praleista 'kalibravima' po 'padarius'

"mooney"  wrote in message news:l24v4c$v72$1@trimpas.omnitel.net...

tu apie miltus ar apie tiltus? pas LCD pasvietimas veikia, pas plasma
INDIVIDUALUS pikselis yra isjungiamas.

Jei lygintumei sukalibruotus LCD (tiek senu kobaltu lempo pasvietimu, tiek
led pasvietimu) ir plazma - tiek vienos tiek kitos technologijos padarius
egzempliorius imant - nesuprantu kaip tau 'matosi' juodesne lcd ... gal
skaistis akis isgrauzia ir nematai spalvu/atspalviu?

Black Level is another oft-quoted but not-fully-understood metric which is a
critical element of good image quality. The ability to create darker blacks
allows a TV to have a higher contrast ratio, a term which will be explained
shortly. The darker the blacks, the greater the appearance of depth and
richness in the image shown. Black level is actually not particularly
complex; it's just a measure of the level of brightness of a display when
showing video black. It usually has as a very low luminance value, such as
0.004 fL (0.013 cd/m2), but rarely reaches 0.0 cd/m2/fL (true black) because
most HDTVs can't achieve this.

To confirm this for yourself, show a black screen on a typical LCD or plasma
TV in a pitch black room, and you will still see some light coming from the
screen, as the photo above demonstrates. So why isn't black on an HDTV
actually equivalent to zero luminance, which is the total absence of light?

On an LCD-based display, black is simulated by the twisted crystals of the
panel being completely shut, along with a polarized layer behind the
crystals, to prevent light from the backlight filtering through when not
required. Yet precisely because the backlight is always on, and the
structure of the crystal array is not perfect, some amount of light will
leak through the crystals and be seen - this is discussed further in the
Screen Uniformity section. More recently, with the advent of local dimming
backlighting, some LCD-based displays can switch off portions of their
backlight to produce close to true black in parts of the image which require
total darkness. Unfortunately this method isn't perfect, as there may be
haloing of light around any brighter parts of the image.

On a plasma display, each pixel can be independently switched off to remove
its light output, and since there is no backlight, in theory a plasma can
produce true black. The reality is that each plasma cell has to be
consistently pre-charged so that it can respond quickly enough when light
output is required, giving plasma its extremely fast response time. The
side-effect of this pre-charging is that there is always some residual glow
in the pixels, and thus true black is usually not possible on a plasma. On
average though, plasmas provide much darker black levels than LCDs.

It should be noted that what some consider the king of black levels, the
traditional CRT TV, does not necessarily achieve perfect black either. A
CRT's black is darker than either plasma or LCD, primarily because a CRT can
simply have its electron beam avoid lighting up particular portions of the
screen. However when displaying any scene containing brighter elements, some
stray light may affect the dark areas of the screen. In other words, when a
CRT is showing an all black screen, black levels are pretty much true black,
but when displaying a normal scene containing a mix of brighter and darker
elements, black levels on a CRT are not true black, and may be similar to or
even worse than a plasma screen.


"Jonas Vingis"  wrote in message
news:832762086401995248.120054jonas.vingis-kaimas.lt@news.omnitel.net...

"mooney" <mooney@moon.com> wrote:
> sapnuoji, arba kazka painioji konkreciai

Nei sapnuoju, nei painioju. Aš kalbėjau apie žiūrėjimą šviesoje.