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May 2003
701P40210
Xerox Document Services Platform

Color Management

Guide

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   Summary of Contents for Xerox DocuColor 2045

  • Page 1: Color Management

    May 2003 701P40210 Xerox Document Services Platform Color Management Guide...
  • Page 2 SWOP® is a registered trademark of SWOP, Inc. While the information in this Guide is correct at the time of this publication, Xerox reserves the right at any time to change the information without notice. Changes are made periodically to this document. Changes...
  • Page 3: Table Of Contents

    ICC standard path ......2-3 Xerox enhanced path ......2-4 CMYK Native path .
  • Page 4 Characterization ......... . 3-1 Tips for use of Xerox Qualified Stocks ....3-3 Calibration process overview .
  • Page 5: Introduction

    DocuSP color tools. Multiple print engines The DocuSP controller includes color management tools for the DocuColor 2045/2060/6060 and iGen3 Digital Production Presses. This guide provides general color management information for the DocuSP controller; also, printer-specific information is noted where necessary.
  • Page 6: Conventions

    Bold: Boldface type is used for the following: – Directory paths; for example, “Browse to the Color – Text that you enter; for example, "Enter purple or Xerox." – Calling attention to text that is particularly important; for – Introductory words or phrases that begin items in a list; for •...
  • Page 7: Customer Support

    Customer Support For service and software support, dial 1-800-821-2797. This number is enabled for TTY bridges. To reach Xerox Documentation and Software Services, dial 1-800-327-9753. Color Management Guide Introduction...
  • Page 8 Introduction Color Management Guide...
  • Page 9: Docusp Color Management

    Color management is a process of attempting to match colors across input (scanners, digital cameras), display (computer monitors), and output devices (color printers). Hardware devices such as Spectrophotometers for calibration and software tools such as color profiles, tone reproduction curves (TRCs) and color tools are used to match or adjust color to achieve a quality color image.
  • Page 10: Color Workflows

    Color path charts Jobs take one of five paths through the DocuSP controller. Whenever possible, you should use the Xerox Enhanced Path which provides the highest quality color for incoming SWOP™ CMYK color and faster RIP speed.
  • Page 11: Icc Standard Path

    Figure 2-1. Simplified DocuSP Color Workflow ICC standard path Jobs undergo a color transformation to an independent color space before color transformation to the DocuSP print engine CMYK color space. This path requires more RIP time as the color is transformed from Input (such as RGB or input CMYK) to Profile Connection Space (PCS) to output CMYK or SWOP™...
  • Page 12: Xerox Enhanced Path

    • A Xerox stock is programmed for the job • A non-Xerox stock that is a member of an unaltered Xerox color group is programmed for the job • A Xerox output color profile, included with the system, has...
  • Page 13: Cmyk Native Path

    PANTONE® calls, the PANTONE® path is invoked. The job’s color information is processed using a pair of Look Up Tables (one for Coated and one for Uncoated) and then passes directly to the printer output, bypassing all other color processing except for User TRCs. Color Management Guide...
  • Page 14: Color Manager

    New Stock Destination color profiles are required for each stock or color group. Stocks added from the catalog (Xerox Qualified Stocks) will automatically be placed in the proper color group. New custom stocks will automatically be placed in the default color group.
  • Page 15: Color Profiles

    Print engine specific mode Selected at the queue level, the print engine or product specific mode is unique to each Xerox color print engine and optimizes performance for that print engine. Print engine specific mode provides the best possible default color interpretation and rendering values for the widest range of images.
  • Page 16 Gray Source Destination ICC Profile Front/ Back Lightness Contrast Saturation Color Cast (all) TRCs Press Color Emulation Table 2-2. DocuColor 2045/2060/6060 mode default Queue Property Rendering Intent RGB Source CMYK Source CMY Source Gray Source Destination ICC Profile Front/ Back...
  • Page 17: Xerox Consistent Color Mode

    Default Source files provide output that looks similar when submitted from the DocuSP to a compatible Xerox color print engine, currently the DocuColor 2045/2060/6060 and the DocuColor iGen3. Table 2-3. XCC mode default and override settings...
  • Page 18: Custom Color Mode (default)

    DocuSP color management Table 2-3. XCC mode default and override settings Queue Property Press Color Emulation Custom color mode (default) Selected at the queue level, Custom Color mode allows users with a high level of color management skills to make specific color adjustments using industry standard color tools.
  • Page 19: Expert Color

    • Black Overprint compensates for the band of white that may appear when black text is printed directly on top of a color. NOTE: Black Overprint produces sometimes-unexpected results using iGen3, due to its unique technology. Therefore, you should avoid using this feature on the iGen3. •...
  • Page 20: Print As Grayscale

    DocuSP color management – Output Print as grayscale Print as grayscale converts color content to gray. Refer to on-line help for the details, as well as for information on billing. Spot color editor DocuSP has a built-in color lookup table to map incoming spot color (PANTONE®...
  • Page 21: Opi (open Prepress Interface)

    The Spot Color Editor tab is covered in more detail in Chapter 4: Using Color Tools. OPI (Open PrePress Interface) OPI is a process to replace low-resolution images with high- resolution images at RIP time. This speeds up job submission time because you can submit a job with the low-resolution images much faster than with high-resolution images.
  • Page 22 DocuSP color management 2-14 Color Management Guide...
  • Page 23: Stock Management And Calibration

    DocuSP comes with 3 pre-installed color groups, containing Xerox Qualified Stocks. Xerox Qualified Stocks are automatically part of one of the pre-installed color groups and have a destination profile pre-assigned to them; therefore, they do not require characterization.
  • Page 24 Qualified Stocks may be removed from your Stock Library, but not from the Stock Catalog. However, you may add new, non- Xerox stocks to the existing stock groups. It is advantageous to do so, as long as the new stocks share the same white point value.
  • Page 25: Tips For Use Of Xerox Qualified Stocks

    Tips for use of Xerox Qualified Stocks Here are some general tips for using Xerox Qualified Stocks: • You are able to modify certain attributes of Xerox Qualified Stocks. Some fundamental attributes cannot be modified, as they affect color processing.
  • Page 26: Calibrating The Docucolor 2045/2060/6060 Family

    Stock Management and Calibration Calibrating the DocuColor 2045/2060/6060 family For the DC 2045/2060 and 6060, you should calibrate at least once or twice a day or more often when printing jobs that are “color-critical.” The default number of prints of the calibration targets is 5 for the DC 2045/2060/6060 family.
  • Page 27 Stock Management and Calibration This procedure is more likely to be necessary for iGen3 due to image-to-page registration errors, but may also be applicable for DC20xx/60xx printers. Figure 3-1. Calibration target and whitespace Figure 3-2. Calibration step 1 Color Management Guide...
  • Page 28 Stock Management and Calibration Figure 3-3. Calibration step 2 Figure 3-4. Calibration step 3 Color Management Guide...
  • Page 29: Stock Management Hints And Tips

    Stock Management hints and tips General Stock Workflow Setups Unspecified Stock Name Model Setup The settings outlined in this section use the “Unspecified Stock Name” model. This workflow is best for customers that have a limited number of stocks and want very consistent color outcomes with very easy system operation.
  • Page 30: Three Stock Model Setup

    Unspecified stocks on the system. Three Stock Model Setup This set-up utilizes three stock groups to represent all the stock you use. Three Xerox created groups represent Bright White, White, and Other substrates. The purpose of this set-up, as compared to the Unspecified workflow, is to account for common whiteness differences in stocks by using only three groups.
  • Page 31 In this set-up, you add any Non-Xerox stocks you wish to print on to one of the three groups. • Bright White (Greater than 95) • White (93.7 > L* <= 95) • Other (L* <= 93.7) NOTE: White point values can be found on the ream wrapper and/or from the manufacturer.
  • Page 32 Stock Management and Calibration Table 3-1. DocuSP Sample Stock Grouping Group Paper Name Name Bright Color Expressions 98 Bright White Cover White Color Expressions 98 Bright White Cover Color Expressions 98 Bright White Cover Digital Color Colotech Natural White Color Expressions+ 96 Color Expressions+ 96 Color Expressions+ 96 Color Expressions+ 96...
  • Page 33: Custom And Colored Stock Hints

    A simple way to determine which color group would be best for your specific colored stock is: 1. Add your stock to a tray. 2. If desired, within [Printer Manager: Trays], select the option to force feed from the tray. Alternatively, you can just program a specific stock for your job.
  • Page 34 9. Right-click on the job in Job Manager and select [Proof] from the context menu. The job is released to RIP. 10. Retrieve your print from the output tray of your printer. 11. Repeat steps 4 through 10 twice, selecting a different Destination profile each time.
  • Page 35: Using Color Tools

    • Automatic Color Management provides high-quality consistent color with routine calibration and by applying Xerox Consistent Color Mode or Print Engine Specific Mode at the queue level. • Simple Color Management provides high-quality consistent color with routine calibration and easy to use color tools to adjust color cast using simple slider bars for lightness, contrast and saturation.
  • Page 36: Basic Color Tools

    Using color tools Queues of this type provide operators a path to print high-quality color output without requiring a detailed knowledge of color profiles. The profiles are pre-set prior to operator intervention. Basic color tools Basic color tools can be applied at the queue, job or page level. The adjustments are made on all of the colors and are additive if more than one adjustment is made on an image.
  • Page 37: Image Quality Tools

    – Cyan vs. Red - moving the slider bar towards cyan adds – Magenta vs. Green - moving the slider bar towards – Yellow vs. Blue - moving the slider bar towards yellow Image quality tools Image quality tools can be applied at the queue, job or page level.
  • Page 38: User Tonal Reproduction Curves (trcs)

    If trapping is applied at the application, do not trap at the controller. • Black overprint – DocuColor 2045/2060/6060 black overprint prevents the – DocuColor iGen3 lays the colors onto the image in a • Anti-aliasing reduces the jagged appearance of curves and lines in text and line art.
  • Page 39: Expert Color Tools

    Create User TRCs to make and save color adjustments that can be applied to jobs. The creation of User TRCs should be performed by users with a high level of color knowledge. For example, create a TRC that compensates for jobs submitted from a specific device that generates a consistent magenta tint.
  • Page 40 Using color tools Selecting a source color profile places the image on that source profile’s color processing path when there is no embedded profile for the image. • Output color allows you to select profiles that maximize the color potential of the output print engine. –...
  • Page 41 Using color tools Figure 4-7. Interpolation methods The interpolation methods that may be selected include: Nearest Neighbor Interpolation: A method used to scale image data (pixels) from one resolution to another. The output pixel value is simply the value of the input pixel closest to the output location.
  • Page 42 Using color tools – Output allows you to select the output profiles. Filtered Interpolation is a method used to scale image data (pixels) from one resolution to another. The output pixel is calculated by passing the neighborhood of the input pixel through the filter to determine the output pixel.
  • Page 43 Object Type Images Graphics Text Color Management Guide For CMYK images, using System Specified (default) rendering is perfectly acceptable. The Saturation intent for CMYK 4x4 LUT is derived from the Relative Colorimetric intent. In general, use Relative Colorimetric to match a proof. Use the other rendering intents based upon preference.
  • Page 44: Spot Color Editor

    Using color tools Spot Color Editor The Spot Color Editor window displays a list of spot colors recognized by the system. The list can display PANTONE® Colors, Edited PANTONE® Colors and Custom User Colors. The operator can view the properties of all colors, edit all colors and delete custom colors.
  • Page 45: Open Prepress Interface (opi)

    – Custom • Color Type (icon): A column that displays a tool tip (if present) when you pass the mouse pointer over the graphic icon. • CMYK: A column that contains numerical values corresponding to the respective values of Cyan, Magenta, Yellow, and Black that are present in each spot color.
  • Page 46 Using color tools This process works as follows: 1. An image repository is created on the DocuSP controller that contains all of the full-resolution images that will be employed by the document creators. 2. An OPI Search path is created in the Setup menu so that the DocuSP controller knows where to find a local copy of the full-resolution tiff image.
  • Page 47: Using Print Engine Specific Mode

    Using XCC (Xerox Consistent Color) mode Use XCC mode for those jobs that have no unique color requirements and may be printed on other Xerox print engines. Color Management Guide Using color tools...
  • Page 48 Using XCC produces an image of the same document that is similar when it is submitted to any Xerox color print engine running in XCC mode. XCC standardizes the way the DocuSP controller interprets unknown input color profiles and standardizes the conversion through a Xerox standard output profile.
  • Page 49: Troubleshooting

    A good place to start troubleshooting is to identify the image path the job took through the system. Determine whether the job took the Xerox Enhanced, Standard, Fast Reprint or Native path and submit the job using another path. If the job successfully prints with satisfactory color results, the problem is isolated to a particular path.
  • Page 50: Things To Remember

    Calibration and User TRCs are applied in hardware. They do not affect RIP performance or color pathway. • The Xerox Enhanced Path always provides improved RIP performance and better image quality. • Using pre-installed profiles and Look Up Tables is sufficient for most customer jobs and most stock.
  • Page 51: System Specified Defaults

    A. System Specified defaults This section details the various Color Management tools and their system-specified, default states. Management Color Mode Lightness Contrast Color Cast: • • • Trapping Image/Graphic Trapping Black Overprint Anti-Aliasing Source Color Output Color- halftone Color Management Guide Table A-1.
  • Page 52 System Specified defaults Management Output Color: Image Resample: Destination Profile Emulation Rendering Intent: • • • • • Table A-1. Color tool DC 2045/2060/6060 • Bi-linear • Filtered • Nearest Neighbor • Smart System Specified • Images - Relative Colorimetric Saturation •...
  • Page 53: Glossary Of Color Management Terms

    Calibration is a process that enables the user to measure the printer’s output against a known standard, by using a Spectrophotometer to scan test patterns. The process enables the user to adjust for “drift” in the color response of the printer and achieve consistent results. CIELAB A standard color space model defined by the Committee Internationale de l’Eclairage, an international standards...
  • Page 54 The complete range of colors a device can produce. Most printers have unique gamuts compared to other printers. Often, however, the printer can emulate the output of a different printer through use of a Color Space Transformation. Gray Component Replacement: the process of removing the graying component, or dirtying color, from a color and replacing it with black.
  • Page 55 Saturation A rendering intent that maps RGB CMYK to CMYK. The G is the printer’s G, the B is the printer’s B, and the R is a saturated Red. Source Profile The color profile with which the job was created at the client workstation prior to submission.
  • Page 56 Glossary Of Color Management Terms Tone Reproduction Curve. TRCs may be created and stored by users who wish to achieve certain effects on a consistent basis. User TRCs can be applied to all jobs, including those that originate as Reprint files. Uncoated Uncoated defines whether a stock has been coated or was left uncoated.
  • Page 57 Index Assign profile 2-6 Associations tab 2-6 Basic color tools 4-2 Bi-linear Interpolation 4-7 Calibration process overview 3-3 Calibration target tips 3-4 Calibration targets DC 20xx/60xx family 3-4 DC iGen3 3-4 Characterization 3-1 CMYK Native path 2-5 Color manager 2-6 Color paths 2-2 Color profiles 2-7 Color Tools...
  • Page 58 Fast reprint path 2-5 Halftones 4-6 ICC standard path 2-3 Image quality tools 4-3 Image Resample 4-6 New Color group 2-6 New stock 2-6 Open PrePress Interface 4-11 Open PrePress Interface (OPI) 2-13 PANTONE path 2-5 Print engine specific mode 2-7, 4-13 Queue Overrides 2-1 Rendering 4-8 Rendering intent 2-12...
  • Page 59 Troubleshooting 5-1 Unspecified Stock Name Model setup 3-7 User TRCs 2-7, 4-4 XCC mode using 4-13 Xerox consistent color mode 2-9 Xerox Qualified Stocks tips for use 3-3...

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