Design of Color Reversal Film with Improved Push-Processing Characteristics

―93― J. Soc. Photogr. Sci. Technol. Japan, Vol.62, No.2, 1999

Technical Report

Design of Color Reversal Film with Improved Push-processing Characteristics

増感処理性に優れたカラーリバーサルフィルムの設計

Sadanobu SHUTO*, Masayuki KURAMITSU * and Shinsuke BANDO*

首藤定伸*・倉光昌之*・坂東信介*

Abstract Push-processing of a color reversal film is widely and generally used in saving a mistake due to underexposure, or in case of shooting when a high speed is required such as sports photography. Because of these, there is an extremely high demand from the market for improvement in push- processing characteristics of a color reversal film. This paper describes the push-processing mechanism of a color reversal film, and introduces the technology to improve push-processing behavior and its application to .an actual product designing.

要旨カラーリバーサルフィルムの増感処理は,露光量不足による撮影ミスを救済したり,スポーツ写真などで高感度を必要とする場合に,広く一般的に行われている。このため,カラーリバーサルフィルムの増感処理性能の向上に対する市場ニーズは極めて高い。本報告では;カラーリバーサルフィルムの増感処理の機構について説明し,増感処理性向上技術と商品設計への応用について紹介する。

Key words: color reversal film, push-processing, solution physical development, colloidal silver, multi- layer structure キーワード:カラーリバーサルフィルム,増感処理;溶解物理現像,コロイド銀,多層構成

times as high a speed (Exposure Index, EI1000) 1. Introduction as that for the standard process (EI100)1),2) Push-processing of a color reversal film is In this paper, we describe push-processing widely and generally used when one wants to mechanism of a color reversal film, and intro- save a mistake due to underexposure, or needs duce the performance of Fujichrome MS100/ high speed, for example, in shooting sports and 1000 and also technology for improving the push- so on. Therefore, we meet the high demand processing characteristics. from the market for improvement in its push- 2. Push-processing of Color Reversal Film processing characteristics. "Fujichrome MS100/1000" , which was put on 2.1 Purpose of Push-Processing sale by Fuji Photo Film Co. in march 1998, is a A color reversal film, which is an original multi-speed film in the pursuit of comprehensive appreciation medium of transmission type, is so improvement of push-processing quality. And designed that its exposure latitude is usually it has an advantage that it can be pushed to ten narrower than that of a color negative film.

Received 20th, January 1999, Accepted 10th, March 1999 平成11年1月20日受付,平成11年3月10日受理 * Ashigara Research Laboratories , Fuji Photo Film Co., Ltd. 210 Minamiashigara, Kanagawa 250-0193 富士写真フイルム(株)足柄研究所〒250-0193神奈川県南足柄市中沼210 ―94― Sadanobu SHUTO et al J. Soc. Photogr. Sci. Technol. Japan

Because of this, in case when one wants to save underexposure due to a mistake, or in case of shooting when a high shutter speed is required,

push-processing is generally used. In some case, push-processing is one of convenient means to create an artistic picture by modifying gradation or color reproduction intentionally. 2.2 Method for Push-Processing Push-processing of a color reversal film is usually done by extending first development (black-and-white development) time in the color reversal processing described below.

First Development (Black-and-White Devel- Fig. 1 Characteristic Curves of Multi-Layer Color Rever- opment) •¨Wash •¨ Reversal •¨ Color Develop- sal Film ment •¨ Adjustment •¨ Bleaching •¨ Fixing •¨ Wash •¨ Stabilizing The standard time of first development is 6 attained by extending the processing time in minutes. Extending this time to 8 and 11 min- contrast with the system where only chemical utes, push-processing of +1 stop and + 2 stops development occurs. are carried out, and by specifying the first devel- B. Each BGR color-sensitive emulsion layer of opment time more minutely, push-processing a multi-layered color film consists of plural which is set up for speed corresponding to every photosensitive layers with different speeds, i.e., 1/3 stop may be carried out. high-speed emulsion layers for shadow gradation 2.3 Mechanism of Push-Processing and low-speed ones for highlight gradation (Fig. In the first developer of the color reversal 1). Because the speed of a color reversal film is processing, silver halide solvents, such as potas- estimated on the basis of the speed at the high- sium thiocyanate and sodium sulfite, are light rather than that at the shadow, it is depen- contained3). Because of this, in the first develop- dent on the speed of the silver halide grains in ment process, silver halide grains are partially the low-speed emulsion layers for highlight gra- dissolved by these silver halide solvents to sup- dation. And since silver halide grains in the ply silver ions in the developer solution in paral- low-speed emulsion layers are usually smaller in lel with chemical development where the devel- size as compared with those in the high-speed oping agent directly reduces the silver halide emulsion layers, they have a tendency of dissolu-

grains to form silver. These silver ions are tion by silver halide solvents in the first devel- reduced to separate out on developed silver oper. Especially in the push-processing where nuclei by the solution physical development the first development is prolonged, dissolution of process. the silver halide grains proceeds more easily. The push-processing of a color reversal film Thus, at the push-processing, the low-speed makes use of this solution physical development emulsion layers contribute less to the speed than phenomenon in the first development, and a at the standard processing, and in place of them, higher speed is achieved by extending the proces- the high-speed emulsion layers play the part of sing time according to the following mechanisms the highlight gradation which then come to of A and B. determine the film speed. As a result, the den- A. In addition to the fact that the solution sity is lowered by push-processing, which yields physical development increases the developed a characteristic curve as if it were one with only silver amount, internal latent images which can- high-speed layer, and one gets an even higher not be developed at the standard development increase in speed in addition to a substantial processing time come to be developed as the first increase in speed as described in A. development time is extended. Thus, in the color reversal processing, much speed increase is Design of Color Reversal Film with Vol.62, No.2, 1999 Improved Push-processing Characteristics ―95―

3. Push-Processing Improving Technologies Intermediate Layers (MFIL) which carry out functions of inter-image effect control and push- As described before, push-processing of a processing characteristics control in addition to color reversal film makes use of the effect of their primary function of color mixing preven- solution physical development during the first tion, are coated between each layer of B (Blue), development. So, it is necessary to introduce G (Green), and R (Red). the technologies for controlling the solution MFIL adjusts each speed of BGR emulsion physical development, when one wants to layers through the speed range from EI100, the improve push-processing characteristics. minimum speed by standard processing, up to For instance, it is known that addition of EI1000, the maximum speed by push-processing. colloidal silver to a emulsion coating enhances Fig. 3 shows the conceptual diagram of func- solution physical development°. One can tions carried out by MFIL. Usually in a color enhance the speed at push-processing by adding reversal film, a yellow filter layer containing a small amount of colloidal silver to an emulsion yellow colloidal silver is coated beneath the layer or to an intermediate layer neighboring the blue-sensitive emulsion layer. This colloidal emulsion layer5)6). Instead of colloidal silver, silver has an effect of promoting solution physi- one can use silver halide fine grains with fog cal development in the neighboring blue nuclei on surface or inside of them so as to photosensitive emulsion layers. During the expand the speed increase by the push- push-processing, development of silver halide processing7"e. On the other hand, one can grains in the blue photosensitive layers are espe- decrease the speed at push-processing by instal- cially enhanced, and the color balance sifts to be ling an intermediate layer between a layer bluish as a result. The MFIL positioned containing colloidal silver or fogged grains and between the blue photosensitive emulsion layer an emulsion layer so as to prevent enhancement and the yellow filter layer has a function of of solution physical development 9). controlling the solution physical development in the blue photosensitive layer and regulates its 4. Application to Product Designing too much speed increase during the push- The following technologies are introduced in processing. On the other hand, the MFIL's "Fujichrome MS100/1000" so as to realize excel - positioned under the green photosensitive layer lent push-processing performance with very lit- and the red photosensitive layer which contain a tle variance in gradation, gradation balance, and small amount of colloidal silver adjust the speeds color balance. It also realizes the image quality of both the green and the red photosensitive and the color reproduction which exceed far layers to meet that of blue photosensitive layer. beyond the level of the conventional high-speed As a result, in push-processing, a blue shift in the color reversal films with the speed, ISO200 or color balance and a distortion in the gradation ISO400. (1) Multi-Functional Intermediate Layer (MFIL) Technology In Fujichrome MS100/1000, Multi-Functional

Fig. 3 Conceptual Diagram of Multi-Functional Interme- Fig. 2 Layer Structure of Fujichrome MS100/1000 diate Layer (MFIL) ―96― Sadanobu SHUTO et al J. Soc. Photogr. Sci. Technol. Japan balance are controlled at the minimum for a film by the push-processing, and by controlling the with MFIL (solid curve in Fig. 3) , as compared solution physical development of the super uni- with one without MFIL (dotted curve in Fig. 3). form fine grains contained in each photosensitive And an excellent push-processing performance is layer, the variation of the gradation and lower- achieved. ing of the maximum density during the push- (2) Accurate Gradation Control (AGC) processing are suppressed, so as to improve the Technology performance of its push-processing characteris- Each BGR color-sensitive emulsion layers of tics further (Fig. 5). Fujichrome MS100/1000 are divided into three (3) Super Uniform Fine Grain (SUFG) photosensitive sub-layers with a different speed. Technology And the super uniform fine grains are suitably Super Uniform Fine Grain technology is mixed and positioned in each of them (Fig. 4). adopted in Fujichrome MS100/1000. It has In MS100/1000, owing to the Accurate Grada- advanced from the Fuji's unique ultra-fine grain tion Control technology comprising multi-layer technology. It has attained the high image qual- structure with super uniform fine grains, not only ity, far exceeding the level of conventional high- the high shadow speed but also excellent linear- speed color reversal films which has equivalent ity have been realized. They both contribute to speeds to those of push-processed MS100/1000. the improvement in its push-processing perfor- Figs. 6 and 7 show the comparisons of the mance. In another words, by setting a high graininess and the sharpness between MS100/ shadow speed, one can get a large speed increase 1000 and "Fujichrome PROVIA400" which has a

Fig. 4 Accurate Gradation Control (AGC) Technology Fig. 6 Comparison of Graininess between MS100/1000 and PROVIA400

Fig. 7 Comparison of Sharpness between MS100/1000 Fig. 5 Characteristic Curves of Fujichrome MS100/1000 and PROVIA400 Design of Color Reversal Film with ―97― Vol.62, No.2, 1999 Improved Push-processing Characteristics

quality and high-saturation. It can be used sole- ly without switching to films with different speeds in shooting situation such as outdoor fashion, sports, and the news, where unpredict- able changes in exposure conditions and great variations in light levels may occur. We hope that this multi-speed color reversal lm with high image quality and high-saturationfi would expand a new world of photographic expression in the field of a high-speed photogra- phing. References

1) S. Shuto, M. Kuramitsu and S. Bando, Summary of Speech for the Annual Meeting of Society of Photo- graphic Science and Technology of Japan 1998, 67 Fig. 8 Comparison of Color Reproduction between (1998). MS100/1000 and PROVIA400 2) S. Shuto, Summary of Speech for Color Lab Seminar 1998, sponsored by Society of Photographic Science and Technology of Japan, 13 (1998). same speed with that of MS100/1000 pushed 3) British Journal of Photography Annual 194 (1988). 4) T. H. James and W. Vanselow, Photogr. Eng., 7, 90 by + 2 stops. From Figs. 6 and 7, it is apparent (1956). that MS100/1000 is superior to PROVIA400 both 5) J. F. Munshi and H. J. Sniadoch, R. C. Tuites, in graininess and sharpness. Eastman Kodak Co., U. S. Patent No. 5,298,369. (4) Improving Color Reproduction Tech- 6) K. Nagaoka, Fuji Photo Film Co., Ltd. U. S. Patent nology No.5,437,968. 7) S. Shuto, Y. Hayashi, M. Fujita and K. Hasebe, Fuji Into MS100/1000, are introduced Fuji's origi- Photo Film Co., Ltd. U. S. Patent No. 4,626,498. nal DIR (Development Inhibitor Releasing) com- 8) S. Shuto and T. Hara, Fuji Photo Film Co. Ltd., JPA pound technology, the advanced Interimage- H7-225,459. Effect Controlling Grain technology and the Fine 9) S. H. Kim and S. A. Pugh, Eastman Kodak Co., U.S. Tuned Spectral Sensitivity technology which Patent No. 5,691,124. 10) S. Ishimaru, H. Ikeda, K. Sakanoue, K. Miyazaki, S. were introduced into "Fujichrome ASTIA Hirano and J. Tamano, Journal of The Society of 100"10)-14). Photographic science and Technology of Japan, 55, Fig. 8 shows comparison of the color reproduc- 174 (1992). tion characteristics between MS100/1000 and 11) S. Shuto, M. Kuramitsu, S. Kuwashima and S. PROVIA400. As shown in Fig. 8, MS100/1000 Bando, FUJIFILM RESEACH & DEVELOP- has realized a high color saturation by the intro- MENT, 43, 1 (1998). 12) S. Shuto, S. Kuwashima, S. Bando and S. Takada, duction of the above technologies to improve IS&T's 50th Annual Conference., Final Program and color reproduction. Proceedings, 210 (1997). 5. Conclusion 13) M. Kuramitsu, H. Ishibashi, S. Shuto and S. Bando, Summary of Speech for the Annual Meeting of "Fujichrome MS100/1000", as a multi-speed Society of Photographic Science and Technology of color reversal film with a new concept, has been Japan 1997, 21 (1997). 14) S. Bando, Summary of Speech for Color Lab Semi- developed in the pursuit of thorough improve- nar 1997, sponsored by Society of Photographic ment of the push-processing characteristics. It Science and Technology of Japan, 16 (1997). is a product which meets the strong demand from photographers who want a high image