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Colour

Submitted by Peter on Tue, 2010-06-08 07:39

Our eyes can detect 12 million colours. HTML can display 16 million colours. CRT based monitors easily display the 16 million HTML colours while LCD monitors struggle to keep up. If you want perfect colour display, keep your CRT monitor for a while or spend more than you expect for an LCD screen.

This is an article from 2004 updated several times.

Color

Color is the American spelling of colour. HTML adopted the American spelling. The <p> background colour attribute is <p bgcolor="red"> instead of <td bgcolour="red">. The modern CSS version is <p style="background-color: red">.

Example of <p style="background-color: red">...</p>.

Colour Blindness

Many people cannot see red while some cannot distinguish green or blue. Read more in Colour Blindness and What Causes Colour Blindness?.

LCD Displays

LCD (Liquid Crystal Display) devices do not produce light, they just filter light. That means LCD screen manufacturers have to place an electroluminescent panel behind the LCD panel. When you look at the colour black on an LCD screen, you are looking at a bright white light hidden behind the equivalent of a very dark pair of sunglasses. When you look at white on the same LCD, you are seeing the very bright white light through the equivalent of very light sunglasses.

One reason why notebook batteries fail so fast is that they have to supply 100% power to the electroluminescent panel even when most of the image on the screen contains no colour. The next generation replacement for LCD screens, OLED, uses direct light emission which will cut battery drain up to 70%.

When LCD screens fail, they let the screen pixels drop to white or black. A white dot is a bright dot and is covered under some LCD monitor guarantees. A black dot is often excluded unless you have a lot of black dots.

Test your LCD screen by displaying a completely black image. See if there are any white or coloured dots on the screen. Ubuntu linux has a colour test. Try the following tests from your browser. When you are viewing the test screen, maximise the window and use your browser's View Full Screen option.

Select here to test your screen for white dots on a black background.
Select here to test your screen for black dots on a white background.

How do you avoid faulty pixels in LCD screens? My Samsung monitor has no faulty pixels after six years of heavy use. I see many Samsung monitors in use with no faulty pixels. My Asus monitor has no faults and I know fee people using Asus with no problems. My expensive Dell monitor arrived with a black pixel and a guarantee excluding a small number of black dots. Lots of people reported Dell's with dead pixels. Perhaps Dell purchase LCD screens rejected by other brands.

Both the Dell and Asus monitors have guarantees excluding a small number of black pixels. I do not see anything in the old Samsung guarantee to say they will replace the LCD screen if a pixel fails. Some hardware distributors said that some manufacturers refused to replace faulty LCD screens if there were only a few failed pixels. Now all the guarantees say something but the details of the guarantee may not be published online. I think that under Australian law, you should be able to get a replacement unless the guarantee specifically excludes the problem. If you ask the sales person for a fault free monitor before purchase, you are covered by a suitability of purpose consumer law where the shop is responsible for ensuring the product meets your stated requirement. Take a witness with you when you buy.

BenQ have a "Zero Bright Dot" warranty for some of their LCD products. The warranty says missing pixels means, no bright pixels/dots anywhere upon the screen surface, within the warranty period..

January, 2004

Acer now guarantee their LCDs to be 100% pixel error free on both screens and notebooks.

Zeke from the United States (2004) says his Toshiba Satellite A45-S120 notebook has a couple greyish/black dots. Has anyone had a Toshiba LCD replaced or refused under guarantee?

Brent from Victoria, Australia, (2004) says his Magview monitor has a dead pixel and the dealer refused to replace the monitor unless there are at least 6 dead pixels. How do you kill 5 pixels?

I suggested Brent contact Consumer Affairs, Dept of Fair Trading, and his local federal politician. Try both Liberal and Labor candidates, as this is an election year. Someone might do something. At a minimum there should be a warning sticker on the front of the LCD saying the supplier is bottom feeding scum who will not replace broken screens.

Ask your supplier for something in writing before buying an LCD product. Online shops offer the manufacturer's guarantee but often fail to provide a link to the guarantee and many manufacturers have their monitor guarantee buried. Use the shop site contact form to ask about the guarantee before purchase.

If you had a problem with an LCD display, send me a note using the form at the bottom of this page. Please mention the brand and the country where you purchased the product. Manufacturers might improve their guarantees if they get some bad publicity.

HTML

Here are some things to consider when setting colours in HTML and graphics. Choose safe colours for your text, backgrounds, and HTML. HTML colour names are an alternative to hexadecimal specifications but only the common names work in all Web browsers.