Facsimile and static presentation processing – Facsimile – Specific signal processing circuitry
Patent
1997-01-09
1998-12-01
Moore, David K.
Facsimile and static presentation processing
Facsimile
Specific signal processing circuitry
358515, H04N 146
Patent
active
058450564
DESCRIPTION:
BRIEF SUMMARY
This application is a 371 of PCT/DE96/00423, filed Mar. 7, 1996, published as WO96/27976 Sep. 12, 1996.
BACKGROUND OF THE INVENTION
The invention is in the field of electronic reproduction technology and is directed to a method and to an apparatus for producing a rastered gray composite proof with a black-and-white recording device, for example a black-and-white printer, for advance monitoring of a color print. What is understood by gray composite proof is an advance impression called a proof in which the color values of the four color separations "cyan", "magenta", "yellow" and "black" are united to gray scale values equivalent to the brightness.
For exposing rastered color separations "cyan", "magenta", "yellow" and "black" for color printing with an electronic recording device, also called a recorder or exposer, color separation values for the individual color separations are first produced. The color separation values are then supplied to a raster generator in which they are converted according to a raster function to form a bit map whose control bits are used for the pixel-by-pixel activation and deactivation of an exposure beam in the exposer in the pixel-by-pixel and line-by-line recording of the rastered color separations. The rastered color separations serve for manufacturing the printing forms for the later color printing.
In practice, proofs are produced for advance monitoring of the anticipated result in the color printing. The production of simple, rastered color proofs occurs, for example, with a color copier that is preceded by a raster generator. Simple, rastered black-and-white proofs for the individual color separations are printed, for example, with a black-and-white printer that is likewise preceded by a raster generator.
The advance monitoring of the anticipated result of a color printing on the basis of simple black-and-white proofs for each color separation does not allow a definitive statement about the quality of the later color printing since the brightnesses on the printed black-and-white proof do not correspond to the brightness impression produced by the corresponding inks in the color printing.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to improve a method and an apparatus for producing a proof such that a reliable advance monitoring of the anticipated result in the color printing becomes possible on the basis of a rastered gray composite proof.
According to the method of the invention for producing a rastered gray composite proof for advanced monitoring of color printing of the color image, color separation values are generated of color separations "cyan", "magenta", "yellow" and "black" of a color image. A recording material is divided into pixels. The color separation values are converted according to a raster function into control bits in the form of a bit map allocated to the pixels. The proof is recorded pixel-by-pixel and line-by-line on the recording material, the control bits of the bit map determining during the recording whether the pixels are recorded or are not recorded as raster points or parts of a raster point. The gray scale values to be recorded on the gray composite proof are corrected to different percentage parts for the color printing compared to gray scale values of the chromatic printing inks "cyan", "magenta" and "yellow" represented by the color separation values, the different percentage parts respectively corresponding to a subjectively sensed brightness impression of the chromatic printing inks "cyan", "magenta" and "yellow" with reference to the printing ink "black". The color separation values of the chromatic printing inks "cyan", "magenta" and "yellow" are converted by different raster functions into three individual bit maps such that the recorded pixels of the chromatic printing inks "cyan", "magenta" and "yellow" lie next to one another on the recording material. The individual bit maps of the chromatic printing inks "cyan", "magenta" and "yellow" are united to form an overall bit map. The control bits
REFERENCES:
patent: 4703318 (1987-10-01), Haggerty
patent: 4743962 (1988-05-01), McCormick
patent: 5029107 (1991-07-01), Lee
patent: 5220417 (1993-06-01), Sugiura
patent: 5278678 (1994-01-01), Harrington
patent: 5323247 (1994-06-01), Parker et al.
patent: 5457772 (1995-10-01), Shannon
patent: 5640254 (1997-06-01), Sexton
Kohler Thomas
Lang Klaus
Netthorn Andreas
Brinich Stephen
Linotype-Hell AG
Moore David K.
LandOfFree
Method for generating a screened gray proof having gray values f does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for generating a screened gray proof having gray values f, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for generating a screened gray proof having gray values f will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2401909