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Here are some questions that many people concern, Is it better to have a higher contrast ratio or a lower? I'm looking at LCD one has 250:1 and the other 500:1, then there's reslution does that mean the clarity or refresh rate? does it mean clarity or does it mean how fast the picture refreshes.
Contrast ratio is the difference in brightness between blacks and whites. For example, 500:1 is staying that Whites are 500 times brighter than Blacks. What does this means in layman terms? This means bright whites, darker blacks and everything in-between is more vibrant and accurate.
Higher the contrast ratio, the better the colors you will have on your image. This spec is unrelated to clarity, resolution and refresh rate. It is specifically telling you about color quality.
Picture refresh rate would be response time. You will see the term in ms. 30ms is slow. Good LCD response time is under 10ms. Excellent is under 5ms.
Contrast ratios are a big marketing tool by the manufacturers and one that is not easy for consumers to grasp. Essentially, this is the measurement of the difference in brightness from the darkest to brightest portion on the screen. The problem is that this measurement will vary throughout the screen. This is due to the slight variations in the lighting behind the panel. Manufacturers will use the highest contrast ratio they can find on a screen, so it is somewhat deceptive. Basically a higher contrast ratio will mean that the screen will tend to have deeper blacks and brighter whites.
Resolution can be seen in computer or video terms. Computer terms would be two values, such as 1920x1080. Video terms would be 480p, 720p, 1080p. The correlation between the two types of terms is the last value. 1920x1080 is the same as 1080p. 1280x720 is the same as 720p.
Digital frame contrast is a measure of LCD feature system, we defined it as the ratio of the luminance of brightest to darkest color. Which contrast number make people feel better? A high contrast ratio is a desired aspect of any LCD display, the higher the number, the more vivid picture is will be. Various contrast methods of measurement for a LCD, here is some method normally used.
Methods of measurement
Many Digital Frames Contrast manufactors favor of full on/full off method of measurement, as it cancels out the effect of room. Equal proportions of light reflect measurements, from display to the room and back in both black and white. As long as the room keep the same. That will inflate the light levels of both measurements proportionally, digital frames contrast leaving the black to white luminance ratio unaffected.
Another measure for digital frame contrast is the ANSI contrast, the measurement is done with a test image, which checker board patterned where the luminosity values are measured simultaneously. includes the potential of romm including the effects into the measurement, this is a more realistic measure of lcd system capability, but if the test is not performed in a room that will be close to ideal.
It is also common, digital frame contrast market only the dynamic contrast ratio capability of a display, when better than its static contrast ratio, which should not be compared directly to the static contrast ratio. A static 5000:1 plasma display contrast ratio will show superior contrast to an LCD display with 5000:1 when input signal contains full range of brightnesses from 0 to 100% simultaneously. However they will be on par if the input signal ranges changed only from 0 to 20% brightness.
Human eye can normally accept 250:1 contrast ratio, in most cases, 300:1 contrast ratio can reach very good piture. Of course, the bigger the better. Now most of the digital photo frames are in the 250:1 contrast ratio or above.
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