Introduction to Colour Management DOHM Digitisation of Heritage Materials.

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: info@dohm.com .au

Phone: +61 408 478 522 Skype: andrewstawowczyklong