html5-img
1 / 13

Colours and Computer

Colours and Computer. Jimmy Lam The Hong Kong Polytechnic University. Agenda. How colour is displayed on computer? How colour is displayed on printer or textile fabric? 8 colour modes Colour terms and definition Colour simplified Discussion. Colour Display on Computer.

lyris
Download Presentation

Colours and Computer

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Colours and Computer Jimmy Lam The Hong Kong Polytechnic University

  2. Agenda • How colour is displayed on computer? • How colour is displayed on printer or textile fabric? • 8 colour modes • Colour terms and definition • Colour simplified • Discussion

  3. Colour Display on Computer • Display of colour on computer monitor is based on R,G, B (additive colour) • Colour output on colour printer or textile printer is based on C,Y,M, K (subtractive colour). • The two colour modes (addition or subtraction), however, are not the same. • Therefore, the display colour on the monitor is not the same as colour output on printer.

  4. Colour modes on computer display (1) • Bitmap – pixels are 100% B/W • Grayscale – pixels are B/ W or up to 255 shades of gray • Duotone – printing method using 2 or more plates to add depth to grayscale • Indexed colour – colour table up to 256 colours

  5. Color mode on computer display (2) • RGB – most widely used • CMYK – Cyan, magenta, yellow, black (K value) • Lab colour – 3-channel mode that can be know for true colour • Multichannel – 256 multi-level grayscale channels

  6. Color display on computer • The two most common modes used by computer display (monitor) and computer output (printer) are • RGB mode and • CYMK mode

  7. Matching RGB with CYMK What You See Is What You Get • Colour gamut: refers to imaging devices, e.g. scanners, monitors, printers – device to display a subset of all visible colours • Colour mapping: permits the best match in appearance to the source image

  8. Colour Definition(1) • Typically defined as the presence or absence of light reflected/ not reflected from a surface • Colour is defined by Hue, Value and Saturation in the Industry

  9. Colour Definition (2) :Hue • Primary hues – Red, Yellow, Blue • Secondary hues – Green, Orange, Violet • Tertiary hues - yellow-green, red-violet, etc.

  10. Colour Definition (3) Value • Value is concerned with the light and dark properties of color. • Value – range of grays from white to black • Closest to white – tints • Closest to black - shades

  11. Colour Definition (4) • All hues can be made in all values. • Adding white paint will make any pigment lighter. • Adding black paint will make most pigments darker • Value can exist without hue e.g. Black, white and gray

  12. Web safe colour palette Colour can be displayed “correctly” in both computer monitor and colour printer

  13. Questions • Why colour cannot display correctly on both computer screen and colour printer? • How these problems can be addressed today?

More Related