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Laptop Displays: Technical Language Explained

Laptop screens: Technical language explained

Displays are, of course, the central component on all laptops, TVs and phones. However, the language manufacturers use to describe them is often littered with technicality: contrast ratio, black level, and so on. To counter the confusion the use of such terms could potentially cause, we've composed a handy blog entry on their meanings. We hope you find the information here presented, helpful.

Technical language explained

1. Contrast ratio

A term consistently quoted by manufacturers. They are particularly fond of utilizing contrast ratios, (such as 10,000:1.) because the numbers, composed as they are of a great number of zeros, look sufficiently impressive. Put simply, the contrast ratio is the ratio of luminance in existence between the brightest and darkest colours, (between white and black,) on a display. Higher contrast ratios are thus considered better because they realistically define screen images. The major problem with contrast rations, however is that no-one uses a standardized or official test to determine them. Thus, subjective interests can affect results, leading to inexpensive displays being marketed with impossibly high contrast ratios. The standard unit of luminance is a Nit: the higher the nit rating, the brighter the display. Laptops and phones ordinarily have a rating of between 200 and 300 nits, with a rating of 500 or more being exceptionally good. Televisions, in contrast, display a brightness which often exceeds 1000 nits.

2. Black level

This term relates to the display’s ability to present dark images. If you’ve ever watched a film on a low quality screen, you may have noticed that many dark aspects of a scene are omitted altogether. A display’s black level is expressed in the form of a number: the lower the number, the better the screen is at rendering the colour black. The reverse applies to white levels: the higher the value the better. The maximum white level attainable is 255. A good quality screen capable of displaying an even sense of white will thus possess levels in close proximity to that figure.

3. sRGB

 the term used to refer to the standard colour space created by a collaboration between Microsoft and HP in 1996. A colour space is, in essence, the standard range of colours displays should be able to produce. An average display, however, can only display between 60 and 75% of colours in the sRGB range. Only an IBS display is capable of presenting the full spectrum. Here, as with contrast ratios, however, many different standards of measurement apply. For this reason, comparisons between screens are only fruitful if their colour space percentages are deduced using the same testing standard.

4. Uniformity issues

A term used to refer to brightness variation within an LCD screen. On an LCD panel, for the display picture to be visible, a light must be shone through the display. Ideally, this light would be of uniform brightness; however there are instances in which a single screen can have varying qualities of brightness. A problem such as this is often particularly prominent when watching a dark scene or using a mobile device.

5. Banding

A term used to refer to the seemingly abrupt layers of colour that occur on a display, within the gradated colour system. An ideal screen would display images in smooth and subtle gradations of colour. Most however lack this perfect capability, with banding often occurring within darker hues.

6. Dithering

A term which refers to a technique used by panels when attempting to produce a colour they are otherwise incapable of properly displaying. For example, suppose a display was incapable of producing the colour purple. Instead, it may attempt to represent the colour using red and blue pixels. This technique is often used to try and combat banding, however, it can have some odd results, among them the creation of shimmering blacks within the gradient banding image.

7. The screen door effect

The term used to refer to a display within which there are noticeable gaps between individual pixels. In technical circles, this effect is commonly referred to as “dot pitch.” A low dot pitch is indicative of small pixels with relatively small, (and at times difficult to discern,) spaces between them. A high dot pitch refers to the reverse. Dot pitch is a relative problem based, as it is, on the distance between the display and the user. Thus, it is more frequently cited as a noticeable problem on mobile devices.

 

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