Introduction to Colour Management DOHM Digitisation of Heritage

Introduction to Colour Management DOHM Digitisation of Heritage Materials

The same image displayed on three different, uncalibrated systems Colour is always device dependent!!!

Human Vision - Colour SAME COLOUR!!! Dot colour 1 Dot colour 2 http: //www. purveslab. net/main/

Human Vision - Brightness Grey and White SAME SHADE OF GREY!!! http: //www. purveslab. net/main/

Human Vision - Contrast THE SQUARES ARE GREY!!! http: //www. purveslab. net/main/

Concept of White Light White light is composed of all visible colours White light components White light Prism

Human Eye Spectral Sensitivity There are three types of colour sensitive photo-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 1 pixel CRT monitor Colour perception by the eye

CMYK Cyan, Magenta, Yellow, blac. K

CMYK print

Colour spaces and gamut GAMUT - range of colours that a colour system can display, capture or print

ICC profiles How they work (colours converted from the “special” universal standard space into output device colour space) Profile attached to image Original Image (colours converted from capture device colours into the “special” universal standard space colours) STANDARD COLOUR SPACE ICC colour profile - information about how digital devices subjectively “see” colours Profiles used to correct output colours Monitor Printer

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, Gretag. Macbeth). 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, Fast. Stone) , 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 201 http: //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 • Color. Vision http: //www. colorvision. com/learn_colormanage ment 1. 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