Color Science and Digital Imaging - An Essential Guide for Visual Effects Artists, Filmmakers,

This book, written by a leading expert in the field of visual effects, demystifies the complex subject of color science and how it should be managed from project ideation to completion.

List of contents

Foreword...........................................................................................xv
Preface............................................................................................. xix
Acknowledgments............................................................................ xxiii
Introduction: The Five Spaces of the Digital Imaging Pipeline...........1
Chapter 1 - World Space..............................................................5
1.1 The Nature of Light....................................................................6
1.1.1 Wavelength............................................................................6
1.1.2 Amplitude..............................................................................7
1.1.3 Phase....................................................................................8
1.1.4 Polarization............................................................................8
1.1.5 Monochromatic Light.............................................................9
1.1.6 Coherent Light.......................................................................9
1.1.7 Particles............................................................................... 10
1.1.8 The Inverse Square Law...................................................... 10
1.1.9 Interior vs. Exterior Lighting.................................................. 11
1.2 Measuring Light...................................................................... 11
1.2.1 Candela (cd): The Brightness of a Light Source................... 12
1.2.2 Lumen (lm): The Total Amount of Incident Light................... 12
1.2.3 Lux (lx): How Brightly a Scene is Lit..................................... 12
1.2.4 Other Units.......................................................................... 13
1.3 Dynamic Range........................................................................ 13
1.3.1 Brightness vs. Luminance.................................................... 14
1.3.2 What is Dynamic Range?..................................................... 14
1.3.3 Stops................................................................................... 16
1.4 A Color Science Moment........................................................ 16
1.4.1 Emission Spectrums............................................................ 17
1.4.2 Spectral Reflectance............................................................ 17
1.4.3 Color Stimulus..................................................................... 18
1.5 Light Sources......................................................................... 19
1.5.1 Emission Spectrums............................................................ 19
1.5.2 Color Temperature...............................................................21
1.5.3 Standard Illuminants............................................................23
1.6 Surface Interactions with Light................................................ 24
1.6.1 Spectral Reflectance............................................................ 24
1.6.2 Diffuse vs. Specular Reflections...........................................26
1.7 Exotic Surface Interactions with Light.....................................27
1.7.1 Scattering............................................................................27
1.7.2 Polarized Light.....................................................................29
1.7.3 The Fresnel Effect................................................................30
1.7.4 Color from Interference........................................................32
1.7.5 Dichroic Filters.....................................................................33
1.8 How We See the World.........................................................33
1.8.1 Color Perception..................................................................34
1.8.2 CIE xy-chromaticity Diagram...............................................35
1.8.3 Our Visual Response...........................................................37
1.8.4 Adaptation...........................................................................38
1.8.4.1 General Brightness Adaptation.............................39
1.8.4.2 Lateral Brightness Adaptation...............................39
1.8.4.3 Chromatic Adaptation...........................................40
1.8.5 Calculating Luminance.........................................................40
1.8.6 Metamers............................................................................42
1.9 Conclusion.......................................................................................43
Chapter 2 - Camera Space....................................................................... 45
2.1 Camera Perceptions of Color...........................................................46
2.1.1 Spectral Sensitivity..............................................................46
2.1.2 Camera Gamuts..................................................................48
2.1.3 Converting Light to Digits.....................................................48
2.1.4 The Debayer Process..........................................................49
2.1.5 Camera Imaging Math......................................................... 51
2.1.6 Light Sources......................................................................52
2.1.6.1 Color Temperature................................................52
2.1.6.2 Spectral Emissions...............................................53
2.1.7 CCD vs. CMOS...................................................................54¿
2.2 Space and Time...............................................................................56
2.2.1 Resolution...........................................................................56
2.2.2 ISO......................................................................................57
2.2.3 Speed..................................................................................57
2.2.4 Sensor Crop........................................................................59
2.2.5 Sensor Size.........................................................................60
2.2.6 Anamorphic Formats...........................................................62
2.2.6.1 Cinemascope 2.39................................................62
2.2.6.2 HDTV 1.33............................................................63
2.3 Camera Dynamic Range..................................................................63
2.3.1 Clipping...............................................................................64
2.3.2 Bit Depth.............................................................................65
2.4 Video Standards..............................................................................66
2.4.1 Resolutions..........................................................................66
2.4.1.1 HDTV Standards ....................................................................66
2.4.1.2 UHDTV Standards ....................................................................67
2.4.2 Scan Modes........................................................................67
2.4.2.1 Progressive Scan..................................................67
2.4.2.2 Interlaced Scan.....................................................67
2.4.2.3 History..................................................................69
2.4.3 Frame Rates........................................................................70
2.5 Output Options................................................................................ 71
2.6 Camera Artifacts..............................................................................72
2.6.1 Noise...................................................................................72
2.6.2 Rolling Shutter..................................................................... 74
2.6.3 DSLR Rolling Shutter...........................................................75
2.6.4 Vignetting............................................................................75
2.7 Lens Artifacts...................................................................................76
2.7.1 Lens Distortion....................................................................78
2.7.2 Spherical Aberration............................................................78
2.7.3 Chromatic Aberration...........................................................79
2.7.4 Depth of Field......................................................................79
2.7.5 Veiling Glare.........................................................................80
2.7.6 Lens Flare............................................................................80
2.7.7 Bokeh..................................................................................81
2.7.8 The Swirly Bokeh.................................................................81
2.8 The DIT............................................................................................82
2.8.1 On-Set Support...................................................................82
2.8.2 Data Management...............................................................83
2.8.3 Color Grading......................................................................83
2.8.4 Post-Production Liaison.......................................................83
2.9 Virtual Production............................................................................84
2.9.1 How it Works.......................................................................84
2.9.2 The Promise........................................................................85
2.9.3 The Problems......................................................................86
2.10 What about 35 mm Film?................................................................87
2.10.1 Composition........................................................................87
2.10.2 Frame Rate..........................................................................88
2.10.3 Color Gamut........................................................................88
2.10.4 Grain....................................................................................89
2.10.5 A Softer Look......................................................................89
2.10.6 No Rolling Shutter................................................................90
2.10.7 Color Temperature...............................................................90
2.11 Conclusion.......................................................................................91
Chapter 3 - Storage Space....................................................................... 93
3.1 Image Structure...............................................................................94
3.1.1 Pixels...................................................................................94
3.1.2 Bit Depth.............................................................................95
3.1.3 Channels.............................................................................97
3.1.4 Deep Data...........................................................................98
3.1.5 Metadata...........................................................................100
3.2 Compression Strategies................................................................. 101
3.2.1 Reduced Bit Depth............................................................ 102
3.2.2 Color Subsampling............................................................ 104
3.2.2.1 Luminance and Chrominance............................. 105
3.2.2.2 Subsampling Schemes....................................... 105
3.2.3 Discrete Cosine Transform (DCT)....................................... 107
3.2.4 MPEG................................................................................ 109
3.2.4.1 Spatial Compression........................................... 109
3.2.4.2 Temporal Compression....................................... 110
3.2.4.3 Summary............................................................ 110
3.2.5 Graphics Lossless Compression........................................111
3.2.5.1 RLE Compression................................................111
3.2.5.2 LZW Compression.............................................. 112
3.3 Codecs.......................................................................................... 112
3.3.1 H.264................................................................................ 113
3.3.2 H.265.................................................................................114
3.3.3 JPEG 2000.........................................................................114¿
3.3.4 ProRes.............................................................................. 115
3.3.5 DNxHD.............................................................................. 115
3.4 Containers..................................................................................... 116
3.4.1 MOV.................................................................................. 116
3.4.2 MP4................................................................................... 116
3.4.3 AVI......................................................................................117
3.4.4 Summary............................................................................117
3.5 Log Images.....................................................................................117
3.5.1 Why Log?.......................................................................... 118
3.5.2 What is Log Data?............................................................. 120
3.5.3 Data Point Distribution....................................................... 121
3.5.4 How Log Images Are Created............................................ 122
3.5.5 Log for Photography.......................................................... 123
3.6 Cinema Export Options................................................................. 125
3.6.1 Camera RAW..................................................................... 125
3.6.2 Camera Log....................................................................... 126
3.6.3 Compressed Exports........................................................ 126
3.7 Cinema File Formats...................................................................... 127
3.7.1 EXR................................................................................... 128
3.7.2 DPX................................................................................... 129
3.7.3 ProRes.............................................................................. 129
3.7.4 DNxHR.............................................................................. 130
3.7.5 Archival.............................................................................. 130
3.8 Photography Export Options.......................................................... 131
3.8.1 Camera Raw...................................................................... 131
3.8.2 Log Recording (Camera Log)............................................. 131
3.8.3 Compressed Exports........................................................ 132
3.9 Photography File Formats.............................................................. 132
3.9.1 DNG.................................................................................. 133
3.9.2 JPEG................................................................................. 133
3.9.3 PSD................................................................................... 133
3.9.4 PNG.................................................................................. 133
3.9.5 TIFF................................................................................... 133
3.9.6 WebP................................................................................ 134
3.9.7 HEIF.................................................................................. 134
3.9.8 Do Not Use........................................................................ 134
3.10 Conclusion..................................................................................... 135
Chapter 4 - Work Space...........................................................................137
4.1 Color Theory.................................................................................. 138
4.1.1 Additive Color.................................................................... 138
4.1.2 Subtractive Color............................................................... 139
4.2 Color Models................................................................................. 140
4.2.1 RGB.................................................................................. 142
4.2.2 HSL................................................................................... 142
4.2.3 YCbCr............................................................................... 143
4.2.4 CMYK................................................................................ 144
4.3 Color Spaces................................................................................. 145
4.3.1 CIE Chromaticity Diagram.................................................. 146
4.3.2 Primary Chromaticities....................................................... 148
4.3.3 White Points...................................................................... 148
4.3.4 The Transfer Function........................................................ 149
4.3.5 Color Gamuts.................................................................... 151
4.3.6 Pointer's Gamut................................................................. 153
4.3.7 CIEXYZ and CIELAB (CIE L*a*b*)........................................ 153
4.4 Linear vs. Gamma Corrected......................................................... 155
4.4.1 What is Gamma, Exactly?.................................................. 157
4.4.2 Monitor Gamma................................................................. 159
4.4.3 Gamma Correction............................................................ 160
4.4.4 Gamma-Corrected Images................................................ 160
4.4.5 Linear Images.................................................................... 161
4.5 Integer vs. Float............................................................................. 162
4.5.1 Integer............................................................................... 163
4.5.2 Float.................................................................................. 163
4.6 LDR vs. HDR Images..................................................................... 165
4.7 Choosing Your Work Space........................................................... 166
4.7.1 Working in Linear............................................................... 167
4.7.2 Working in Display Space.................................................. 168
4.7.3 Working in ACES............................................................... 169
4.7.4 Working in Log.................................................................. 170
4.7.4.1 Picking the Right Curve....................................... 171
4.7.4.2 Going Negative................................................... 172
4.7.4.3 Limited Dynamic Range...................................... 172
4.8 Photography Work Spaces.............................................................174
4.8.1 sRGB..................................................................................174
4.8.2 Adobe RGB....................................................................... 175
4.8.3 ProPhoto RGB................................................................... 176¿
4.8.4 SWOP............................................................................... 176
4.9 Archiving........................................................................................ 178
4.9.1 OpenEXR.......................................................................... 179
4.9.2 DPX................................................................................... 179
4.9.3 Camera Raw...................................................................... 179
4.10 Conclusion..................................................................................... 179
Chapter 5 - Display Space.......................................................................181
5.1 Display Attributes........................................................................... 182
5.1.1 Spectral Emissions............................................................ 182
5.1.2 Color Gamut...................................................................... 183
5.1.3 White Point........................................................................ 184
5.1.4 Transfer Function (Gamma)................................................ 184
5.1.5 Brightness......................................................................... 184
5.1.6 Contrast Ratio................................................................... 185
5.1.7 Bit Depth........................................................................... 186
5.1.8 Frame Rates...................................................................... 187
5.1.9 Refresh Rates.................................................................... 188
5.1.10 Calibration......................................................................... 188
5.1.11 Viewing Surround.............................................................. 189
5.2 SDR vs. HDR................................................................................. 191
5.2.1 Cinema.............................................................................. 192
5.3 HDR Display Formats..................................................................... 192
5.3.1 Hybrid Log Gamma (HLG)................................................. 193
5.3.2 The Perceptual Quantizer (PQ)........................................... 193
5.4 Display Devices.............................................................................. 195
5.4.1 Flat-Panel Display Construction......................................... 195
5.4.2 Workstation Monitors......................................................... 196
5.4.2.1 Specs................................................................. 196
5.4.3 HDTV................................................................................. 197
5.4.3.1 Specs................................................................. 198
5.4.4 Digital Cinema................................................................... 198
5.4.4.1 Specs................................................................. 199
5.5 Coming Soon.................................................................................200
5.5.1 UHDTV..............................................................................200
5.5.1.1 Specs.................................................................202
5.5.2 Digital Cinema 2.0..............................................................203
5.5.2.1 RGB Lasers........................................................203
5.5.2.2 Laser Phosphor..................................................203
5.5.2.3 LED Screens.......................................................204
5.5.2.4 High Frame Rate Movies.....................................204
5.5.2.5 Specs.................................................................205
5.6 Conclusion.....................................................................................205
Chapter 6 - Color Management............................................................ 207
6.1 Color Grading................................................................................208
6.1.1 1D LUTs.............................................................................209
6.1.2 3D LUTs.............................................................................209
6.1.3 Grading Operations........................................................... 210
6.1.4 Range Controls.................................................................. 212
6.1.5 Secondary Color Grading.................................................. 213
6.1.6 Scopes.............................................................................. 215
6.1.6.1 Waveform Monitor............................................... 216
6.1.6.2 Vectorscope........................................................ 217
6.1.6.3 Histogram........................................................... 217
6.1.7 Color Grading in Log......................................................... 218
6.1.8 Using Histograms..............................................................220
6.1.8.1 Color Matching...................................................221
6.1.8.2 Increasing Contrast.............................................221
6.2 Digital Intermediate (DI)..................................................................222
6.2.1 Conforming........................................................................222
6.2.2 The Mastering Process......................................................223
6.2.3 Visual Effects..................................................................... 224
6.2.4 Deliverable File Formats.....................................................225
6.3 ICC Profiles....................................................................................226
6.3.1 How ICC Profiles Work......................................................227
6.3.2 Color Space Conversions..................................................229
6.3.3 Gamut Mapping................................................................229
6.4 Working with Supersized Gamuts.................................................. 231
6.4.1 Viewing Supersized Gamuts.............................................. 231
6.4.2 Remapping Supersized Gamuts........................................232
6.4.2.1 Large to Small Gamuts.......................................232
6.4.2.2 Small to Large Gamuts.......................................233
6.4.3 Tone Mapping.............................................

About the author

Steve Wright, an award-winning VFX pioneer and renowned educator, is the published author of two popular books: Digital Compositing for Film and Video and Compositing Visual Effects. In 2005, his attention turned full-time to educating the next generation of VFX practitioners, imparting his vast technical knowledge gleaned from 30-plus years of production experience. His love of digital imaging technology and color science is the mainstay of his training website, FX Ecademy.

Summary

This book, written by a leading expert in the field of visual effects, demystifies the complex subject of color science and how it should be managed from project ideation to completion.

Product details

• Authors: Steve Wright
• Publisher: Taylor & Francis Ltd.
• Languages: English
• Product format: Paperback / Softback
• Released: 21.11.2024
• EAN: 9781032773865
• ISBN: 978-1-0-3277386-5
• No. of pages: 278
• Subjects: Humanities, art, music > Art > General, dictionaries; PERFORMING ARTS / Film / Direction & Production, Film production: technical & background skills, Filmmaking and production: technical and background skills