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Color Management

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  • 1. Introduction to Color Management Part 1 Photographers of Vashon February 28, 2008
  • 2. Purposes of Presentation
    • Educate POV members about current digital practices and their benefits
    • Begin building a shared vocabulary of standards within POV
    • Increase the technical quality of our artwork for forthcoming exhibitions and personal applications
    • Enable POV to further educate community members
  • 3. Learning Objectives
    • By the end of this presentation you will have
    • a greater understanding of:
    • The benefits of using a color-managed workflow for processing digital images
    • Computer-based digital devices and their corresponding profiles
    • Key terms and their definitions
    • Standard color management tools
  • 4. Organization of Presentation
    • This presentation covers a lot of material--both definitions and practical applications of color management.
    • Practices that will provide immediate benefit to your digital processing workflow are highlighted by “High Priority” checkmarks
    1
  • 5. What Is A Digital Workflow?
    • Workflow is a term used to describe the sequence of activities, people, data, and tools required to produce a desired output in digital photography.
    • >Workflow focuses on process rather than documents.
  • 6.  
  • 7. What Is Color Management?
    • Color management encompasses a set of software technologies that seeks to match color across input, display, and output devices by referencing their color behavior to a known standard by means of device profiles.
  • 8. Why Color Management? (1)
    • Color management
    • Helps ensure consistency among all these devices
    • Minimizes the perceived differences in displayed colors between devices
    Obtaining predictable color reproduction in the digital darkroom can be a challenge because each device--digital camera, scanner , monitor, or printer--responds to or produces color differently.
  • 9.  
  • 10. Why Color Management? (2)
    • A color-managed workflow can help you. . .
    •  Improve the color match between your monitor and printer.
    •  Achieve satisfying results with fine art papers or nonstandard inks, for example, from independent manufacturers.
    •  Send out an image to be printed accurately on a large format printer at a service bureau or Costco.
    •  Reproduce color as precisely as possible-- for example, for fashion, weddings, or art reproduction.
  • 11. Color Management Foundation
    • Two key elements of color management:
    •  ICC profiles : data that define color in devices (digital cameras, printers, scanners, monitors) or image color spaces (sRGB, Adobe RGB 1998, ProPhoto RGB).
    • Gamut mapping: the ability of color information to be transferred from one device (or color space) to another.
      • From an image on a memory card to a monitor
      • From Adobe RGB to sRGB color spaces
  • 12. Definitions (1)
    • ICC (International Color Consortium): Hardware and software vendors dedicated to developing cross-platform standards for color communication and consistency.
    • Color space : A three-dimensional representation of the colors that can be produced by a color model.
    • Gamut : The range of color a device can produce.
    sRGB vs. Adobe RGB color space
  • 13. Profiles vs. Color Spaces
    • Profiles are for devices
    • Color spaces are for images
  • 14. Color-Managed Workflow Strategy
    • Use ICC-aware tools to recognize color spaces and device profiles, and apply gamut mapping when moving images among the devices!
  • 15. The Difficult Parts
    • Learning a new language
    • Learning new tools
    • Obtaining or creating profiles
    • Evaluating quality
    • Setting up smart workflows
    • Documenting your workflow
    • Balancing your artistic good sense with what the computer shows you
  • 16. Mac vs. Windows Differences
    • ICC standards based on ColorSync
    • All Mac applications(Word/Photoshop/Mail) reflect consistent color management
    • Windows XP - Image Color Management (ICM) http://www.microsoft.com/windowsxp/using/digitalphotography/prophoto/colorcontrol.mspx
    • Color monitor calibration tools work fine in XP
    • Not all Windows applications show consistent color in XP
    • Vista fixes this: http://www.microsoft.com/prophoto/articles/colormgmt.aspx
    • Both OS’s equally capable with color management
    • Apple pioneered ColorSync color management system that is built into Mac OS-X
  • 17. Start with the monitor
    • A calibrated monitor is your stake in the ground.
    • Calibration adjusts the monitor to a specific color temperature, gamma, and black & white luminance.
    • Calibration produces a display profile.
    • The calibration software works with your computer’s operating system to default to the same display profile every time you use your computer.
    1
  • 18. Definitions (2)
    • Color temperature : A measurement of the color of white light, expressed in Kelvins . Computer monitors typically have a color temperature of 5000-9300K: 5000K= yellowish-white, 9300K=blue white. 6500K is recommended
    • Gamma : describes the reflectance of your prints . Gamma affects middle tones; it has no effect on black or white. Too high gamma = too dark middle tones appear. Too low gamma = too light middle tones. 2.2 is standard gamma for displays today.
    • Black & white luminance : the amount of light or dark of a defined area
  • 19. Display Calibration Benefits
    • Enables Photoshop color consistency
    • Prerequisite for printer accuracy
    • Improves the look of everything on your computer
    • Tones down too-bright LCD mfgr. presets
  • 20. Display Calibration Issues
    • Don’t confuse display profile with color space
      • Often software will display one long confusing list of all profiles and color spaces
      • Name your display profile for yourself
    • CRTs burn out after 6 years
    • Calibrate in near dimly lighted room
      • Indirect lighting will help accuracy
    • http://www.gballard.net/boutique/colorcorrecting.html
  • 21. Display Calibration Methods
    • Estimating with system software
      • Mac ColorSync display utility
      • Adobe Gamma for Windows
      • in Photoshop
    • Specific software-only calibration
      • Supercal is OK
    • Hardware device with matching software
      • Spyder, Monaco, XRite etc. colorimeter pucks hang off displays, take measurements and create custom profile. $200-500
      • Dedicated software works with pucks; all are good.
      • Color Eyes Display works with multiple pucks, is superior software, and is expensive.
    • Colorimeters also used for calibrating HDTVs
    Less effective More effective
  • 22. You Must Use Printer Profiles
    • Accurate monitor + printer profiles = prints that closely match what you see on your monitor.
    • Without profiles, you need to rely on trial and error, guessing, and luck.
    • Printer profiles are easy to obtain and use.
    • Most of you use them in Photoshop now.
    2
  • 23. Photoshop Print With Preview Options Image color space Rendering Intent Printer profile Sets CS2 to manage color
  • 24. Definitions (3)
    • Rendering intent : methods and rules for converting colors from one color space to another.
    • The four ICC specified rendering intents are discussed on next slide.
    • Out-of-gamut colors : colors present in the source color space that the destination color space or profile cannot reproduce.
    • Example: A deep green in the image file that a printer cannot reproduce precisely.
  • 25. Definitions (4)
    • White Balance : a reference point which represents white that is required by digital cameras. All other colors are then calculated based on the white point.
    • Hue : a dimension of color we readily experience when we look at color. How well individual colors can be distinguished in an image.
    • Saturation : the dominance of hue in the color. Desaturated colors become more gray.
    • Lightness : Also known as value , how light or dark a color is--its intensity.
    • A nice reference:
    • http://www.ncsu.edu/scivis/lessons/colormodels/color_models2.html#hue.
  • 26. Relative Colorimetric Rendering
    • Relative Colorimetric --produces superior results generally.
    • How it works : first scales the white of the source space to the white of the target space, adjusting all other colors relative to that white. Then it matches the adjusted colors in the source space that are inside the gamut of the target space exactly, and clips out-of-gamut colors to the nearest reproducible hue, sacrificing lightness and saturation.
  • 27. Perceptual Rendering
    • Perceptual – good for images with significant shadow details where a slight lightening of the print is acceptable to open up the shadows. Also images with areas of highly saturated color can benefit from Perceptual rendering. If you see color banding in the soft proof with relative colorimetric selected, try perceptual.
    • How it works: attempts to compress the gamut of the source space into the gamut of the destination space -- even though all the colors may change in the process.
  • 28. Absolute Colorimetric Rendering
    • Absolute Colorimetric-- used to simulate an output on your monitor or on your proofing system (soft proofing). Useful for visualizing what a printing service will produce.
    • How it works: scales the white of the destination space to the white of the source space
  • 29. Saturation Rendering
    • Saturation-- least used intent; Useful for cartoons, comics, business graphics.
    • How it works: Saturation rendering maps fully-saturated colors in the source space to fully saturated colors in the target space, sacrificing hue and lightness.
  • 30. Obtaining Printer Profiles
    • Most printer profiles come with the software drivers that you install after purchasing the printer. Also available online at the support site of the mfgr.
    • Some printer profiles are pre-installed on your computer. These appear in when you browse to add a printer.
    Get more profiles Existing profiles
  • 31. Paper Profiles Matter
    • Accurate paper profiles+printer profiles = richer prints that closely match what you see on your monitor.
    • Ink will lay on paper as intended with artful grain patterns.
    • Without profiles, you need to rely on trial and error, guessing, and luck.
    • Paper profiles are easy to obtain and use.
    • Some may be substituted for others, but it requires trial and error.
    3
  • 32. Using Installed Paper Profiles (1)
    • Paper profiles are accessed via the Print dialog box.
    • Profiles are listed in the Presets dropdown menu
      • Give profiles your own names using the Save As function
  • 33. Using Installed Paper Profiles (2)
    • Paper and ink configurations are accessed via the 3rd dropdown menu.
    • Not intuitive interface on Macs!
  • 34. Obtaining 3rd-Party Paper Profiles
    • Sometimes available from printer mfgr website
    • Paper mfgrs usually provide downloads on their websites
    • Newer printers may not yet have paper profiles
    • Some OEM profiles can be successfully substituted for branded ones
      • Ilford for Costco or Staples
  • 35. Obtaining Pro Photo Lab Profiles
    • Dry Creek Photo provides printer and paper profiles online for soft proofing for
      • All Costco stores
      • Many pro labs including Panda and Capitol Hill Photo
    • Other lab websites often callout standard profiles or will provide upon request
    • Dry Creek and others also can create custom ICC printer profiles for your own setup
    • http://www.drycreekphoto.com/icc/
  • 36. Basic Color Management in Photoshop
    • Photoshop can be completely color managed
    • Workflow starts when images are imported
    • Be consistent with use of color spaces and profiles
    • Begin with the end in mind
      • Know the delivery targets for your images
        • Paper
        • Website
        • Magazine
        • Poster
    4
  • 37. Assigning Color Space in Photoshop (1)
    • Photoshop assigns your desired color space
    • when images are imported.
    • Adobe RGB (1998) is preferred for studio inkjet printers
    • sRGB is critical for web-based images
    • Check the requirements for pro printing services
  • 38. Assigning Color Space in Photoshop (2)
    • In CS2, choose Color Settings under the Edit menu. Adobe RGB (1998) is preferred for studio inkjet printers
  • 39. Assigning Color Space in Photoshop (3)
    • For studio printing, replicate these settings in the dialog box.
    • For web delivery, change the topmost setting to North America Web/ Internet
  • 40. Color Space Mismatches in Photoshop
    • Color management mismatches can trigger profile warnings upon copy/pasting images that don’t match your desired color space.
    • The preference box lets you choose between using one of two color spaces or zero color management
  • 41. Assigning Color Space in Photoshop
    • You can also change color spaces of image files within CS2.
      • Choosing a different Profile button dropdown menu assigns the new profile to the image without converting colors to the profile space. This may dramatically change the appearance of the colors as displayed on your monitor.
    • This is useful when an image is missing its profile or has an incorrect embedded profile
    • You can also remove a profile by clicking on the Don’t Color Manage This document button.
  • 42. Converting Color Space in Photoshop
    • CS2 allows you to “Convert” the color spaces of images. This is different from “Assigning” a color space.
      • Choosing Convert to Profile changes the image’s colors to the new color space This will dramatically change the appearance of the colors as displayed on your monitor.
    • Conversion allows you to edit in one color space and then convert to another.
      • Ex. soft proofing an image to see how it will appear in a different output environment, such as a pro printing service or Costco.
  • 43. And What About Lightroom?
    • Adobe Lightroom’s default color space is ProPhoto RGB, the largest one available.
    • You can configure Lightroom to export images to sRGB or Adobe RGB color spaces.
    • Images going from Lightroom to Photoshop for more editing can be exported in any of the three color spaces.
  • 44. Color Management and the Internet
    • HP and Microsoft pioneered web colors
    • sRBG is de facto color space for web
    • Limitations
      • Browser issues; lowest common denominator viewer
      • Never embed Adobe RGB in Internet images
      • Only a few browsers (Safari, OmniWeb) are color managed
        • http://www.gballard.net/psd/go_live_page_profile/embeddedJPEGprofiles.html
      • Computer OS color management system makes an inaccurate assumption about the source file
    5
  • 45. Color Spaces and Your Camera
    • Many cameras allow setting of color spaces
    • Color space menu settings only relevant for .jpg files
      • RAW files are unaffected
      • RAW files will be set to desired color space when importing into Photoshop or Lightroom
    • You can go from Adobe RBG to sRBG, but not the other way
      • Set color space to Adobe RBG and then assign when needed
      • If you are shooting for web only, use sRGB
  • 46. Consider Calibrating Your Camera
    • Ensures more consistent color from the camera’s images in Photoshop and Lightroom
      • more accurate hue and saturation
    • Once specific calibration presets are developed, using them is a one-click process in Photoshop and Lightroom
    • This calibration is not directly related to ICC calibrated profiles.
  • 47. Definitions (5)
    • Firmware : is software that operates a hardware device and is stored on the flash memory of the device. Can be updated.
    • Ex. DSLRs have firmware upgrades to fix bugs or provide new functions.
    • CCD sensor: charge-coupled device used by many digital cameras to read the intensity of light.
    • CMOS sensor: Complementary metal–oxide– semiconductor used by many digital cameras to read the intensity of light.
  • 48. How Camera Calibration Works
    • CS2 & Lightroom use two built-in profiles for each supported model of camera when it interprets image data.
    • Profiles are produced by photographing a color target under different white-balanced lighting conditions. When you set a white balance, software uses the profiles for your camera to extrapolate color information.
    • These camera-specific profiles are generic, derived from baseline units.
    • Your camera may be different from baseline units due to design and firmware changes.
  • 49. Software Calibration Presets
    • Presets in Photoshop Adobe Camera Raw and Lightroom allow you to tweak the interpretation of color to better match the characteristics of your camera and CCD/CMOS processing chip.
    Calibration tab in CS2 ACR Calibration slider in Lightroom Lightroom user presets Profile Profile User tweaks
  • 50. Obtaining Calibration Presets
    • The purist process for properly calibrating your camera requires technical equipment and skills beyond our scope.
    • The easy way: search for “camera calibration” in online camera- specific forums such as dpreview.com or photo.net. Or post a query there.
    • Then compile the various configurations as settings or presets and determine which one works best for your camera or aesthetic.
    Calibration slider in Lightroom Lightroom user presets Profile Each preset is slightly different
  • 51. Scanner Calibration
    • Scanner profiles ensure accurate and consistent color and density captures. Scanning calibration can be done on your scanner using an industry standard reference chart called an IT8 Target.
    You scan the target and then use profile creation software to read the data and build a custom profile. After the profile is created, you then assign it to newly scanned images as they are imported into Photoshop. 6
  • 52. Scanner Calibration Tips
    • Allow your scanner to warm up before creating a profile - 20 minutes should do.
    • Handle the IT8 target carefully and keep it in a dark folder to avoid fading.
    • Different profiles need to be created for reflective scans and transparency scans.
    • Create a new profile if you change the lamp or if you have inconsistent results.
    • Keep the scanner’s glass surface clean.
    • Always check for scanner firmware and software updates
  • 53. Five Most Important CM Practices
    • Calibrate your monitor
    • Use printer & paper profiles
    • Document your workflow regularly
    • Use the right color spaces for the right job
    • Observe the art in your work
  • 54. Valuable CM Resources
    • Making fine prints in your digital darkroom, Norman Koren
      • http://www.normankoren.com/makingfineprints.html
    • Andrew Rodney’s Digital Dog
      • http://www.digitaldog.net/
    • CreativePro Books
      • http://www.creativepro.com/eservices/bookstore/
    • Cambridge in Color
      • http://www.cambridgeincolour.com/tutorials/color-management1.htm
    • Adobe CM Terminology
      • http://kb.adobe.com/selfservice/viewContent.do?externalId=320624&sliceId=2
    • Martin Evening Books
      • http://kb.adobe.com/selfservice/viewContent.do?externalId=320624&sliceId=2