I have written Photoshop Astronomy to do just that. It is packed with tutorial examples that are specific to astronomical imaging. Each Photoshop step is explained in great detail. A beginner will see results immediately. But make no mistake; this is not a "Photoshop for Dummies". I have not avoided complex material or procedures. Quite to the contrary, I have included difficult, extended image-processing tasks along with the simpler ones. Once you see how even the difficult procedures are worked with my step-by-step examples, their "difficulty" vanishes.
There are many things within this guide that even seasoned digital imagers will find challenging and useful. I have also included explanations of how and why things work. "Do this" and "Do that" are not sufficient. It is my firm belief that to speak the language of image processing you must understand the meaning of its “words” and their syntax. I have seen this method work during the many seminars I have conducted for amateur astronomers across the United States.
Sky & Telescope review
It would take many months or even years to find and memorize all the information provided in the one-stop source.
AMONG THE MYRIAD computer programs used by astrophotographers, none is as popular or versatile as Adobe Photoshop. However, to take full advantage of the program's capabilities requires vast amounts of time. If a shortcut exists for mastering the tools and techniques needed to properly massage an astrophoto, R. Scott Ireland's new book Photoshop Astronomy is it.
Ireland, a Photoshop user since the mid-1990s, developed his book to help others understand and speak the Photoshop language. Everything you'll need to produce top-quality images is covered in intricate detail, from monitor calibration to complex layering and mosaicking techniques. Even better, the book includes a DVD with the image files used as examples throughout the book. Readers can walk through each step exactly as it is described.
Photoshop Astronomy starts with the tools you'll need for your digital darkroom, including choices for computer platforms, RAM considerations, hard dives, optical drives, video cards, USB hubs, and other peripheral devices. Ireland spends a great deal of time discussing computer monitors and specifically stresses the importance of color-calibration systems. "the best monitor in the world," he writes, "won't do you much good if it is not calibrated." Printers, scanners, and file formats are also discussed at length.
The chapters are arranged by image-processing themes and are ordered roughly by complexity. Chapter two contains exercises designed to familiarize readers with color space, color management, color profiles, and bit-depth. Chapter three deals exclusively with understanding an image histogram and how to interpret changes incurred to the tonal range when you are applying the Levels command. Next, the Curves function –quite possibly the most powerful tool in all of Photoshop–is explained.
After covering these basics, Ireland recommends that the reader skip to points of particular interest, though each chapter still builds upon the previous one and introduces new concepts. For example, many astrophotographers dedicate their observing time to one category of imaging, such as deep sky, lunar and planetary, or comets. A reader might assume that the sections on planetary imaging would be of little use to deep-sky astrophotographers. But I find that the techniques I use for planetary images can be just as useful for deep-sky photographs.
While I didn't always agree with Ireland's approach to various image-processing tasks, the reasoning for his decisions was always sound. Moreover, it should be noted that in cases where Photoshop cannot adequately perform a task, the author had no qualms about recommending other programs that can do the job.
Overall, it's hard to complain about anything in Photoshop Astronomy. Everything the author sets out to tackle is covered well, especially when the reader uses the images provided on the DVD to methodically follow each step. Ireland also freely admits (as does any good teacher) that he is still learning new tricks every day. Photoshop is such a powerful, evolving program that users always seems to be discovering new useful techniques that can further enhance their images.
While virtually all of Ireland's tips can be found or discovered on your own, it would take many months or even years to find and memorize all the information Ireland provides in this one-stop source. That makes Photoshop Astronomy worth its weight in gold ... or terabytes.
Sean Walker
Assistant editor, Sky & Telescope magazine
About the author
R. Scott Ireland has lived in South Florida since the age of six. His educational background includes a Bachelor of Fine Arts degree in music performance, and a Master of Business Administration Degree in finance. Scott has also passed the Uniform Certified Public Accountants examination, and he holds a ranking of Candidate Master in correspondence Chess from the U.S. Chess Federation.
As an avocation, Scott has pursued lifelong interests in Astronomy, nature photography and Chess. He is a past President and honorary life member of the Southern Cross Astronomical Society. The author.
Scott is a member of the Puckett Supernova Search Team, and was a co-discoverer of Supernovae 2003fd and 2004gw. He is also a member of IAVCEI (International Association of Volcanology and Chemistry of the Earth’s Interior) and Volcano Watch International.
The author: R. Scott Ireland.
Scott’s photographs have been published internationally in many books, textbooks and periodicals, and have appeared in various museum and gallery exhibits. His publication credits include Nature’s Best Magazine, Nature Photographer Magazine, the National Audubon Society Field Guide to Florida, the Peterson Field Guide to the Stars and Planets, Odyssey Magazine, Sky & Telescope Magazine, Introduction to Observing and Photographing the Solar System and Mercury Magazine.
Scott’s images of the Soufriere Hills Volcano on Montserrat were selected by University College, London for use in their volcano hazard mitigation literature being distributed to governments and volcanologists throughout the Caribbean. His images of the Mount St. Helens eruptions of October 2004 have been published and archived for scientific use by the Smithsonian’s Global Volcanism Program. Scott was a member of the National Geographic team sent to Arenal Volcano in Costa Rica to film the documentary entitled Volcano Hunters.
Two of Scott’s images were among the winners of the prestigious annual Nature’s Best Magazine international photo competition, and will be exhibited at the Smithsonian in late 2005.
About the front cover photography
The bright star in the upper middle of this photograph is S Mon. It is surrounded by dark dust and glowing gas. The area below and slightly to the right of S Mon is called the Fox Fur Nebula because of its color and texture. Tony Hallas took this photograph using a 14.5” f/8 RCOS Classical Cassegrain and an SBIG STL-11000 CCD camera mounted on an Astro Physics 1200 GTO mount. The exposure was 180 minutes through AstroDon H-a and RGB filters (LRGB 120:60:60:60). Copyright 2005 by Tony and Daphne Hallas.
Table of contents
Preface to the Second Edition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii
Acknowledgements to the First Edition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv
Chapter 1 Introduction — The Digital Darkroom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
The Digital Darkroom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
The Computer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Monitors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Color Calibration Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
External Drives. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Other Hardware Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Photo Printers and Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Film Scanners and Software. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Optical Storage Media and the Image Archive . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Image Management (Cataloging) Software and Image Browsers . . . . . . . . . . . . . . . . . . . . . 11
Digital Image File Formats. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Image-processing Workflow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
How to Use this Book . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
Chapter 2 The Digital Environment and Color Management . . . . . . . . . . . . . . . . . . . . . . . . . . .19
Pixels, Bits and Color Channels. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
Color Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
RGB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
CMYK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
HSB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Lab . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Grayscale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Color Spaces and Gamuts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Adobe RGB (1998). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
sRGB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Color Management. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Setting up Photoshop for Color Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Calibrating Your Monitor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Monitor Calibration Using Adobe Gamma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Printer Color Management and Softproofing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31
Setting up Photoshop for Softproofing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Calibrating other Devices. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36
Photoshop’s Assign Profile and Convert to Profile Commands . . . . . . . . . . . . . . . . . . . . . . .37
Some Final Thoughts and Tips . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38
Chapter 3 The Histogram and Levels — Defining Tonal Range . . . . . . . . . . . . . . . . . . . . . . . . . 41
The Histogram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Clipping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41
“Combed” or “Gapped” Histograms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Tonal Scale —16-bit Versus 8-bit Images . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Levels–Setting the Black and White Points of an Image. . . . . . . . . . . . . . . . . . . . . . . . . .45
Setting the Black and White Points using the Levels Sliders — Introduction to Adjustment Layers .. .48
Setting the Black and White Points “By the Numbers” using Target Values in the Image. . . . . . . . 50
Chapter 4 Adjusting Color and Local Contrast — Introduction to Masking Techniques . . . . . . . . . . . . . 57
Curves. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Using Curves to Adjust Color Balance and Contrast . . . . . . . . . . . . . . . . . . . . . . . . . 61
Applying Curves to a Selection — Introduction to Masking and Layer Masking. . . . . . . . . . . . . 67
Other Tools for Adjusting Color . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
The Color Balance Command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
The Selective Color Command and Color Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
The Replace Color Command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
The Channel Mixer Command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
The Hue/Saturation Command. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
Chapter 5 Stacking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .79
Methods for Combining Stacked Images. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
Aligning and Stacking Images Using Photoshop. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
Averaging Images Using the Layer Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
Adding Images Using the Apply Image and Calculations Commands — Measuring
Signal-to-Noise Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .89
Some Final Thoughts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
Chapter 6 Anti-Vignetting — Balancing Uneven Illumination . . . . . . . . . . . . . . . . . . . . . . . . . 99
The Subtraction Method — Introduction to Cloning. . . . . . . . . . . . . . . . . . . . . . . . . . . .100
A/V Layer Mask Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
Multiply Layers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .103
The Difference Layer A/V Mask . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .104
The Screen Layer A/V Mask . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .106
The Synthetic A/V Layer Mask . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
Selective Color Correction using a Synthetic A/V Layer Mask . . . . . . . . . . . . . . . . . . . . . .117
Some Final Thoughts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .120
Chapter 7 Additional Noise Reduction Techniques. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
Dust and Scratch Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
The Dust and Scratches Layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124
Using Photoshop’s Median Filter for Noise Reduction . . . . . . . . . . . . . . . . . . . . . . . . . .127
Using the Edit/Fade Command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .128
Removing Stray Colored Pixels Using the Color Range Command . . . . . . . . . . . . . . . . . . . . . .129
Reducing Background Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .132
Photoshop Grain Reduction Technique . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .132
A Quick Grain Reduction Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136
Reducing Green Background Noise. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137
Chapter 8 Star Techniques . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .141
Fixing Elongated Stars (“Star Shaping”) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .141
Fixing Elongated Stars — The Basics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .141
Fixing Elongated Stars with Selective Shaping . . . . . . . . . . . . . . . . . . . . . . . . . . . . .144
Isolating an Image Area for Editing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .145
Selective Star Shaping Using Layer Masks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146
Star “Shrinking” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149
Selective Star Shrinking Using Photoshop’s Minimum Filter . . . . . . . . . . . . . . . . . . . . .150
Star Shrinking to Reduce Blue/Violet Fringing . . . . . . . . . . . . . . . . . . . . . . . . . . .151
Star “Softening” — Restoring and Enhancing Colored Star Halos . . . . . . . . . . . . . . . . . . . . .152
Selective Star Softening using Curves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .154
Enhancing Star Halos . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155
Chapter 9 LRGB and Channel Mixing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161
LRGB (“Luminance Layering”). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161
LRGB — Photoshop Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161
LLRGB (“Multiple Luminance Layering”) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .166
LLRGB — Photoshop Procedure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166
Synthetic LRGB (“Synthetic Luminance Layering”) . . . . . . . . . . . . . . . . . . . . . . . . . . . .169
Synthetic LRGB — Photoshop Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169
Channel Mixing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173
Color to Monochrome Conversions Using Photoshop’s Channel Mixer. . . . . . . . . . . . . . . . . . 173
Channel Mixer — Photoshop Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .173
Synthetic Color Channels — R(G)B Photoshop Example. . . . . . . . . . . . . . . . . . . . . . . . .175
Correcting for Prismatic Dispersion and Misaligned Color Channels . . . . . . . . . . . . . . . . .176
Re-aligning Color Channels — Photoshop Procedure . . . . . . . . . . . . . . . . . . . . . . . . . 176
Chapter 10 Composites and Mosaics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .179
Creating a Composite using Layer Masks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179
Creating a Composite using the Layer Style “Blend-If” Sliders . . . . . . . . . . . . . . . . . . . . .185
Color Channel Composites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190
Creating a Mosaic. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192
Chapter 11 Sizing Images for Printing and Web Display. . . . . . . . . . . . . . . . . . . . . . . . . . . 203
PPI, DPI, Size and Resolution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .204
Size and Resolution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .204
Computer Monitor Resolution, including digital projectors . . . . . . . . . . . . . . . . . . . . .204
Output Resolution (typically print output) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205
Resizing, Resampling and Interpolation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206
Resizing — Photoshop Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .206
Resampling — Photoshop Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .208
Resizing and Resampling: More Photoshop Examples . . . . . . . . . . . . . . . . . . . . . . . . . 211
Additional Methods of Resampling Images for Printing . . . . . . . . . . . . . . . . . . . . . . . 216
Stair Interpolation (“SI”) — Photoshop Example . . . . . . . . . . . . . . . . . . . . . . . . . . 219
Sizing Images for the Web and Computer Monitor Display . . . . . . . . . . . . . . . . . . . . . . . . 222
Sizing an Image for Web Display — Photoshop Example . . . . . . . . . . . . . . . . . . . . . . . .228
Photoshop CS and CS2 — Additional Resampling Options . . . . . . . . . . . . . . . . . . . . . . . . . 230
Chapter 12 Sharpening and Unsharp Masking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .237
“One-Pass” Unsharp Masking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238
Selective Sharpening using Layer Style Blending Options . . . . . . . . . . . . . . . . . . . . . . . .240
Sharpening Guidelines and Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243
Layer-Based Selective Sharpening Using Layer Masks . . . . . . . . . . . . . . . . . . . . . . . . . . 245
Sequential, or “Multi-Pass” Sharpening using Photoshop Actions . . . . . . . . . . . . . . . . . . . . 248
Separating Dark and Light Sharpening Halos . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250
Sharpening with the High-Pass Filter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .254
“Wide Radius-Low Amount” Sharpening . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .255
Edge Masking. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .257
Difference Masking — Working with Layer Sets (Layer Groups) . . . . . . . . . . . . . . . . . . . . . .260
Chapter 13 Working with CS2, 3 and 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 265
The Digital Darkroom (Chapter 1). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .265
Monitors and Color Calibration Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267
Photo Printers and Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267
Scanners and Scanning Software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 268
Image Archiving and Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 268
The Digital Environment and Color Management (Chapter 2) . . . . . . . . . . . . . . . . . . . . . . . 268
Printer Color Management and Softproofing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 270
Calibrating Other Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .271
Adjusting Color and Local Contrast (Chapter 4) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 272
Curves. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .272
Masking and Layer Masking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .273
Other Tools for Adjusting Color . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .274
Stacking (Chapter 5). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .275
Anti-Vignetting — Balancing Uneven Illumination (Chapter 6). . . . . . . . . . . . . . . . . . . . . . 275
Additional Noise Reduction Techniques (Chapter 7) . . . . . . . . . . . . . . . . . . . . . . . . . . .275
Star Techniques (Chapter 8). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 277
LRGB and Channel Mixing (Chapter 9) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .278
Composites and Mosaics (Chapter 10). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 279
Sizing Images for Printing and Web Display (Chapter 11) . . . . . . . . . . . . . . . . . . . . . . . .279
Sharpening and Unsharp Masking (Chapter 12) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .284
Appendix A A Color Management Primer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .289
Color Space . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .289
Device Color Space . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 289
Color Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 289
RGB Color Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .290
Abstract Color Spaces in the RGB Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 291
CMYK Color Model for Output Devices. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293
Setting Up and Using a Color Management Environment. . . . . . . . . . . . . . . . . . . . . . . . . . 294
Assigning profiles in Photoshop. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295
Photoshop’s Default Color Management Settings . . . . . . . . . . . . . . . . . . . . . . . . . . .297
Managing Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .299
Appendix B — Suppliers and Other Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305
Index. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 307
