© 2005 Tim Vitale

Why Bother?
1
• Digital sensors are replacing film as the light capturing medium in photography

Why Bother?
2
• Digital sensors are replacing film as the light capturing medium in photography
• Its in your best interest to take full advantage of this new medium

Why Bother?
3
• Digital sensors are replacing film as the light capturing medium in photography
• Its in your best interest to take full advantage of the new medium
• Digital vs Film
– Linear Response
– Low Noise
– High Dynamic Range
– Large Color Depth
– Only One Lens Needed from image to print
• one lens is needed to capture light
• no lens is needed to manipulate tonal range, colors, contrast
• or even to print
• the lens will degrade image resolution by 15-40%, and lens chromatic aberrations can degrade the color, especially away from the center

Film: Non-Linear Response

Digital: Linear Response

Signal to Noise Ratio: SNR
Film SNR: 10:1
Digital SNR: 100:1
SNR 880:1
SNR 6:1
1300
400
SNR 130:1
100
60
530,000 Signal
600 Noise
0.01 0.1 1 10 100 1000
Original from : Y. Ide et al: A Three CCD HDTV Color Camera, SMPTE J, July 1990 pp.532-537 in Luther & Ingalis,Video Engineering, 3rd,1999, p.229
.

Dynamic Range & Color Depth
– Dynamic Range (RAW Gamma 1.0 at capture)
•
Film
• Digital 8-bit
•
Digital 12-bit
•
Digital 14-bit
• Digital 16-bit
– Color Depth
7-8 f-stops
5 f-stops
9 f-stops
11 f-stops
13 f-stops
2.1-2.4 D
1.5 D
2.7 D
3.3 D
3.9 D
•
Film 10-80
• Digital 8-bit 256
•
Digital 10-bit 1024
• Digital 12-bit 4096
•
Digital 14-bit 16384
• Digital 16-bit 65536
•
Digital 24-bit 16.7 M
•
Digital 36-bit 68.7 B
• Digital 42-bit
•
Digital 48-bit
4.4 T
281 T
Colors 10 um 2
B&W
B&W
B&W
B&W
B&W
Color
Color
Color
Color
4-12um 2
4-12um 2
4-12um 2
4-12um 2
4-12um 2
4-12um 2
4-12um 2
4-12um 2
4-12um 2

Why Bother?
4
• Digital sensors are replacing film as the light capturing medium in photography
• Its in your best interest to take full advantage of the new medium
• Digital vs Film
– Linear Response
– Low Noise
– High Dynamic Range
– Large Color Gamut
– Only One Lens Needed from image to print
• one lens is needed to capture light
• no lens is needed to manipulate tonal range, colors, contrast
• or even to print
• the lens will degrade image resolution by 15-40%, and lens chromatic aberrations can degrade the color, especially away from the center of the frame

Why Bother?
5
• Digital sensors are replacing film as the light capturing medium in photography
• Its in your best interest to take full advantage of the new medium
• Digital vs Film
• One person can do all imaging and printing operations
– color film requires up to 3-4 skilled operators to perform all the manipulations open to the digital photographer

Why Bother?
6
• Digital sensors are replacing film as the light capturing medium in photography
• Its in your best interest to take full advantage of the new medium
• Digital vs Film
• One person can do all operations
• After following the processes detailed next,
– a color measurement (EyeOne) made from the original artifact
– will closely match the Photoshop RGB and Lab color data in the TIFF image file
• but not necessarily the colors on the screen
• or printed colors

OK There is one Problem
1
• reds desaturate
• yellows desaturate

Color Problem
1
475nm 545nm 615nm

Color Problem
2
430 550 625

Common Solution
• Use an Input Profile
• Input Profiles are not recommended
• Input Profiles cure the 2 problems…
» reds desaturate
» yellows desaturate
– the color dyes over the sensor
– extended red sensitivity of the sensors
• …But… introduce 4 additional color problems (more later)

Color Problem: First Pass Solution
• Use >Image >Adjust >Color Balance
• > Cyan / Red >Midtones (only)
• +6
• > Yellow / Blue >Midtones (only)
• -12

TIFF File Facts
• T agged I mage F ile F ormat for bitmap graphics
• Integrity of image data depends on software
– Adobe Photoshop
– Adobe Elements
• TIFF is file wrapper, not a specification
– Header
• metadata, if any
• image generation software name, if any
– Body
• Holds 8, 10, 12, 14 and 16 bit color or grayscale bitmap data
– Footer
• ICC/ICM profile can be included with image data (5 MB)

TIFF
Possible File Types:
Uncompressed TIFF pixels
JPEG
JPEG compression blocks

How to Get the Most from a TIFF Image
2
• Use Target in the image, or image series
– GretagMacbeth ColorChecker (reflective)
– Kodak 1A B&W step wedge (transmission)
• 11 step 3.05 Dmax
– Stouffer Transmission Step Wedges
• 21 step to 3.05 Dmax
• 41 step to 4.10 Dmax

GretagMacbeth Color Checker
Full Size: 8.5” x 11” $70
Mini: 3” x 4” $60
24 Patches
6 Neutral Gray

Kodak 1A Step Wedge
B&W Negative Target
11 steps -- 0.05 to 3.05 D

Stouffer Transmission Step Wedges
About $45 calibrated, on Technical Pan film

Don’t use Kodak Q13 or Q14
• Grays are not always neutral
• Each grayscale card has different values

Don’t Use IT8.7 Type Targets
Grays are not
Neutral
Data can vary by 5% (1-13 RGB)

How to Get the Most from a TIFF Image
3
• Save Capture in Unaltered State
– Working Space Profile?
• BetterLight does now recommend embedding a Working
Space profile in their raw capture file
• Camera Raw files have an embedded Working Space
– Scanner Images are made with a Monitor Gamma correction set by the user
• Gamma 2.2 is preferred
• Gamma 1.8 was preferred by Mac users 5-10 years ago
• Name the file with “v00” (or some consistent method)
– Do not use TIFF’s LZW compression unless space requirements demand its use, lossless compression will alter the file somewhat

How to Get the Most from a TIFF Image
4
• Save Capture in Unaltered State
– Working Space Profile?
• BetterLight does not recommend embedding a profile in their raw capture version
• Camera Raw files have an embedded Working Space
– Scanner Images are made with a Monitor Gamma correction set by the user
• Gamma 2.2 is preferred
• Gamma 1.8 was preferred by Mac users 5-10 years ago
• Name the file with “v00” (or some consistent method)

How to Get the Most from a TIFF Image
5
• Set gray patches to the pre-determined
RGB values
– ColorChecker
– Kodak 1A Step Wedge
– Stouffer Transmission Step Wedge

Set RGB value in Grayscale using Photoshop >Curves>RGB
1
D R G B
0.05 242, 241, 238
0.23 201
0.44 161
0.70 122
1.05 85
1.50 53

Set RGB value in Grayscale using Photoshop >Curves>
D
2
D R G B
0.05 242, 241, 238
0.23 201
0.44 161
0.70 122
1.05 85
1.50 53

Set RGB value in Grayscale using Photoshop >Curves>
D
3
D R G B
0.05 242, 241, 238
0.23 201
0.44 161
0.70 122
1.05 85
1.50 53

Set RGB value in Grayscale using Photoshop >Curves>
D
4
D R G B
0.05 242, 241, 238
0.23 201
0.44 161
0.70 122
1.05 85
1.50 53

Set RGB value in Grayscale using Photoshop >Curves>
D
5
D R G B
0.05 242, 241, 238
0.23 201
0.44 161
0.70 122
1.05 85
1.50 53

Set RGB value in Grayscale using Photoshop >Curves>
D
6
D R G B
0.05 242, 241, 238
0.23 201
0.44 161
0.70 122
1.05 85
1.50 53

Set RGB value in Grayscale using Photoshop >Curves>
7
D R G B
0.05 242, 241, 238
0.23 201
0.44 161
0.70 122
1.05 85
1.50 53

Set RGB value in Grayscale using Photoshop >Curves>
8
D R G B
0.05 242, 241, 238
0.23 201
0.44 161
0.70 122
1.05 85
1.50 53

Set RGB value in Grayscale using Photoshop >Curves>
9
D R G B
0.05 242, 241, 238
0.23 201
0.44 161
0.70 122
1.05 85
1.50 53

Set RGB value in Kodak 1A grayscale using Photoshop >Curves>
10
D R,G&B
0.05 243
0.35 175
0.65 129
0.95 94
1.25 69
1.85 37
2.15 27
2.50 19
2.80 14
3.05 10

How to Get the Most from a TIFF Image
6
• Save Image with Tone Corrections ONLY
– v00 Uncorrected
– v0 Tone Corrected
– v1 Unsharpened Mask (USM) “Sharpen”
• if required
• not always required

Capture Devices
• Flatbed Scanner
• DSLR type Camera
• 4 x 5 view camera scanning back

How to Get the Most from a TIFF Image
7
• Capture Device: Turn off all Automatic functions
– Auto Sharpening OFF
– Auto Color Correction OFF
– Auto Tone Adjustment OFF

Turn Off Auto Functions:

Turn Off Auto Functions:

Turn Off Auto Functions:

Turn Off Auto Functions:

Turn Off Auto Functions:

Turn Off Auto Functions:

Turn Off Auto Functions:

Turn Off Auto Functions:

Turn Off Auto Functions:
PCR
Photoshop Camera Raw Plug-in

Turn Off Auto Functions:
PCR
Photoshop Camera Raw Plug-in

How to Get the Most from a TIFF Image
8
• Capture Device: Set Color Management & Gamma
– Set Working Space : <Adobe RGB 1998>
– Do Not use the <sRGB> Working Space
• the standard in many DSLRs
– Do not use an Input Profile (ICC or ICM)
•
Input Profiles cure 2 problems
» reds desaturate
» yellows desaturate
• Profiles introduce 4 types of color errors - due to the nonuniform Lab color space
» some reds go orange
» some blues go purple
» yellows desaturate
» greens desaturate
– Set Gamma
• Gamma 2.2 preferred

Color Working Space Profile
1
Adobe RGB 1998
G 2.2 D 65 sRGB
G 2.2 D 65
Ultrachrome on Premium Luster
Printer Profile

Color Working Space Profile
2
Adobe RGB 1998
Adobe RGB 1998
G 2.2 D 65 sRGB
Pro Photo
Ultrachrome on Premium Luster
Printer Profile
Ultrachrome on Premium Luster
Printer Profile

Set Color Management & Gamma:

Set Color Management & Gamma:

Set Color Management & Gamma:

Set Color Management & Gamma:

Set Color Management & Gamma:

Set Color Management & Gamma:

How to Get the Most from a TIFF Image
9
• Capture Device: Set Color Management & Gamma
– Set Gamma
• Gamma 2.2 preferred
• Gamma 1.8 was preferred by Mac users 5-10 years ago

Set Color Management & Gamma: G 2.2

Set Color Management & Gamma:
PCR
Photoshop Camera Raw Plug-in

How to Get the Most from a TIFF Image
10
• Printing Alters the Image Colors from Captured values
– Profile must be used to keep grays neutral when printing
• Compresses tonal range to capabilities of inkset
• Limits colors to capabilities of inkset and paper combination
• Translates the RGB colors to PCS space, for the above changes
– RGB > XYZ > Lab (RGB->Lab, A2B subroutine inside profile)
– Lab is a non-uniform color space that shifts colors
– introducing 4 types of color errors
» some reds go orange
» some blues go purple
» yellows desaturate
» greens desaturate
– The RGB values are temporarily altered in the file for printing
• The value of a TIFF is the numbers within the TIFF file on your hard drive, not the screen or printed versions

How to Get the Most from a TIFF Image
10
• Printing Alters the Image Colors from Captured values
– Profile must be used to keep grays neutral when printing
• Compresses tonal range to capabilities of inkset
• Limits colors to capabilities of inkset and paper combination
• Translates the RGB colors to PCS space, for the above changes
– RGB > XYZ > Lab (RGB->Lab, A2B subroutine inside profile)
– Lab is a non-uniform color space that shifts colors
– introducing 4 types of color errors
» some reds go orange
» some blues go purple
» yellows desaturate
» greens desaturate
– The RGB values are temporarily altered in the file for printing
• The value of a TIFF is the numbers within the TIFF file on your hard drive, not the screen or printed versions

tjvitale@ix.netcom.com
Information Resources
Mick Collette, BetterLight, San Carlos, CA
Robin Myers, Robin Myers Imaging, Pleasanton, CA
Bruce Lindbloom http://brucelindbloom.com
Rob Simpson, Epson America, Field Engineer,
Mission Viejo, CA
Readers and Reviewers
Jeffrey Warda, Fine Arts Museum of San Francisco
Pam Skiles, Oakland Museum Conservation Center

tjvitale@ix.netcom.com
Emeryville, California