The "black and white" Tag and How it Should be Applied

It has come to my attention that the tag “black and white” is possibly being misused. This thread is to discuss it, and how the tag should be applied from now on, as well as fixing tagging on several past images.  
[tl;dr: Should grayscale images be tagged with black and white?]
 
Currently: Three tags are tied together; monochrome, grayscale, and black and white.  
Right now “black and white” implies both the “grayscale” tag and the “monochrome” tag.
 
What is at question is how the tag “black and white” is applied.  
Here is an example of some images found under the “black and white” tag:  
>>1353804t (deleted)  
 

 
Images similar to the third one are what are in question.  
By definition, a black and white image is exactly that. Black, and White. And does not contain varying levels of gray. Like the first image.  
However the issue comes in due to “black and white” being used as a sort of slang term for grayscale. Like “those old black and white tvs” Or a “black and white photograph” When referring to this:  

 
And currently, a google search for “black and white photo” gives a majority of images like this:  

 
So the question is: How do you see black and white defined. And do you feel it should apply to grayscale images?

It should be used for grayscale in the manner used by pre-color non-sepia film, IMO. Note we do not have “blue and white” or such for other monochromatic stuff.

“Monochrome” means values of one color. The “color” doesn’t have to be black. B&W and Grayscale images are “monochrome” but the image could be shades of red or blue. Example:
 

 
“Grayscale” means more than 1 bit of black - in other words the image has values that are not just WHITE and BLACK. For example, everything except for the farthest left scale on this image is “grayscale”, representing values of WHITE to BLACK in 2, 3, 4, and 8 bits:
 

 
B&W images can show “tones” by varying the position and number of BLACK and WHITE dots, as in these HALFTONES:
 

 
But they are still only using BLACK and WHITE - the linescreen determines whether the human eye perceives individual dots or “the perception of a continuous tone”.
 

 
IGNORING HUMAN PERCEPTION Black & White images are only using black and white dots - every pixel is either a 0 or a 1 - regardless of how the human eye is being tricked - even if the image is halftoned or using a stocastic tone, if the pixels are just black and white, the image is B&W.
 
Grayscale images have values other than 0 or 1 per pixel; whether it’s 2, 4, 8, or even more bits per pixel.
 
So if an image is grayscale I think it should be tagged grayscale.
 
Grayscale images are almost certainly also monochrome.
 
B&W images I think should only be those that are 1 bit images, such as bitmaps or monochrome halftones.
 
For example, line art is B&W. Unless it’s grayscale.
 
Grayscale (although I didn’t tag it as such, because it’s a sketch):
 

 
B&W Lineart:
 

 
Fixing all the images though - applying this uniformly across the site - will be very difficult, though.
 
Because as artists we know that 1 bit images are B&W, and 2 bit or 4 bit or 8 bit grayscales are “Grayscales”.
 
But the marketing terms for B&W photography and TVs - as noted - includes halftones. Technically they’re B&W - but they are sold as continuous tones, even though “the tone” is only an exploit of a flaw in human perception.

While I would love to get highly technical and argue the semantics of highly graphical uses of pure black and white, Zeb said it himself. “Black and white” has become slang for grayscale. I see no problem with any of the implications, we just need to define and clean up. I propose:  
Monochrome: Images that only use tints and tones of a single color.  
Black and white: Monochrome images that use pure black and pure white, with few midtones.  
Grayscale: Monochrome images that are completely desaturated.  
So black and white would imply grayscale, and both would imply monochrome, but no implications in the other direction.
 
I have no issue with a little overlap, such as a single spot of color in a grayscale image, or inking-style shading techniques to achieve grayscales on black and white images. It shouldn’t be that much work to separate the rest out.

@Zeb  

 
Note, that if you apply it to all grayscale images, there will be no reason to have black and white at all, it will be just an alias of grayscale.

I think the way the implication is set up right now is fine and should be how we tag. Pure black and white images are by definition also grayscale, everything with more tones is ‘just’ grayscale.

@WingbeatPony  
So… Should this for example be tagged grayscale (NOT black and white)?  

 
And should be theese tagged black and white?  

 
(>>1352394, >>1178914, >>1038897)
 
@WingbeatPony  

 
I have always used grayscale + partial color combination for this case. (Same with monochrome and B&W)

@Kot Kompot  
Sounds like you’re on the same page with me, then. That’s exactly right. In terms of specificity, it goes monochrome -> grayscale -> black and white.

@WingbeatPony  
@Kot Kompot  
For single spots of color, or extremely specific coloring in otherwise monochrome images, we have the neo noir tag. Which implies monochrome + partial color.
 
“Note, that if you apply it to all grayscale images, there will be no reason to have B&W at all, it will be just an alias of grayscale.” I still think there would be a difference between “grayscale”, and “black and white” that would keep them from being aliased. While black and white would cover both sets of images you linked. Grayscale would only apply to the first one.
 
I see “black and white” as more of an overall type of tag. While grayscale applied to only the images with a….well, grayscale.  
So all of the images you linked would be “black and white” but only the top one includes “grayscale”.
 
 
@WingbeatPony  
“So black and white would imply grayscale, and both would imply monochrome, but no implications in the other direction.” I actually think black and white should not imply grayscale. Since many images that apply for black and white [even right now, under the current system] are not grayscale in any form.
 
I actually think “grayscale” should be the one to imply black and white.  
[And both implying monochrome]

@Zeb  
I agree with this.
 
Implications:  
grayscale -> black and white, monochrome  
black and white -> monochrome

@Zeb  

 
What you are talking about, is simply to swap black and white and grayscale.  
There are tons of images tagged, and these tags have been as they are for a long. Not sure they need to be changed, even if in some interpretations they look that way.
 
For me, I think that image with only black color and white color and no gradient is still technically “grayscale”, just degenerate case of it. And actual grayscale image can’t be black&white (in strict terms, not slang) because black and white means 0 and 1, and gray is neither.

@DragonWraith  
That sounds reasonable.

If I posted a greyscale image and someone added a black and white tag to it, I’d take it off. Black and white is black and white, if there are gradations or halftones that aren’t visibly distinct as black/white at maximum resolution, they should be tagged as greyscale. Or grayscale, I guess, since 19th Century Hipsterism is Derpi’s preferred style guide, APPARENTLY.

@Kot Kompot  
@Zeb  
I would think that partial color would be mutually exclusive with monochrome and the rest due to the nature of the tags. I’ll also admit I find the use of the neo noir tag a bit iffy, but that may be because it has noir in it so I only really see it being used on images like the provided example.

@Solitude  
Regarding the neo noir tag specifically, that is the actual name I eventually tracked down for that image style; this stems from the fact that, although the technique can be used for any sort of image, its origins (and nearly all of its original uses) trace back to the noir genre. There is nothing intrinsically tied to noir in the style itself.

@DragonWraith  
Noted.

@DragonWraith  
in my opinion i think the “neo noir” tag is being overused. neo noir does mean there are partial color, but neo noir shouldn’t be used every time there is a partially colored picture. i’m seeing pictures tagged “neo noir” when they’re just WIP sketches with a bit of color dashed on them, and i don’t think it really works with those. “partial color” is fine for those, but i feel that ‘neo noir” should imply to more finished images. B/W sketches with blush stickers slapped on shouldn’t cut it.
 
tl;dr >>402865 [NSFW] should not be in the same tag as >>1045099

@pearlyiridescence  
That’s kinda what I meant too. I’d thought the tag would be more for images that are more dark and have an element of bright color for emphasis.
 
Something more akin to
 
 

 
Not so much
 
 
 

 
But with the tag description and DW’s post the tag has a broader use. I’m just confused on when to use that or partial color.
 
Back on topic: is there a decision on how to use the other tags? Monochrome for images that are a single color, grayscale for images that are varying shades of grey, black and white for images that are expressly black and white? Or am I mistaken?

Ain’t nobody use limited palette no mo’.

@TexasUberAlles  
Because partial color is for images where only part of image is colored and part is not (i.e. monochrome). And limited palette means that while full image may be colored, the set of colors used is limited. Technically yes, you may call all monochrome images “limited palette”, but I think this tag is specifically purposed for images like this and provides convenient way to distinguish the from these .

Let me summarize this topic a little.
 
First and most general question is how we differentiate black and white and grayscale tags. There are three possibilities:
 

 
var. 1 - Nested. This is how the things are now. Black and white for bi-color, grayscale for all images in shades of gray including images with only two extreme colors. @WingbeatPony, @Yoshimon1, @TexasUberAlles, @Kot Kompot
 
var. 2 - Use grayscale for narrowing black and white, somewhat similar to partial color with monochrome. @Zeb, @DragonWraith
 
var. 3 - Disjoint. Grayscale must have an actual “scale” or at least be gray; and black and white is strictly for one-bit images. @Ciaran (you agreed with @DragonWraith, but in your post you stated it in other way.)  

 
Second. How is partial color related to monochrome? (Maybe it should be moved to dedicated thread.)  

Searching for monochrome I personally don’t mind if some images with colored blushing pop up. If I do - I can simply use monochrome, -partial color as search query. Look at this diagramm:
 

 
@Solitude Now there are three possible sets of search results (7 if you count all combinations), and if you state that those tags are mutually exclusive - only two will left. Here’s few examples:
 
black and white AND partial color  

 
monochrome AND partial color  

 
almost borderline, but I still tagged it grayscale AND partial color  

 
borderline, not sure about it, most likely just partial color  

 
partial color AND NOT monochrome (Focused character is fully colored)  

 
@Zeb, @DragonWraith Note, that in common sense you can hardly call any of above “neo noir”. (although you tagged some of them as such) “Neo noir” is this >>1281306 and maybe this >>1325533. The fact, that neo noir implies monochrome and partial color does not mean that all images tagged monochrome, partial color should be tagged neo noir. On the diagram “neo noir” would be only a subset of A, not the entire A. However @pearlyiridescence and @Solitude have already said that.
 
 
And the third (small). No matter how we define black&white and grayscale, there is still an additional question of how strictly we define bi-color images (only one-bit or more relaxing). Because there are images with rasterizing artefacts, images with little gray parts and images that are not black but very dark gray and white. (example is in my other post)

@Kot Kompot  
Maybe I’m missing something. But why do you list this image as Grayscale and partial color?  
What makes this image grayscale?  
 
From the talk in this thread, My understanding of that image is it would be Monochrome, and possibly black and white.
 
I do agree the Neo Noir tag is applied too liberally right now.  
But I do say that it does apply to images such as these:  
 
Reason: The tag was created and defined as: “Use for images that are almost entirely monochrome, but have an element (or a few elements) fully colored for emphasis.”  
And with lineart with a colored blush, or monochrome art with colored eyes. The purpose of the color is to highlight and emphasize those areas. Which is the purpose the neo noir tag was created for in the first place.
 
 
As for possible options for defining how we apply black and white, and grayscale: I still personally feel that grayscale images do count as a form of “black and white” as the term has become to be known today. And that’s where my vote will go. So: Having the tag “grayscale” imply “black and white”. Instead of how it is now. [B&W implying grayscale]  
Though I will accept if the final decision is to separate the terms.
 
Additional: While I won’t be undoing all of the tag changes, I do ask that people not go ahead an alter these tags on a large number of images while the discussion is still taking place. There is no rush to have everything changed at this moment.  
Of course, changing these tags on images where they grossly don’t apply is still fine as normal. [Such as a full color image tagged monochrome somehow.]

@Zeb  
see, i don’t think line art with a bit of color should count as neo noir. nothing about that makes me think of “noir”. partial color is perfectly fine for those images and they don’t need a subsequent tag that honestly, doesn’t describe them well.

@Zeb  

First of all, this image may be only partial color if you think that there is too much coloring to count as monochrome. It’s borderline as I said. But if you willing to add some tags from “monochrome family” (for it is just lineart with some coloring) - then it will be grayscale. And what makes it such is that firstly it has some part in the shades of gray and secondly - lining itself is not all-black, mostly gray.  
 
So, in my terms (var.1 on the chart) this image will be grayscale and monochrome. And also black&white if for some reason I decide that there isn’t enough gray.  
And in your opinion (var.2) it must be black&white and grayscale (and monochrome obviously). Unless you think these gray parts are not enough to qualify as grayscale - in this case just black and white and monochrome. And I have no idea how it can be only monochrome. Because lining is not colored and thus at least one of (grayscale, black and white) is applicable.

@Kot Kompot  
Hrm. Makes sense. I tend to be a bit too literal with how I interpret tags, is the problem.