Abstract: Disclosed herein are optimal or near optimal algorithms implemented as software tools that will allow the user/machine to identify optimal media out of the job set automatically. There are at least two main process steps to the exemplary embodiment. The first step involves the off-line characterization of the printing/image rendering system that will be used to extract the principal basis vectors from the experimental data. The second step involves the run-time mode, in which the pre-characterized basis vectors are used in conjunction with an optimal algorithm that will identify the media for re-calibration/re-characterization from the group of media set that the customer is interested to print. The optimal algorithm performs the combinatorial search every time the customer wishes to select the media. Once the optimal media is selected, the customer or the machine can print color patches (which are also optimal set) and execute the rest of the processing to reconstruct the best color management LUTs.

Abstract: A read module includes: a light source that applies light to an original to read an image; a photoelectric conversion section that converts reflected light from the original into an image signal of the image; and a connector to be electrically connected to a controller connector in a controller. The connector has a plurality of terminals placed side by side in a predetermined direction. The plurality of terminals includes an image signal output terminal section that outputs the image signal to the controller and a power terminal section that inputs electric power for lighting the light source supplied from the controller to the read module. The power terminal section is placed in the proximity of one end of the plurality of terminals in the predetermined direction thereof. The image signal output terminal section is placed in the proximity of an opposite end in the predetermined direction thereof.

Abstract: Image control which requires time and troublesome work cannot be frequently performed, and image quality such as tonality reproducibility cannot be sufficiently stabilized in correspondence with constantly varying image characteristic of image forming apparatus. Accordingly, a density correction characteristic of image processing apparatus is controlled based on an image characteristic of pattern formed on a print sheet, then the image characteristic of pattern formed on an electrostatic drum is held as reference information. Upon normal image formation, a pattern is formed without an image formation area on the electrostatic drum, and the density correction characteristic is corrected based on the difference between the image characteristic of the pattern and the reference information.

Abstract: A method of detecting image quality defects in the output of an image output device includes the steps of generating a test pattern at a known time, analyzing the test pattern to generate image quality defect records, storing the image quality defect records in memory linked to a time stamp indicating known time when the test pattern was generated, repeating the generating, analyzing and storing steps at a plurality of different known times to generate a database of time stamped image quality defect records, reconstructing isolated defect data from each of a plurality of image quality defect records in the database, constructing cumulative defect data by probabilistic summation of the isolated defect data and analyzing the cumulative defect data using an image quality assessment/analysis engine.

Abstract: Graininess and calorimetric values of color patches formed by an image generating system using dark and light colored recording agents are input to calculate equiluminance contours. Color density decomposition is then performed based on the calculated graininess and equiluminance contours.

Abstract: The image processing technique of the invention receives an input image with an ID of a digital camera used for taking the input image (step S100) and performs color adjustment of the input image (step S110). The technique then specifies a color difference between an original image prior to the color adjustment and a resulting color-adjusted image after the color adjustment and generates a color correction profile based on the specified color difference (step S140). The generated color correction profile is stored in mapping to the ID of the digital camera (step S150). In response to input of each image with the ID of the digital camera, the generated color correction profile is attached to the each input image.

Abstract: In a printing system, before transmitting print data to a printer, a personal computer transmits a virtual printing start command to the printer. When the data received by the printer is a virtual printing start command, the printer performs a virtual printing operation until the printer receives a virtual printing end command from the personal computer. At the virtual printing operation, procedures are similar to those of an actual printing operation. However, at the virtual printing operation, sheets are not conveyed nor is a developing agent, such as ink and toner, adhered to the sheets by a printing unit. For example, the received print data is developed into a memory as an image data. When an error occurs during the virtual printing operation, the printer provides error information to the personal computer. Then, the personal computer displays the error information via a dialog box to a user.

Abstract: The color management system comprises a state-space based model for a pixel element in a dynamically varying color marking device. A sensor measures the color of the printed output for construction of a selected set of sensitivity functions representative of color output relating to inputs. The gradients of the sensitivity functions are extracted and used to develop the corresponding discrete multivariable state-space model of the pixel element. More particularly, the model is constructed from the Jacobian matrix characterizing a change in measured color output for a change in input color values of the pixel. Extension of modeling methodology for a single pixel is applied to multiple pixel elements.

Abstract: A gray balancing technique wherein gray balancing curves are determined by interpolating the primary color data values of color samples to determine discrete combinations of primary colors that substantially match predetermined targets, and performing a curve fitting procedure on the discrete combinations of primary colors to produce gray balancing curves.

Abstract: An image processing method includes creating a conversion table for converting a color in a device-independent color space into a color in a device color space based on a colorimetry result of a color patch output by a device. Creating the conversion table includes converting a color in a three-dimensional color space dependent on a device into a color in a four-dimensional device color space including black. Converting a color in the three-dimensional color space includes separating an input color in the three-dimensional device-dependent color space into color components of the four-dimensional device color space based on a gradation from the input color to black, using a black generation curve of a gray line set by a user and black generation curves set for individual primary colors of RGBCMY, and performing saturation-increase conversion on the color components in accordance with an amount of a black colorant.

Abstract: Process for the processing of image data which represent the color values of an image, to achieve optimal color reproduction of the image by an image reproduction system, especially by a photographic printer or photolab in response to the image data. In an exemplary embodiment, the image data which represent first positions in a first color space are received. The first positions are transformed into transformation positions which represent positions in a second color space; and the response of the image reproduction system to the image data is modeled with a model image reproduction system such that the model image reproduction system outputs the response as model positions which represent the color values produced by the model image reproductions system in response to the input of the image data as positions in a second color space.

Abstract: As a method of calibrating colors other than primary colors such as secondary colors, the contents of an ink color-separation table are reconstructed. However, it is difficult to reconstruct the ink color-separation table within the limitation of total ink amount permissible for a print sheet. Accordingly, a color patch corresponding to a signal value of a color to be calibrated is formed in a printer, then the signal value is calibrated based on a measured color value of the formed color patch and a target value corresponding to the signal value of the color to be calibrated, and calibration multidimensional table data is generated based on the measured color value of the formed color patch.

Abstract: An image region discrimination section in an image processing section, a characteristic signal calculation result obtained by hardware is subjected to macro-scoped correction and macro-discrimination by a processor. Further, in the image region discrimination section, a resolution and a signal bit number of a characteristic signals are decreased, the resultant characteristic signals is stored in a memory, and both a macro-discrimination result and the characteristic signals are synthesized to produce a final discrimination signal.

Abstract: A system and method for calculating the toner usage of a multifunction peripheral device using software and the compressed form of the raster image without uncompressing the image. The method enables the calculation of toner usage based on the statistics of actual colorant consumption while minimizing the approximation error. The compressed image data includes encoded data representing an image mapped onto a first color space. The received compressed image is analyzed to generate a pixel count of each color associated with the image corresponding to a color in the first color space. In the event of a different device color space, the pixel count is translated to a second color space, and an aggregate pixel count is calculated. When statistical data from actual operations is available, table data on the earlier usage is compared with the pixel count calculated, resulting in an approximate toner usage having low approximation error.

Abstract: A CCD is such that a single image sensing area is produced by performing exposure four times in four areas. Four correction circuits are provided in association with respective ones of the four areas. Four items of image data obtained based upon respective ones of the four areas are input to corresponding correction circuits, which apply a correction to prevent image disturbance at the area boundaries. One frame of image data is generated from corrected image data of respective ones of the areas and the image data is recorded on a memory card.

Abstract: A system, medium, and method calibrating gray data. The system calibrating gray data includes a transformation unit to transform red, green, and blue (RGB) data of a source device into transformed color data of a different color space using a color appearance model, and a calibration unit to map a chroma value of gray data, corresponding to the transformed color data, in the different color space to a predetermined value to generate calibrated color space data.

Abstract: An image forming apparatus which is capable of increasing printing efficiency by simplifying the calibration operation in time zones during which the frequency of use of the apparatus is high. An image forming apparatus has a plurality of calibration modes set in advance on a time zone-by-time zone basis for operating days. A printer controller determines a day of week and time of day, and selects one of the calibration modes associated with the day of week and time of day. The controller performs cumulative counting of sheets color-printed after a preceding calibration, and determines whether or not calibration in the selected calibration mode should be executed, from a cumulative count value of color-printed sheets and the selected calibration mode. The calibration in the selected calibration mode is executed in response to the determination that the calibration should be executed.

Abstract: Methods and systems for estimating single or multi-colored toner coverage on a printed page. One method includes generating color plane bitmaps corresponding to each color in a contone bitmap and calculating pixel coverage values for each of the color plane contone bitmaps. Another method includes receiving image data to be printed, generating color separations for the image data corresponding to available toner colors, printing each color separation on a printed page, scanning each printed page comprising the color separation and calculating toner coverage on each of the scanned printed pages.

Abstract: A system and method for testing scan and fax jobs includes receiving a job request from a user to scan or fax an image, the job request including one or more parameters, providing a test image based on the one or more parameters for the job request, generating a test job based on the identified test image and the one or more parameters for the job request, and processing the test job. Information regarding the result of the execution of the test job is stored. It is then determined if the job request can be executed correctly based on the stored information.

Abstract: A streak detection method and system in a fixed imaging array digital scanning system obtains image data from each of the plurality of rows in the at least one full color spectrum channel set of rows of positionally discrete sensors and integrates this data to produce an estimate of image data recorded by at least one clear channel row of positionally discrete sensors. A clear channel error signal is generated by the comparison to alert the operator to the presence of non-image data. The clear channel error signal may be refined to through a low pass column filtering process in order to filter out potentially erroneous clear channel error resulting from thermal, mechanical or other noise sources unrelated to image scanning. Stationary obstructions in the field of view of the imaging array, or defects in one or more sensors in the imaging array, are detected through this comparison which would otherwise appear repeatedly reproduced as streaks or lines in the reproduced output image.

Abstract: An image processing apparatus in which an appropriate color separation table is selected for an unexpected print medium. In plural color separation tables 108, maximum total color-material color discharge amounts are set to be stepwisely different. A ? correction table 109 is used upon correction of ? characteristics of the respective color-material colors regarding a print medium. A maximum total ink-amount calculation unit 110 calculates a maximum value of total ink amount for each color separation table 108 by using the ? correction table 109. A color separation table selector 107 determines a maximum value approximate to a value set by a maximum total ink-amount setting unit 106 from the calculated maximum values, and selects a color separation table corresponding to the determined maximum value. A color separation processor 102 performs processing based on the selected color separation table.

Abstract: A client controls printing of color chips (images for colorimetry) with a plurality of tones for individual color inks (printing colorants). The client acquires from a server a tone value correction table (color matching information) to match standard colors. The server can acquire the lightness data of color chips for individual inks and create the tone value correction table based on the lightness data of color chips of individual color inks and the lightness data of standard colors corresponding to the color inks, and subsequently send the color matching information to the client. As a result, it is easier to produce colors that match standard colors.

Abstract: If the grids of a color conversion table are simply downsampled, the way ink is used (the manner of the changeover in the value of a CMYKlclm signal) differs from that color conversion table before downsampling, there is a shift in the starting point of dark ink at the point of changeover of continuous tone ink, and a decline in image quality ascribable to downsampling of the color conversion table tends to occur. Accordingly, an original LUT is read in, a parameter for selecting a grid to be downsampled is set, a table of evaluation values for selecting a grid to be downsampled is created, a grid capable of being downsampled is selected by referring to the evaluation-value table, and table data that does not contain this grid is copied.

Abstract: A color output device is generally driven by at least three independent control signals for control of its response. A desired response in device independent color space is normally obtained by employing a cascade consisting of a characterization transform and calibration transform. The calibration transform transforms input control variables into output control variables that are directly used to drive the device. Input control variables can be transformed into intermediate control variables, which can be then mapped to output control variables utilizing a two-dimensional transformation. The two-dimensional calibration architecture provides improved control functionality and flexibility.

Abstract: A Micro-Electro-Mechanical System (MEMS) based Fabry-Perot array may be used as a spectral filter to light sensing array, such as a CCD or CMOS photodetector. Applying different voltages to the electrodes of individual Fabry-Perot cells within the array allows a gradient in the Fabry-Perot air gap across the Fabry-Perot array. In this manner the MEMS Fabry-Perot array serves as a spectral filter of light passing through the Fabry-Perot array to the photodetector array. Embodiments of the disclosed sensor, used with LEDs that emit light outside the photosensitivity range of a photoreceptor belt, may be used to measure spectral information from toned patches placed upon a photoreceptor belt within a marking system. Other embodiments of the disclosed sensor, used with LEDs that emit light of any wavelength, may be used to measure spectral information from toned patches placed by a marking system upon a non-photosensitive output substrate, such as an intermediate belt or paper.

Abstract: A Micro-Electro-Mechanical System (MEMS) based Fabry-Perot array may be used as a spectral filter to light sensing array, such as a CCD or CMOS photodetector. Applying different voltages to the electrodes of individual Fabry-Perot cells within the array allows a gradient in the Fabry-Perot air gap across the Fabry-Perot array. In this manner the MEMS Fabry-Perot array serves as a spectral filter of light passing through the Fabry-Perot array to the photodetector array. Embodiments of the disclosed sensor, used with LEDs that emit light outside the photosensitivity range of a photoreceptor belt, may be used to measure spectral information from toned patches and/or images placed upon a photoreceptor belt within a marking system. Other embodiments of the disclosed senor, used with LEDs that emit light of any wavelength, may be used to measure spectral information from toned patches or images placed by a marking system upon a non-photosensitive output substrate, such as an intermediate belt or paper.

Abstract: An improved color-image error diffusion process for use in conjunction with the operation of a multi-level, halftone, color-image output device. This process involves, first, performing output-device-dependent color error diffusion on color-image input data utilizing a halftone, output-device-dependent color palette containing output-device-dependent output color values. Thereafter, and with respect to the selection for pixel outputting of a pixel utilizing one of the output colors in the palette, and in relation to infeeding of that pixel to the output device for outputting, the process features applying a predetermined, dot-gain correction curve which corrects the infeed intensity value of the pixel in accordance with (a) the selected output color for the pixel, and (b) assessment of the pixel in terms of its association with a predetermined neighborhood pattern of adjacent pixels.

Abstract: A device, system and a method for soft proofing of an image before it is printed onto printed material, such that the colors of the image substantially reproduce, to the human eye, the colors as they should appear on the printed material.

Abstract: What is disclosed is a method for compensating for printer characteristics having a tone reproduction curve which is either too rough to be fitted by interpolation or which does not have a simple parametric function. The method comprising first placing a first set of control points on the tone reproduction curve such that each point is representative of the behavior of the curve in the vicinity of that point and fitting a first smoothed curve to the first set of control points. A subset of points belonging to the set of first control points along the first smoothed curve is moved, thereby indicating a desired change in that region of the curve of the original function. A second set of control points is generated from the set of moved first control points and the remaining unmoved first control points and a second smoothed curve is then fitted to the second set of control points. A differential function between the first and second fitted curves is then determined.

Abstract: The system for selecting a best device for rendering a color document involves first determining the types of color data included in the color document to be printed. Once the type of color data has been determined, the color characteristics are matched against the strengths of the available output devices to obtain a list of devices best suited for this particular color print job. At least one device from the list of best devices is selected and the color document is rendered onto the selected device. Preferably, the types of color data involved are determined by the mix of defined colorimetry and undefined colorimetry in the color document. Alternatively, the types of color data are determined by analyzing the colorspaces in the document (i.e., RGB, CMYK, LAB, XYZ, etc.), and the embedded profiles, if any, in the document (e.g., sRGB, SWOPCMYK, Euroscale).

Abstract: Methods and apparatus are disclosed for modifying the rendered output of a marking engine for a print job in progress. A marking engine commences printing print data for a print job. A parameter of a printed page of the print job is measured while the marking engine prints the print job. The measured parameter is compared to a reference, and the print data are modified before the print job completes, such that all subsequent portions of the print job are rendered with modified print data.

Abstract: Systems and methods are provided for characterizing laser beam process direction position errors in an electrophotographic device. Once the process direction position errors of a given beam laser beam system have been characterized, an image is adjusted or warped prior to being processed by the laser beam system to compensate for laser beam process direction position errors, e.g., bow and skew.

Abstract: When an output unit to produce output is specified through an instruction terminal 11 and original data is input to a color proof generation section 12, a color conversion section 13 acquires a color conversion parameter corresponding to the specified output unit from a color conversion information storage section 14 and performs color conversion processing for the original data so as to accomplish precise color reproduction in the specified output unit. A rasterizing section 15 expands the original data after undergoing the color conversion processing into raster data while using an enormous number of fonts in a font storage section 16. The raster data provided by the rasterizing section 15 is transmitted from a communication section 17 through a network 4 to the specified output unit. If a remote system 2 or 3, which receives the raster data, prints out on output unit 21 or 31, a color proof whose color is reproduced precisely can be provided.

Abstract: A scan method comprising a sensing photo module applicable in a scan apparatus for scanning a document is disclosed. The sensing photo module is equipped with photo sensors parallel to each other and detects the photo signal at every collection distance. The photo sensors extend horizontally and are positioned a line distance between the adjacent photo sensors. Under low operating resolution, the vertical resolution is increased by making the line ratio an integer, in order to solve the problem of color-quality loss due to a non-integer line ratio.

Abstract: The present invention provides a calibration method and circuit for outputting an average calibration value used in an image-capture apparatus. The calibration circuit comprises difference means accepting a plurality of digital signals from capturing a pixel of a calibration chart. The difference means is for operating each digital signal with subtracting a base value, and whereby filters any aberrant digital signal. Divider means accepts the digital signals for operating each digital signal with dividing a number of scanned times, and whereby prevents an operation of any signal from overflowing. Direct average means accepts the digital signals for summing the digital signals and then divides the number of scanned times, and whereby speeds a calibration operation.

Abstract: The present invention implements a CMYK to CMYK pre-transform in front of at least one printer to be clustered where the transform is designed to ensure that the printers addressed through the pre-transform have substantially identical output color for substantially identical input CMYK values. As one form of implementation a method is disclosed to build CMY to CMY 3D-LUTs and 1D-LUT for K using sensors in the field. Making use of a system LUT—CMY to CMY 3D-LUT and a K to K 1D-LUT—improves consistency and provides a coherent control strategy and a means to provide standardized input CMY and K values in a clustered environment so that single or multiple vendor DFEs see substantially identical CMYK values.

Abstract: A method for correcting for edge defects caused by print characteristics of a print engine includes printing a set of actual color patches corresponding to a desired set of colors; defining an edge region and a uniform area region in each of the patches; for each color patch in the set of actual color patches: determining a difference between color in the edge region of the patch and color in the uniform area region of the patch; and generating an edge response to adjust color output of the print engine in the edge region to substantially match color output in the uniform area region. The method can perform edge correction for any edge region of an image. In one embodiment of the invention, the edge region may be determined by a trap engine associated with the print engine and the method can provide correction for trap pixels.

Abstract: Systems and methods for dynamically generating a printer model database (PMDB) that is based on a printer driver. The printer model database is dynamically generated by automatically generating device independent print job options, semi-automatically generating device dependent print job options, and automatically generating a printer model database.

Abstract: Methods and systems used to automatically identify the marking process used for an image on a substrate based on spatial characteristics and/or color of the image. Image types which are classified and identified include continuous tone images and halftone images. Among halftone images separately identified are inkjet images, xerographic images and lithographic images. Locally adaptive image threshold techniques may be used to determine the spatial characteristics of the image.

Abstract: A method of preventing image degradation due to nonejecting nozzles of a recording head is provided for an inkjet recording apparatus for recording images by ejecting ink from plural nozzles disposed in the recording head. The method according to the present invention includes the steps of measuring and recording a pattern for checking an ejection state of the head, determining a nonejecting nozzle from the pattern, obtaining density distribution for each nozzle, and determining a complementary table for every nozzle from the density distribution in the nonejecting nozzle portion for performing different-color complementing.

Abstract: A method for color correction of an image having an insignia portion in a multi-module printer (10). A first color profile is calibrated for a four-color image. A second color profile is calibrated for a four-color image with a transparent toner layer on top of the insignia portion of the four-color image. The image data is then buffered in a color input band buffer (40) and processed through the first (50) and second (60) color profiles in a color management module. The processed image data is stored in an output band buffer (70, 80) corresponding to the image data processed through each color profile. Clear toner input band data stored in a clear toner input band buffer (30) is compared with the processed image data in each output band buffer (70, 80) to select an output signal (100) on a per pixel basis to send to the multi-module printer (10).

Abstract: A method permitting an end user to recalibrate a color reproduction device. The color reproduction device includes a device for converting the native color values of the scanner into a device independent color space, a test target, and the desired values of each patch of the test target. The method includes printing the test target and scanning it with a scanner that forms a part of the color reproduction device. The device compares the desired values with the values obtained from scanning the printed test target to obtain a set of adjustment values to compensate for drift in the output of the color reproduction device. The compensation emphasizes restoration of the overall gray balance of the color reproduction device and can be implemented by modifying the tone reproduction curves or the halftone process used in the color reproduction device.

Abstract: A method of determining substrate and ink compatibility includes providing a test pattern having a range of ink loading levels and including test features corresponding to at least one of text and graphics; identifying a substrate; identifying an ink set; printing the test pattern on the identified substrate using the identified ink set; selecting an ink loading level for at least one of the at least one of text and graphics using the test pattern; and generating a tone scale transformation for one or more ink colors of the identified ink set using the selected ink loading level for at least one of the at least one of text and graphics, the selected ink loading level for the at least one of the at least one of text and graphics being dependent on the identified substrate.

Abstract: A method of producing from a first device-dependent image data set, a second image data set matched to a real process, includes, by using inverse gamut mapping, transforming color values from the first image data set into color values of a device-independent color space and, by using gamut mapping, transforming these device-independent color values into the second image data set of an output device; and a color management method including the producing method.

Abstract: A printer or other marking engine includes a marking material transfer device, such as a photoreceptor drum or belt, that includes a plurality of pitches. Each pitch receives an individual color of marking material and conveys the marking material to a substrate. The marking engine forms a desired image in a main image area of the substrate using marking material from one or more of the pitches, and produces a target patch pattern for each of the pitches in a margin area located outside the main image area. A measuring device such as a spectrophotometer is used to measure each target patch pattern, and based on the measured values, an individual color calibration is performed for each pitch for use in a subsequent marking operation. The color calibration may include generating or modifying a tone reproduction curve for each pitch based on the measured values. The margin area may be later trimmed off, thereby removing the portion of the substrate on which the target patch pattern is formed.

Abstract: A method includes forming a plurality of test patches in an array of orthogonal rows. The test patches are formed by using at least one printhead in an imaging machine. Each of the test patches is associated with a respective one of a plurality of initial input color values. The array of test patches includes a plurality of rows of varied-input test patches and at least one row of first equivalent-input test patches. A respective output color value of each of the test patches is measured. At least one first mathematical relationship is generated based on the output color values of the at least one row of first equivalent-input test patches. A plurality of adjusted input color values are calculated for respective ones of the varied-input test patches. Each adjusted input color value is calculated based upon the generated at least one first mathematical relationship. A second mathematical relationship is computed between the adjusted input color values and the output color values.

Abstract: When an input color signal of a first color space is converted to a color signal of a second color space having a color reproduction range narrower than that of the first color space, it is determined whether a color signal that is outside the color reproduction range of the second color space having the color reproduction range narrower than that of the first color space exists within the input color signal of the first color space. If it has been determined that a color signal outside the color reproduction range of the second color space exists, the hue system of the color signal represented in the first color space is converted to the hue system of the color signal represented in the second color space having the narrower color reproduction range.

Abstract: A method for transforming device dependent color values [C1, M1, Y1, K1] of a first printing process into device dependent color values [C2, M2, Y2, K2] of a second printing process, the printing processes being characterized by color profiles setting the device dependent color values of the printing processes in a relationship with the device independent color values of the LAB or XYZ color space, includes determining, from the profiles of the printing process, a one-dimensional assignment function K2=f(K1), and describing the paper white of the first printing process by the color values [C2pw, M2pw, Y2pw, K2pw] of the second printing process. Pure gray colors from the first printing process having the device dependent color values [C1=0, M1=0, Y1=0, K1] are transformed into the device dependent color values [C2pw, M2pw, Y2pw, K2pw+f(K1)] of the second printing process.

Abstract: A method of applying a control strip having an appropriate size in accordance with the size of a print image is provided. Print image data is rasterized or RIP-processed in Step S1. Image layout data is acquired from the print image data in Step S2. The size of control strip image data is adjusted based on the image layout data in Step S3. The size of the control strip is determined to be a positive integral multiple of an ink key size, based on a previously established equation. Based on the size of the control strip image data, a previously prepared control strip having a maximum size is cut. The adjusted control strip image data and the print image data are combined together in Step S4. In Step S4, blank data are added to the left and right of the print image to extend the size of the print image to the size of the control strip.

Abstract: The system provides for controlling color reproduction of input color image data representing one or more pages or page constituents in a network having nodes (or sites). Each one of the nodes comprises at least one rendering device. The system distributes the input color image data from one of the nodes to other nodes, and provides a data structure (virtual proof) in the network. This data structure has components shared by the nodes and other components present only at each node. Next, the system has means for providing color calibration data at each node characterizing output colors (colorants) of the rendering device of the node, and means for producing at each node, responsive to the color calibration data of the rendering device of the node, information for transforming the input color image data into output color image data at the rendering device of the node. The information is then stored in the data structure in different ones of the shared and other components.