Radiation imagery chemistry: process – composition – or product th – Color imaging process
Reexamination Certificate
2003-09-30
2004-11-30
Le, Hoa Van (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Color imaging process
C430S401000, C430S933000
Reexamination Certificate
active
06824963
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to processing photographic materials and in particular to films that will be printed digitally i.e. the negative or transparency is scanned to generate a stored digital image which is subsequently printed to generate a hard copy. This printing step might be by ink-jet, electrophotographic or photographic or any other suitable means.
BACKGROUND OF THE INVENTION
Once a film has been exposed it is then processed by being passed through various solutions, such as developer, bleach, fixer and wash solutions, to convert the latent image to a visible image. In certain circumstances it is not viable to have large tanks of processing solutions. In these cases small amounts of processing solutions are used, usually only in a single processing space. Thus solutions which are stable for only a short time can be used. This also leads to more rapid processing. It is known that in order to get rapid processing of multi layer color films, the temperature of the developer can be raised. This increases the rate of development in each layer, but usually the rate is different in each layer. The different rates of development in each layer cause a different contrast in each layer. If this rapidly processed film is printed optically this effect will show in the print and it will be impossible to get good color balance in densities of the image.
To some extent this imbalance of contrast can be overcome by changing the chemical composition of the developer or rebuilding the film. Unfortunately the variable contrast effect is different for every film and therefore there would have to be a different chemical composition of the developer for each film processed. This is impractical. One way around the problem is to digitally scan the film to produce a digital ‘image’. This image can then be adjusted mathematically to balance the contrasts. The contrast correction look-up table can be stored for each film/developer/time/temperature combination.
It is however necessary to identify the process through which the film was processed. This could be done by attaching a suitable marking to the film or film container, notching the film or by ‘writing’ to any associated magnetic coating, such as on the back of an APS film. All of these methods are subject to error, either forgetting to put on the mark or marking with the wrong process identification.
It is known to add chemical indicators to a photographic solution to determine the exhaustion thereof. However these indicators do not remain in the processed product.
The aim of the invention is to mark a photosensitive material, such as a film negative or transparency, that has been processed in a non-standard process, such as rapid processing, and that requires digital scanning and contrast adjustment to print a good hardcopy, in a way that does not require human intervention or human setting up. The invention aims to mark the material inherently.
SUMMARY OF THE INVENTION
According to the present invention there is provided a method of chemically marking photosensitive material that has been processed in a particular way that necessitates digital scanning and contrast adjustment to produce a satisfactory hardcopy.
Preferably an optical brightner is included in the developer solution.
The invention provides a method in which no operator intervention is required to mark material which needs to be digitally scanned and processed to provide a satisfactory hard copy of an image. Thus the method is not subject to human error.
The chemical marker remains in the processed material. Therefore should any re-prints be required at a later date the operator of a mini-lab would be able to determine that scanning and digital optimization is required for satisfactory results.
It is possible that the method of processing could also be used when optical printing should the process affect only the speed or Dmin rather than the contrast. The marking would then alert the person printing the image optically to a different setting required in the enlarger or printer. This could be done automatically if the printer could detect the presence of the marker and react accordingly.
The invention can be used for both film and paper.
DETAILED DESCRIPTION OF THE INVENTION
When an exposed photosensitive material is to be processed it is passed through various solutions to convert the latent image to a visible image. For instance, with a color film the film is passed through a developer solution, a bleach solution, a fixer solution and finally a wash solution. This may be the same for both conventional processing and for non-standard processes such as rapid processing. Alternatively the non standard process may miss some of the steps after the developer is removed, to save time or chemistry, resulting in a scannable but not optically printable image.
According to the present invention one or more chemical compounds are added to one of the processing solutions used to process the material in a non-standard process. This or these compounds are not visible to a scanner or to an optical printer but can be detected by a specific physical method. Preferably the at least one chemical compound is added to the developer solution. However it is not essential to the invention that the compound is added to the developer solution. The chemical compound must remain in the material to some extent after processing.
One example of the method of processing is to put a fluorescent dye in the developer designed to produce a scan only film. The dye could, for example, be an optical brightner. This dye absorbs UV light of a wavelength shorter than that of the visible spectrum and fluoresces in the visible spectrum. The dye is at least partly retained within the film after processing. This could, for example, be within the film's gelatin matrix but equally may be in one of the other layers of the film. When scanning or optical printing the UV light can be filtered out with suitable absorbing filters.
Two experiments using different processing solutions for the processing of film are described below. It will be understood by those skilled in the art that they are examples only and the invention is not limited thereto.
REFERENCES:
patent: 5266986 (1993-11-01), Kobel
patent: 5534395 (1996-07-01), Kamada et al.
patent: 5717972 (1998-02-01), Patton et al.
patent: 5968718 (1999-10-01), Becher
patent: 6153365 (2000-11-01), Goswami et al.
patent: 6605420 (2003-08-01), Nakai et al.
patent: 6632594 (2003-10-01), Nakai et al.
Fyson John R.
Twist Peter J.
Eastman Kodak Company
Le Hoa Van
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