 56, while the first part 42 of the third light beam 26 is applied to a fourth beam combination unit 58.
[0032] The lights generated at the outputs 50 and 52 of the first beam combination unit 46 is applied to light distribution means, which are schematically shown in Fig. 4b. Fig. 4c shows a cross section at the entry of this apparatus. The light distribution means in this example consist of a light distribution box 60. The light available at the outputs 50 and 52 of the beam combination unit 46 is merged again in one compartment of the light distribution box 60 in a manner known per se, such that the light in question egresses uniformly at the top 62 of the light box. In order to make the light uniform, it is also preferable that this distribution box has adjustable masks and opal glass as shown in Fig. 4b. At the top 62 of the light box, further, an optical wedge 64 is arranged, which corresponds in properties to the above-discussed optical wedge 4 . Placed on top of the optical wedge is the test sample 8. Further, the light of the second beam combination unit 54, available at the outputs 50' and 52', are supplied to another compartment of the same light box 60. Entirely analogously, this also holds for the light egressing from the third and fourth beam combination units 56, 58. Accordingly, the light associated with the outputs 50'' and 52'' are also combined in another compartment of the light distribution box 60, such that they egress uniformly at the top 62 and are applied to the optical wedge 64. Entirely analogously, the same holds for the light beams egressing, respectively, from outputs 50"' and 52"'.
[0033] The test sample 8 which is exposed as shown in Fig. 4d will therefore include the four areas 110a to 110d as shown in figure 5, which area's are similar area's 10a to 10d, as discussed in relation with Fig. 2.
[0034] Because with the aid of the first beam combination unit 46 the second parts of, the first, second and third light beams (red, green and blue) are summed and subsequently are used for exposing the area 110d, it holds presently that, for instance, the layer of this area 110d that is sensitive to blue light is exposed to blue light which corresponds qualitatively and quantitatively to the blue light to which the area 110c is exposed. It also holds that the layer of the area 110d that is sensitive to green light is exposed to green light which corresponds qualitatively and quantitatively to the green light to which the area 110b is exposed. Finally, it holds that the layer of the area 110d that is sensitive to red light is exposed to red light which corresponds qualitatively and quantitatively to the red light to which the area 110a is exposed. In other words, Figs. 6a, 6b and 6c reflect the situation for the areas 110c, 110b and 110a. Fig. 6d reflects the situation for the area 110d. If, presently, differences arise between, for instance, the measured density of yellow in Fig. 6a and the measured density of yellow in Fig. 6d, this can be attributed only to interactions between the sensitive layers in the area 110d that are sensitive to different colours, since here the three layers are each exposed simultaneously, such that the exposure is equal to the sum of the individual exposures according to Figs. 6a to 6c.
[0036] Thus, it is not requisite that in the beam combination units the signals applied to these units and summed in the components 48, 48', 48,'' and 48''' are split into two equal parts to be subsequently merged again in the light distribution box 60. The steps of splitting into two equal parts and subsequent merging have been carried out to apply uniform light beams to the optical wedge 64. However, other methods for obtaining uniform light beams can also be used. It is also possible, however, that the light distribution box 60 is omitted. In that case, the light beams egressing from the units 46, 54, 56, 58 are applied directly to the optical wedge, without being split.
[0037] Also, the beam combination units 54, 56 and 58 can be omitted, for they do not combine light beams. The only reason that they were used is that in this way the first parts 30, 36, 42 of the first, second and third light beams 18, 22, 26 are processed in the same manner as the second parts 32, 38, 44 of these light beams. In other words, what is thus accomplished is that the area 110d is exposed to red, green and blue light of the same quality and quantity as the red, green and blue light to which the areas 110a, 110b and 110c are exposed.
[0038] Also, it will be clear that the apparatus 12 may also be modified such that it can only be used for exposing two layers of the photosensitive material. To that end, for instance, the third light beam 26, the beam splitter 40 and the beam combination unit 58 can be omitted. The area 110d is then exposed to parts of the first and second light beam, while the area 110c is not exposed at all. In this way the interaction can be determined between two layers sensitive to different colours of light. For instance, the first beam 18 can consist of red light, while the second beam 22 consists of green light or blue light. It is also possible that the first beam consists of blue light, while the second beam consists of green light. In this way, the interaction between each set of two layers sensitive to different colours of light can be successively determined. Such variants are all understood to fall within the scope of the invention.
1. A method for exposing a photosensitive material, for evaluating the photographic characteristics
of said photosensitive material, in which at least two different areas of the material
are exposed differently and at least one light beam is used, characterized in that
the at least one light beam is split into at least a first and a second part which
are equal to each other, while the at least two different areas are at least exposed
to the first part of the at least one light beam and the second part of the at least
one light beam respectively.
2. A method according to claim 1, characterized in that at least two light beams having
different spectra are each split into at least a first and second part which are equal
to each other, while a first area of the at least two different areas is exposed to
the first part of the first light beam, a second area of the at least two different
areas is exposed to the first part of the second light beam, and a third area of the
at least two different areas is exposed to the sum of at least the second part of
the first light beam and the second part of the second light beam.
3. A method according to claim 2, characterized in that further a third light beam having
a different spectrum than the first and the second light beam is split into at least
a first and second part which are equal to each other, while a fourth area of the
at least two different areas is exposed to the first part of the third light beam,
and the third area is exposed to the sum of at least the second parts of the first,
second and third light beam.
4. A method according to claim 3, characterized in that the first light beam consists
of red light, the second light beam consists of green light, and the third light beam
consists of blue light.
5. A method according to claim 3 or 4, characterized in that the first, second and third
light beam are generated using a light source.
6. A method according to any one of the preceding claims 3-5, characterized in that the
splitting of the first, second and third light beam, respectively, is carried out
with three beam splitters, which are equivalent to each other.
7. A method according to any one of the preceding claims 3-6, characterized in that the
second parts of the first, second and third beam are applied to a beam combination
unit, for obtaining the sum of the second parts of the first, second and third light
beam.
8. A method according to claim 7, characterized in that via three respective beam combination
units the first parts of the first, second and third light beam respectively are applied
to the material, said beam combination units being functionally equivalent to each
other and to the one applied for obtaining the sum of the second parts of the first,
second and third light beam.
9. A method according to any one of the preceding claims 3-8, characterized in that the
first parts of the first, second and third light beam, as well as the sum of at least
the second parts of the first, second and third light beam are each applied to the
photosensitive material via an optical wedge.
10. A method according to any one of claims 3-9, characterized in that the first parts
of the first, second and third light beam, as well as the sum of at least the second
parts of the first, second and third light beam are each formed into uniform light
beams using a light distribution box.
11. A method according to any one of claims 1-10, characterized in that the photosensitive
material is a colour negative film, or a colour reversal film, or a colour photographic
paper.
12. An apparatus for exposing a photosensitive material, for evaluating the photographic
characteristics of said photosensitive material, in which at least two different areas
of the material are exposed differently, and at least one light beam is used, characterized
in that the at least one light beam is split into at least first and second parts
which are equal to each other, while the at least two different areas are exposed
to the first part of the said light beam and the second part of the said light beam
respectively.
13. An apparatus according to claim 12, characterized in that at least two light beams
having different spectra are each split into at least a first and a second part which
are equal to each other, while a first area of the at least two different areas is
exposed to the first part of the first light beam, a second area of the at least two
different areas is exposed to the first part of the second light beam, and a third
area of the at least two different areas is exposed to the sum of at least the second
part of the first light beam and the second part of the second light beam.
14. An apparatus according to claim 13, characterized in that further a third light beam
having a different spectrum than the first and the second light beam is split into
at least a first and second part which are equal to each other, while a fourth area
of the at least two different areas is exposed to the first part of the third light
beam, and the third area is exposed to the sum of at least the second parts of the
first, second and third light beam.
15. An apparatus according to claim 14, characterized in that the first light beam consists
of red light, the second light beam consists of green light, and the third light beam
consists of blue light.
16. An apparatus according to anyone of claim 14 or 15, characterized in that the first,
second, and third light beams are generated using a light source.
17. An apparatus according to anyone of claim 14 - 16, characterized in that the splitting
of the first, second, and third light beam, respectively, is carried out with three
beam splitters, which beam splitters are equivalent to each other.
18. An apparatus according to anyone of claim 14 - 17, characterized in that the second
parts of the first, second and third beam are applied to a beam combination unit,
for obtaining the sum of the second parts of the first, second and third light beam.
19. An apparatus according to anyone of claim 18, characterized in that via three respective
beam combination units the first parts of the first, second and third light beam respectively
are applied to the material, said beam combination units being functionally equivalent
to each other and to the one applied for obtaining the sum of the second parts of
the first, second and third light beam.
20. An apparatus according to anyone of claim 14 - 19, characterized in that the first
parts of the first, second and third light beam, as well as the sum of at least the
second parts of the first, second and third light beam are each applied to the photosensitive
material via an optical wedge.
21. An apparatus according to anyone of claim 14 - 20, characterized in that the first
parts of the first, second and third light beam, as well as the sum of at least the
second parts of the first, second and third light beam are each formed into uniform
light beams using a light distribution box.
22. An apparatus according to anyone of claim 12 ∼ 21, characterized in that the photosensitive
material is a colour negative film, or a colour reversal film, or a colour photographic
paper.