introduction to colour management dohm digitisation of heritage materials
TRANSCRIPT
Introduction toColour Management
DOHMDigitisation of Heritage Materials
The same image displayed on three different, uncalibrated systems
Colour is always device dependent!!!
Human Vision - Colour
http://www.purveslab.net/main/
Dot colour 1 Dot colour 2SAME COLOUR!!!
Human Vision - Brightness
Grey and White
http://www.purveslab.net/main/
SAME SHADE OF GREY!!!
Human Vision - Contrast
http://www.purveslab.net/main/
THE SQUARES ARE GREY!!!
Concept of White Light
White light is composed of all visible colours
White light Prism
White light components
Human Eye Spectral Sensitivity
There are three types of colour sensitivephoto-receptors (cones) in the human eye.
They are mostly sensitive to blue, green and red spectrum of light.
Light sources
RGB - Red, Green, Blue
Computer Monitors Magnified
LCD monitor
CRT monitor1 pixel
Colour perception by the eye
CMYKCyan, Magenta, Yellow, blacK
CMYK print
Colour spaces and gamut
GAMUT - range of coloursthat a colour system candisplay, capture or print
ICC profilesHow they work
Monitor
Original Image
STANDARDCOLOUR
SPACE
Printer
Profile attached to image
Profiles used to correct output
colours(colours convertedfrom capture device colours into the “special” universal
standard space colours)
(colours convertedfrom the “special”
universal standard space into output device colour space)
ICC colour profile - information about how digital devices subjectively “see” colours
Colour Management basics
• Calibrate monitor
• Calibrate input devices (scanners & cameras if applicable)
• Calibrate output devices (printers)
Professional colour calibration
Special software and hardware is used to calibrate devices and ensure correct colour
Practical Colour Management
• Calibrate the monitor using an appropriate device(eg. Spyder Express, GretagMacbeth). Follow the prescribed procedure carefully.
• Check in computer’s “DISPLAY PROPERTIES > ADVANCED > COLOR MANAGEMENT” that the created profile has been installed and is selected as default. If not, install it manually.
• When you view images or want to print them out, make sure that you open them in software that uses ICC colour management (eg. Adobe Photoshop, Photoshop Elements, FastStone) , and colour management is switched on.
Benefits of system calibration
• Consistent colour - print matches the original
• Reduced time to obtain good colour results
• Images look the same on different computer systems and monitors
• Much better chance of reproducing accurate colours in the future (better archival properties)
QPCard 201http://www.qpcard.se
How to use it?Go to http://www.qpcard.se and watch the instructional video
Colour links
• International Color Consortium (ICC) – www.color.org
• ColorVision - http://www.colorvision.com/learn_colormanagement1.php
• Microsoft - http://www.microsoft.com/whdc/device/display/color/default.mspx
Andrew Stawowczyk Long email: [email protected] .au
Phone: +61 408 478 522 Skype: andrewstawowczyklong