Talk:Contrast ratio

message: I added sources to perhaps one half of all the statements that could use one. I'll try adding some more references soon. Santtus 12:06, 11 January 2006 (UTC)
thread_title:  Removed the unsourced template 

message: I've updated the first couple notes to the new format, which can match up the numbers more accurately. Shawnc 23:19, 20 April 2006 (UTC)
thread_title:  New reference format 

message: "This may not sound too bad though, as the static contrast ratio of a human eye is somewhere between 100:1 - 1000:1 so the details in those highlights might not be resolvable anyway."  This can probably use a citation and be re-worded a bit, in particular "sound too bad" and "might not be resolvable". Shawnc 00:06, 21 April 2006 (UTC)
replies: text: That 100:1 - 1000:1 thing was from an article, although I summed up the controversy surrounding the issue. I'll try to look at it soon enough. Santtus 15:12, 26 April 2006 (UTC)
replies: text: You may want to edit the article on eye as well, because it states only the 100:1 figure. GreenGrass 14:58, 7 May 2006 (UTC)
replies: text: Was in the middle of editing, but I couldn't finish my writing before getting a headache ;) I'll finish it later. I checked from various sources that 100:1 seems to be fine - it's the most often quoted value. Found some info on contrast sensitivity too, but it measures minimum noticeable contrast, not maximum. Now I just got one more question. How do you define maximum contrast a person can see? I'll try to find an answer for that.. Santtus 13:18, 9 May 2006 (UTC)
replies: text: Well, as the performance of an eye is apparently limited by the performance of its lens, it should be easy to measure its static contrast ratio. You can fill 50% of your FoV with a white object, and 50% with a black object (with sufficiently high ratio between their diffuse reflectivity). Then you place a small text on the black object with a brightness just a bit more than the background. Afterwards, you gradually increase the brightness of the text until it becomes resolvable (in layman's words: "readable"). Than you measure the contrast ratio between the luminosity of the text and the luminosity of the white object, multiply it by two, and there you have it. (I took the last number from my head, it should be the minimum contrast necessary for the eye to detect edges of letters, which is probably a bit subjective issue). GreenGrass 19:55, 15 May 2006 (UTC)
thread_title:  This sentence 

message: It appears that the phrase "extraordinary contrast ratio" doesn't mean anything special, except that a someone feels that the contrast ratio is great. I've found no examples of professional use of that phrase, so I'll revert the changes unless I'm otherwise convinced. Santtus 09:12, 13 June 2006 (UTC)
thread_title:  Extraordinary contrast ratio 

message: This paragraph:
Many manufacturers of display devices favor the use of the full on/full off method of measurement, as it will effectively cancel the effect of the room completely, giving as high ratios as possible. Equal proportion of light will reflect from the display to the room and back in both measurements, as long as the room stays the same. This will inflate the light levels of both the "black" and the "white" measurements in the same proportion, unaffecting the black/white luminance ratio.
is simply not true! If Lw, Lb and Lr are the white, black and room luminosity, respectively, then Lw/Lb might be very different from (Lw+Lr)/(Lb+Lr). The reason manufacturer prefer this contrast measurement is that it might give them higher contrast, than say the ANSI contrast. See for example the CRT (global) contrast vs. LCD (global) contrast in the previous comment.
I would suggest the following phrasing:
Many manufacturers of display devices favor the use of the full on/full off method of measurement, as it will give higher contrast ration over the ANSI contrast measurement method.
 previous comment by user:yuvalaviel
I wrote that paragraph with assuming otherwise unilluminated room, with Lr = 0. Now that could be mentioned. 
Actually it has not been established what is the most usual level of illumination in the testing room. If there is absolutely no other light than that what reflects from the screen, then we can establish that a fraction f (0<f<1) of the light reflects from the screen to the room and back. Then Lw/Lr = (Lw * (1+f)) / (Lr * (1+f)). 
Judging from overly inflated contrast ratio figures generally presented in the marketing literature, it doesn't seem believable that the manufacturers would have generally performed their tests in any significantly illuminated environments. 
Perhaps someone can shed light on this situation? 62.220.237.65 23:04, 29 March 2007 (UTC)
thread_title:  Methods of measurement 

message: I'd like to see some mention of contrast ratio as a marketing term for LCD computer monitors.  There seems to be quite a bit of emphasis on contrast ratio.  Is it really significant and measured the same across manufacturers? --24.249.108.133 22:19, 13 April 2007 (UTC)
thread_title:  Contrast Ratio as marketing spec 

message: hmm, I have let the mention of "infinite contrast CRTs" to stay, but I'd wish to find a source to mention how it actually is. The monitors I've owned have shown visibly grey "black" level. For a reason or another, the contrast ratio was not being advertised in the time when LCD monitors where unavailable. When did they start measuring and advertising contrast ratios anyway? (forgot to sign) Santtus 22:02, 5 September 2007 (UTC)
replies: text: The contrast ratio is nearly the same on all CRTs and it also depends on the settings, if you make the picture dark enough (but not toot dark), you can get very high contrast ratios. It also depends on room lighting, it is best for teh contrast if you use the monitor in a complete dark room. --MrBurns (talk) 13:45, 10 December 2008 (UTC)
thread_title:  Observation form CRT monitors 

message: "The trick for the display is to determine how much of the highlights may be unnoticeably blown out in a given image under the given ambient lighting conditions". Could someone please clarify this sentence? I don't understand what is meant by "blown out" in the article's context. Is there a less technical term for it, perhaps?  —Preceding unsigned comment added by 98.221.120.172 (talk) 20:42, 18 October 2008 (UTC)
replies: text: I'm pretty sure the author is referring to "blown out highlights", also called clipping (photography). --68.0.124.33 (talk) 05:08, 14 December 2008 (UTC)
thread_title:  Blown out? 

message: Could I ask someone for a better comparison with regard to what is a "good"/"desired" ratio, as to what is a "low-end"?  For example; a link to a table of products showing their current ratios? -- Mjquin_id (talk) 19:37, 21 August 2009 (UTC)
thread_title:  Comparison 

message: I'm here as a result of some confusion while comparing 2 monitors at NewEgg.com.  One monitor has a Contrast Ratio of "2000:1 ASCR" while the other has "DC 2000:1(1000:1)"
What does this mean, and how can the wiki be edited to explain the difference ?  —Preceding unsigned comment added by Jonny Quick (talk • contribs) 06:35, 4 September 2010 (UTC)
thread_title:  Different Ways of Measuring Contrast Ratio 

message: I added the copyvio template thinking it would just be a simple tag, but I see that I opened up a can of worms and right now and too tired to really go through the process. I noticed quite a bunch of text was copied word for word from a website that copyvio notwithstanding is not very reliable. B137 (talk) 04:02, 21 April 2015 (UTC)
thread_title:  Copyvio 

message: 1 "contrast ratio" mainly is a wide-spread pleonasm.
2 The International Lighting Vocabulary CIE S017/E:2011 states:
  contrast
  1. in the perceptual sense: assessment of the difference in appearance of 2 or more parts of
  a field seen simultaneously or successively (hence: brightness contrast, lightness contrast,
  colour contrast, simultaneous contrast, successive contrast, etc.)
  2. in the physical sense: quantity intended to correlate with the perceived brightness contrast,
  usually defined by one of a number of formulae which involve the luminances of the stimuli
  considered: for example by the proportional variation in contrast near the luminance
  threshold, or by the ratio of luminances for much higher luminances
3 Contrast is often specified by the ratio of luminance levels, so this ratio should not be called "contrast ratio", because it rather is a luminance ratio.
4 There is no such thing as "luminosity" in display engineering and visual perception.
5 Contrast between two optical states is not limited to white (100% RGB) and black (0%). Why should this "cancel out the effect of the room and result in an ideal ratio"?
6 "Brightness, as it is most often used in marketing literature, refers to the emitted luminous intensity on screen, measured in candela per square metre (cd/m2). The higher the number, the brighter the screen."
Marketing publications are not the right guide to solid Wikipedia articles.
"Brightness" is not the emitted "luminous intensity", "luminous intensity" is not quantified in candela per square metre (cd/m2),
7 The concerns listed above are not the only ones that make this article at least doubtful. Complete revision is recommended in order to avoid continued confusion of the readers.
panjasan (talk) 06:58, 11 August 2015 (UTC)
thread_title:  poor status of article