Talk:Lightness

message: These describe the same color attribute, and "lightness" is the term which is coming to be used in modern models like CIELAB and CIECAM.  The value article should be merged into this one, and then redirected here. --jacobolus (t) 20:02, 19 September 2007 (UTC)
replies: text: That's fine.  The article can explain that both words are used for the concept, and the value article can redirect here.  The point is that we have a single concept, so it's silly to duplicate the information about it on two different articles.  The popularity of the term "value" comes mostly from Munsell's use, as far as I know.  More recent models like CIELAB and CIECAM02 use the term "lightness".  --jacobolus (t) 04:24, 1 November 2007 (UTC)

text: Comment. Is the term value used in painting to mean something not covered in the value article? If we mean that lightness=value=correlate of perceived brightness, I'm for merging them.--Adoniscik (talk) 14:58, 3 February 2008 (UTC)
replies: text:  Does value mean something different in painting than its use by Munsell?  I'm not aware of what that definition is.  --jacobolus (t) 22:10, 3 February 2008 (UTC)
replies: text: I just checked a bunch of books, and they appear to agree that value is lightness or something reasonably equivalent.  For example, this one.  And this one pretty much says that artists use the Munsell system. Dicklyon (talk) 00:43, 4 February 2008 (UTC)
thread_title:  merge from value 

message: Could someone please add caption text to the first image (ColorValue.jpg)?  —Preceding unsigned comment added by 79.176.137.250 (talk) 16:48, 28 November 2008 (UTC)
thread_title:  What is the diagram? 

message: "Various color models have an explicit term which places the color on a scale from utter black to pure white. The HSV color model and Munsell color model have an explicit value, while the HSL color model uses a related parameter called lightness instead."
The "explicit value" of HSV refers to something different; i.e. the value/color is not "on a scale from utter black to pure white." The HSL parameter lightness is the one that's closer to the Munsell system.
"In the HSV and Munsell color models, a color with a low value is nearly black, while one with a high value is the pure color."
This is not true of the Munsell system. HSV is the oddball here. It also contradicts the first sentence I quoted.
As for the rest of the article, it was in need of cleanup (forming paragraphs out of loose sentences, etc.) You were right in that I deleted a good bulk of stuff on accident. SharkD (talk) 06:19, 29 June 2009 (UTC)
replies: text: Further, in the image, it might be a good idea to put the word "luminance" somewhere on the x-axis. It's explained in the caption, but it might not be enough. SharkD (talk) 06:33, 29 June 2009 (UTC)
thread_title:  Some problems with the previous version 

message: I came here to learn about 'value' from the fine arts perspective. 
The first section is hilariously wordy and inaccessible. "... is a representation of variation in the perception of a color or color space's brightness. It is one of the color appearance parameters of any color appearance model."
Would it be that absurd to just say: "It's how bright a color is." 
Then, the rest of the article is just gibberish to someone, such as myself, from a fine arts background, and offers nothing of substance as to how value relates to or is used in the fine arts. This article is horrible and should be rewritten by someone who isn't copy pasting from a science textbook.  — Preceding unsigned comment added by 45.47.156.179 (talk) 22:22, 30 October 2015 (UTC)
replies: text: Um, yes, it would be absurd or, more to the point, simply wrong. Lightness does not equal brightness in color theory. I’m not saying the article can’t be improved – it most certainly can. But not in this way … If anything, you need more words to clearly point out the difference between lightness and brightness, as it is obviously easy to confuse them. --Uli Zappe (talk) 07:48, 11 November 2015 (UTC)
thread_title:  Extremely convoluted article 

message: The reference [1] (Brightness vs. Lightness) is to a YouTube video that describes what a guy believes that the Photoshop settings of brightness and lightness mean.
It's ridiculous, there are already several accepted discording definitions of lightness and brightness in the various fields, we really missed the photoshop one.
It discredits the whole articles of Lightness and Brightness, those who originally wrote them have no idea about these things and managed to add confusion to an area that was already fill with confusion to the brim.
(BTW I'm not really an expert, don't ask me to fix it; maybe until a real expert comes the best thing would be to delete these articles altogether)
Gabrolf (talk) 14:53, 26 January 2017 (UTC)
replies: text: It's confusing to you because you're skipping the part of the sentence that explains the difference: ‘judged ... transmitting.’  — Preceding unsigned comment added by 77.61.180.106 (talk) 01:39, 19 June 2021 (UTC)
thread_title:  Ridiculous youtube reference (Brightness vs. Lightness) 

message: FTA: Neither option turned out to be quite correct; scientists eventually converged on a roughly cube-root curve, consistent with the Stevens's power law for brightness perception, reflecting the fact that lightness is proportional to the number of nerve impulses per nerve fiber per unit time.[Hunt 1957]
There are a couple of problems with this part. First, scientists didn't in the end converge on a cube-root curve. I'm not bickering here about the fact that the underlying function probably isn't really a power function but more something based on Michaelis–Menten kinetics, after all the article says ‘roughly’, but about the fact that the stated gamma isn't the current value, which is context dependent but (according CIECAM02, which is isn't quite the most current but close, and a back of the envelope computation) in the range of about 1.6 (light) to 2.1 (dark). I think the root cause that the discrepancy is so large, rather than just being a bit off due to intervening advancement of understanding, is that Hunt is talking about brightness, not lightness, which has (again, according to CIECAM02) double the gamma, so about 3.1 to 4.1.
There's also a problem of chronology. Now, I know the impersonal writing style is de rigeur in much of academia and I myself was taught to write this way, but it's usually a terrible idea and Hunt 1957 is good example where it can appear especially disingenuous. Reading that article, phrases like ‘in a paper published’ and ‘it was concluded that’ made me think initially that the findings were those of others, perhaps even crystallised ideas generally held in the field. But checking the references it's clear it's actually talking about a previous paper by Hunt himself, published in 1953. So the article basically says ‘Hopkinson's 1956 results support my model’; reading Hopkinson's reply leaves me with the impression that Hopkinson wasn't so sure. Either way, Hunt's work isn't based on Stevens's, it couldn't have been because Hunt's work predated it by four years and Hopkinson's work by half a year.
And apparently the opposite wasn't true either. The fact that Hunt 1957 and Stevens 1957 were published in the same month appears to be a coincidence. Stevens takes his brightness data from work done by Hanes in 1949. (Which probably should be mentioned in the article. Even though Hanes's work was about brightness rather than lightness it's still relevant.)
And the clumsy way the snippet from the article was phrased makes it seem like there is some direct causal connection between a perception following Stevens's law and the proportionality to nerve impulses. As far as I can tell this isn't true; Stevens's law is purely empirical. The connection between actual chemical and physical processes and sensations is currently thought to be the Michaelis–Menten model. Which also means that although Steven's work may have historical significance and should hence be mentioned in the chronology, it doesn't directly relate to current understanding and its mention in this snippet is out of place.
Now, since I've mentioned CIECAM02, I feel obliged to say that the article discusses its technicalities and the basic model, but there are still a number of parameters which need to be fitted to fix the lightness scale. What I'm saying here is that even if the model is correct, it must still be fitted to good data to get the right parameters so that the resulting whole describes human colour vision. The article should explicitly cite the studies that provided the data underlying the scale.  — Preceding unsigned comment added by 92.67.227.181 (talk) 14:23, 2 June 2022 (UTC)
thread_title:  Cube-root snippet 

message: FTA:
#The Munsell value has long been used as a perceptually uniform lightness scale.
#A question of interest is the relationship between the Munsell value scale and the relative luminance.
#Aware of the Weber–Fechner law, Munsell remarked "Should we use a logarithmic curve or curve of squares?"
#Priest et al. provide a basic estimate of the Munsell value (with Y running from 0 to 1 in this case): V = 10√Y
I'll discuss these in order.
#This has been true from 1915, when the first atlas was published until this gradually stopped being true in the fifties. (The reason was on the one hand that as early as in 1943 the focus started to shift from perceptual uniformity as an aim in and of itself, making backward compatibility at least a secondary aim, and the shift towards formula-based approaches.)
#Shortly after 1906 Munsell decided to use a parabolic scale because he thought that would yield a visually uniform scale. The greys in his 1915 atlas lie smack bang on a parabola.
#This was in 1906, before his atlas was published. It isn't true that the greys in the atlas were tweaked visually and a parabola was post facto considered a good match for them. Rather, the greys were set to fall on a parabola with the help of a photometer.
#This isn't a ‘basic estimate’. The 1920 article's goal was to show what relationship between Y and V Munsell used. It was already known Munsell had used a photometer to arrive at his greys. Looking at the graph in the 1920 article it's clear that Munsell had worked accurately, although his reference grey, which should have been an ideal 100% reflector, was in reality more like 93.6%. (This discrepancy has apparently never been fully explained.) In theory this formula should hold exactly if one uses the same reference Y as Munsell did, although there are limits to how accurate paint can be mixed.
So yeah, the article jumps backwards and forwards in time and gets causality wrong.  — Preceding unsigned comment added by 92.67.227.181 (talk) 01:10, 3 June 2022 (UTC)
thread_title:  More chronological problems 

message: In 1996 Hård, Sivik & Tonnquist published experimental results that are relevant to the article.  — Preceding unsigned comment added by 92.67.227.181 (talk) 16:56, 11 June 2022 (UTC)
thread_title:  1996 

message: FTA: Munsell, Sloan, and Godlove launch a study
When you say ‘launch a study’ you implant an image in the reader's mind of about a hundred participants, government funding and oversight, that kind of thing. But the study that their formula was based on was just them and a couple of employees saying how many brightness differences they just about noticed between reflectance steps. They didn't show if that would be a good measure for brightness, I don't know if they were biased, I don't even know if they were lying or even if Munsell, Sloan & Godlove reported truthfully on the findings.
The second study they did had fourteen participants, some of them outsiders, and they essentially confirmed Munsell's original parabolic curve. To within experimental error, I'd say. Which of course doesn't mean the curve ultimately is a mathematical parabola, the underlying connection might be – in fact, is – different, just that whatever curve it is, the data that was available is very well approximated by it.
The only reason we need to mention them at all is because they ultimately managed to influence CIELAB. And how did that happen!? I'm used to people adding stuff to Wikipedia not having actually read the references they cite, but how did the CIE not catch on?  — Preceding unsigned comment added by 92.67.227.181 (talk) 15:29, 12 June 2022 (UTC)
thread_title:  1933 

message: Alexander Munsell's name is used once without telling us who this is - - -
"1933 
Alexander Munsell, Louise Sloan, and Isaac Godlove launch a study..."
Is this a relative of Albert Munsell or an error that is meant to be Albert? There's no Wikipedia listing for this person other than this article.
Thank you for your attention, Wordreader (talk) 23:36, 7 March 2024 (UTC)
replies: text: Alexander Ector Orr Munsell (1895–1983) was Albert Henry Munsell's son. You can read Dorothy Nickerson's  obituary of A.E.O. Munsell here. Albert Munsell died in 1918, so certainly wasn't doing scientific work in 1933. –jacobolus (t) 23:44, 7 March 2024 (UTC)
thread_title:  Who is....