Xerox 701P40210 User Manual

May 2003

701P40210

Xerox Document Services Platform

Color Management

Guide

Xerox Corporation Global Knowledge and Language Services 800 Phillips Road Building 845-17S Webster, New York 14580 USA

allowed by statutory or judicial law hereinafter granted including without limitation, material generated from the software programs that are displayed on the screen such as styles, templates, icons, screen displays, looks, and so on.

all names identifying numbers used in connection with Xerox products mentioned in this publication are trademarks of XEROX CORPORATION. All non-Xerox brands and product names are trademarks or registered trademarks of their respective companies. Other company trademarks are also acknowledged.

This product includes software developed by the Apache Software Foundation (http://www.apache.org/).” 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 and technical updates will be added in subsequent editions.

1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-1

Assumptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

Multiple print engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

About this guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2

Related documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2

Customer Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3

2. DocuSP color management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-1

Queue overrides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1

Color workflows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2

Color path charts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2

ICC standard path . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3

Xerox enhanced path . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4

CMYK Native path . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5

Fast Reprint path . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5

PANTONE® path . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5

Color Manager . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6

Associations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6

Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6

New Stock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6

Assign profile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6

New color group (stock group) . . . . . . . . . . . . . . . . . . . . . 2-6

Color profiles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7

User TRCs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7

Color tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7

Print engine specific mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7

Xerox consistent color mode . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9

Custom color mode (default) . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10

Color adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10

Image quality tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10

Expert color . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-11

Print as grayscale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-12

Spot color editor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-12

OPI (Open PrePress Interface) . . . . . . . . . . . . . . . . . . . . . . . . 2-13

DRIs (Display Resolution Images) . . . . . . . . . . . . . . . . . . . . . . 2-13

3. Stock Management and Calibration. . . . . . . . . . . . . . . . . . . . . . . .3-1

Color Manage me nt Gui de i

Table of contents

Characterization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1

Tips for use of Xerox Qualified Stocks . . . . . . . . . . . . . . . . . . . . 3-3

Calibration process overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3

Calibrating the DocuColor 2045/2060/6060 family . . . . . . . . . . . 3-4

Calibrating the DocuColor iGen3 . . . . . . . . . . . . . . . . . . . . . . . . 3-4

Calibration target tips . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4

Stock Management hints and tips . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7

General Stock Workflow Setups . . . . . . . . . . . . . . . . . . . . . . . . . 3-7

Unspecified Stock Name Model Setup . . . . . . . . . . . . . . 3-7

Three Stock Model Setup . . . . . . . . . . . . . . . . . . . . . . . . 3-8

Custom and Colored Stock hints . . . . . . . . . . . . . . . . . . . . . . . 3-11

4. Using color t oo ls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-1

Using Custom color mode (default) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1

Basic color tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2

Image quality tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3

User Tonal Reproduction Curves (TRCs) . . . . . . . . . . . . . . . . . . 4-4

Expert color tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5

Spot Color Editor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10

Understanding the Spot Color Editor window . . . . . . . . 4-10

Open PrePress Interface (OPI) . . . . . . . . . . . . . . . . . . . . . . . . 4-11

Using Print Engine Specific mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-13

Using XCC (Xerox Consistent Color) mode . . . . . . . . . . . . . . . . . . . . 4-13

5. Troubleshooting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-1

Image paths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1

Things to remember . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2

A. System Specified defaults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A-1

B. Glossary Of Color Management Terms . . . . . . . . . . . . . . . . . . . . .B-1

ii Color Management Guide

Assumptions

1. Introduction

This guide is a reference to the DocuSP controller color management features. The DocuSP controller serves as the digital front end for preparing and processing jobs to print on Xerox color print engines.

The DocuSP operator uses the information in this guide to enhance the use of the color management tools to achieve quality color output.

This guide assumes that the DocuSP operator is familiar with the DocuSP controller and the attached print engine, and is also familiar with color printing.

Refer to the DocuSP on-line help system for procedures on how to use the DocuSP color tools.

Multiple print engines

The DocuSP controller includes colo r 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.

About this guide

Before you read in this guide, become familiar with its contents and conventions.

Color Manage me nt Gui de 1-1

Introduction

Conventions

This guide includes the following conventions:

• Angle brackets: Variable information that is displayed on your window or that can be entered as part of a command line is enclosed within angle brackets. Examples include "Unable to copy <filename>;" “set –p <printer>.”

• Square brackets: Square brackets are used fo r the following: – Names of menu options that you select; for example,

[Printer Default]

– Names of buttons that you select; for examp le , [OK] and

[Cancel]

– Names of text boxes, list boxes, and fields; for example,

"the [From] text box," "the [Directories] list box," “the [Color Source] field”

• 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 wor ds or phrases t hat begin items in a list; for

• Note: Notes are hints that help you perform a task or understand the text. Notes are presented in italics, in separate paragraphs. Example:

NOTE: You cannot submit a job unless the printer is connected to your workstation.

Customer Support

Introduction

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 Manage me nt Gui de 1-3

Introduction

1-4 Color Management Guide

2. 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.

Spectrophotometers are used to calibrate data for the print engine. Calibration da t a i s use d to ad j ust co lor ba la nce for st ock by halftone.

Color manageme nt softw a re conv erts RGB and CMYK input color profiles to the color gamut of a specific output device. DocuSP supports the traditional CMYK workflow as well as the ICC Profile workflow.

Queue overrides

TRCs and other color tools allow you to make custom color adjustments, fine tuning the color image.

DocuSP provides the software color management tools you can use to produce quality color output.

Refer to the DocuSP on-line help system for detailed informat ion and step-by-step usage procedures for all tools and processes presented in th is guide.

An override can be set for ma ny of the queue properties in Queue Manager. A selected override property is applied to all jobs submitted to that queue, regardless of job or job ticket settings.

Color Manage me nt Gui de 2-1

DocuSP color management

Color workflows

A color image follows a path as it is converted from an input color profile to the output CMYK of the print engine. Factors that determine the path are:

• the characteristics and type of the input profile

• conversions needed for the output profile of the print engine

• enhancements made by you, the user

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.

The color path chart (see Figure 2-1. Simplified DocuSP Color Workflow) displays the paths different documents take as they move through the DocuSP color management system and are processed for print.

The paths are:

• ICC Standard Path

• Xerox Enhanced Path

• CMYK Native Path

• Fast Reprint Path

• PANTONE® Path

2-2 Color Management Guide

DocuSP color management

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™ CMYK. The K channel will not be preserved for incoming CMYK data.

The chief benefit of using this path is its ease of use. The following conditions guarantee a job follows the ICC

standard path:

• A user output profile has been assigned to the job.

• A color adjustment (lightness, co ntrast, satu ration, color cast, trapping, black o verprint, or anti-aliasing ) has been set for t he job.

Color Manage me nt Gui de 2-3

DocuSP color management

• The incoming job contains embedded profiles that result in

Xerox enhanced path

Incoming RGB or CMYK data uses the DocuSP Xerox Enhance d Path Look Up Table (LUT) or Emulation LUT when performing the SWOP™ CMYK to DocuSP print engine CMYK transformation.

Benefits of using this p ath include:

• Faster RIP time via use of the LUTs as contrasted with the

• This path preser ves the Black (K) channel and Black

Look Up Tables provide a quick, effective translation from the source space to the specific printer’s CMYK space. These tables are faster because the CMYK values are translated directly to output space, instead of fi rst bein g tra nsla ted to deviceindependent space and then to the print-engine-specific space.

the printer driver creating a Color Space Array (CSA) for the color data. These PDL instructions are honored by the system.

ICC Path.

darkness.

RGB data is converted using 3 x 4 LUTs. 4 x 4 LUTs provide direct CMYK to CMYK mapping, preserving

black. When pure black is passed thr ough a source profile (ICC profile path), it is converted to XYZ. Once in XYZ, ther e is no way for the color management system to know that the color was originally pure black. Thus, pure K is converted to a CMYK combination (Gray Component Removal, or GCR, is involved in this process). In contrast, the 4 x 4 tables recognize pure K and output the appropriate K for the source-to-destination mapping.

The following conditions guarantee a job follows the Xerox enhanced path:

• The incoming job is untagged and using a pre-installed output profile.

• 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 been assign ed to the job

2-4 Color Management Guide

DocuSP color management

CMYK Native path

Color management is performed within the application using DocuSP output color ICC profiles to create jobs composed with the DocuSP print engine CMYK color profile. These jobs are sent directly to the RIP with no color transformations, assuming you have not programmed any color adjustments.

Documents destined for this path MUST be designed using the appropriate CM YK color space for the DocuSP destination print engine. This is u sually achieved by using the CMYK destination profile for the destination media/engine combination.

Benefits of using this p a t h in clude:

• Fastest RIP performance of any of the paths

• Color will be consistent throughout, since the job is created and submitted expressly for the specific print engin e

Fast Reprint path

Fast Reprint jobs, accessed thr ough Reprin t Manager, are saved using “Print and Save” or “Save” commands when processing the job. Fast Reprint jobs do not require re-RIPping. Color management properties are se t prior to saving t he job.

The only color change that can be applied to a job on the Fast Reprint path is a User TRC.

Benefits of using this p a t h in clude:

• No need to re-submit jobs

• Fast print times (achieving engine-rated speed) since the RIP is bypassed on reprint

• No need to reset Color Management properties

NOTE: Calibration TRCs and User TRCs may be applied to the reprint job, since TRC processing is done in the hardware.

PANTONE® path

An incoming job is scanned by the controller and, if the job contains PANTONE® calls , the P ANT ONE® pat h 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 pr inter output, b yp assing all other co lor pro cessing except for User TRCs.

Color Manage me nt Gui de 2-5

DocuSP color management

Color Manager

Color Manager provides access to color management tools for calibration, characterizat i on, assigning color profiles, managing color groups, creatin g and applying TRCs, and importing or exporting ICC profiles.

Associations

The Associations tab provides a list of stocks, their properties, date last calibrated, and the assigned profile.

Calibration

Calibration is used to return the print engine to a standard condition insuring color consistency for each stock or color group. For more in-d epth information regarding calibratio n, see chapter 3.

New Stock

Destination colo r 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.

Assign profile

Each stock is automatically assign ed to a profile based on its color group.

Color profiles can be assigned to any stock or color group, including pre-defined stocks.

New color group (stock group)

Stocks are assigned groups based upon their whitepoint. Any stock in the group can be calib rated, and the resulting TRCs are assigned to all stocks in the color group.

2-6 Color Management Guide

Color profiles

DocuSP color management

NOTE: You should calibrate a stock that best represents the other stock in the group; therefore, you should calibrate using a stock that has a whitepoint at about the median of the stocks in the group.

It is recommended that most users confine their use of color groups to the 3 pre-installed groups. This method provides excellent color results with relatively little user intervention.

For a more in-depth discussion of color groups, see chapter 3: Calibration.

The Color Profiles tab provides a list of color profiles (both source and destination) with their descriptions.

User TRCs

Color tools

Print engine specific mode

User Tone Reproduction Curves (TRCs) provide the skilled user with a tool for adj usti ng the indivi dual CMYK co lor sep a rati ons i n an image and saving those adjustments for use on other images.

The User TRCs tab provides a list of user-created TRCs and allows you to cr eate new TRCs.

Color tools allow you to make adjustments that impact the color characteristics of a print job. Color tools can affect jobs or queues, if assigned at the controller, or can be assigned by an application at the client workstation.

Selected at the queue level, the print engine or product specific mode is unique to each Xerox color print engine and optimizes performance fo r that print engine. Print engi ne specific mode provides the best possible default color interpretation and rendering values for the widest range of images.

Color Manage me nt Gui de 2-7

DocuSP color management

T able 2-1. DocuColor iGen3 Digital Production Press

Queue Property Queue Setting

Rendering Intent Relative Colorimetric RGB Source sRGB

mode default property settings

CMYK Source CMY Source

Gray Source Destination ICC Profile Front/

Back Lightness 0 Contrast 0 Saturation 0 Color Cast (all) 0 TRCs None Press Color Emulation None

SWOP System Specified

System Specified (pre-installed and optimized for the iGen3)

™

Tabl e 2-2. DocuColor 2045/2060/6060 mode defa ult

property settings

Queue Property Queue Setting

Rendering Intent Relative Colorimetric RGB Source sRGB CMYK Source

CMY Source Gray Source

Destination ICC Profile Front/ Back

Lightness 0 Contrast 0 Saturation 0 Color Cast (all) 0

SWOP System Specified

System Specified (pre-installed and optimized for theDC20xx/ 60xx)

™

2-8 Color Management Guide

Tabl e 2-2. DocuColor 2045/2060/6060 mode defa ult

Queue Property Queue Setting

TRCs None Press Color Emulation None

Xerox consistent color mode

Selected at the queue level, Xerox consistent color mode standardizes the print engine response to undefined color spaces by assigning them default source files. De fault 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.

DocuSP color management

property settings

Table 2-3. XCC mode default and override settings

Queue Property Queue Setting Applicability

Rendering Intent Images

Rendering Intent Text

Rendering Intent Graphics

RGB Source XCC Mode RGB Default CMYK Source

CMY Source Gray Source

Destination ICC Profile Front/Back

Lightness 0 Override Contrast 0 Override Saturation 0 Override

Relative Colorimetric Default

Pure Default

Saturation Default

SWOP System Specified Default

System Specified Override

™ Coated

Default

Color cast (all) 0 Override TRCs None Override

Color Manage me nt Gui de 2-9

DocuSP color management

Table 2-3. XCC mode default and override settings

Queue Property Queue Setting Applicability

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.

Skilled users create queues with specific color properties, defaults and overrides. Jobs sent to these queues are assigned the queue properties automatically, improving the flow of jobs through the DocuSP controller and reducing the adjustments required on a standard set of color jobs.

Color adjustments

Color tools provide a m eans for you to make adju stments in colo r images.

None Override

• Lightness controls the relative brigh tness or darkn ess of the color image.

• Contrast is the ratio between the light tones and dark tones in an image.

• Saturation controls the strength or purity of the color imag e.

• Color Cast adjustments provide you with the ability to increase or decrease the amount of a single color in an image.

• User TRCs are created to provide a consistent color rendering based upon a given set of properties. TRCs are saved and appl ied to jobs.

Image quality tools

Image quality tools provide you a means to improve image quality.

• Trapping compensates for misregistration that creates white gaps and shifted hues.

2-10 Color Management Guide

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