NEW CLUSTER STUDY THREAD!

[Faceless]

This thread is interesting to me, and I will definitely be experimenting with this at some point in the future. I think I'm often guilty of using too much AA in low res sprites which can have a muddying effect, but I do question why a single pixel of anti-aliasing used to define a shape or curve that would otherwise be impossible at a given resolution can't be considered part of a cluster? A sub-pixel cluster if you like.

Looking through the examples posted in this thread, in particular Cure's, I have to say I prefer the befores to the afters in most cases when viewed at native resolution.  It really seems to me that eliminating the use of single pixels is most beneficial when viewing a piece at a non-native resolution. Given that screen resolutions are becoming higher and higher I can see the value in that, particularly for game art that might be ported to multiple devices with different screen resolutions, but for pieces that serve no functional purpose I question the necessity, and even the validity, of avoiding single pixels.

[rikfuzz]

Seems to cause more problems than it solves (especially round here where the pixel art is already very high calibre).  It looks particularly arbitrary that diagonals have to be double-thick, where other angles don't.  I guess I 'see' lines as a continuous cluster, even though they're broken by diagonals when at 45º or used in curves. 

Still, definitely useful to see where it does improve things, I'm definitely bad for over AAing, and lots of speckles always harms pixel art.

[Pix3M]

... but I do question why a single pixel of anti-aliasing used to define a shape or curve that would otherwise be impossible at a given resolution can't be considered part of a cluster?

I just tell people that we pay more attention to the pixels when they are bigger, and less attention to how everything meshes together into a whole.

[Faceless]

... but I do question why a single pixel of anti-aliasing used to define a shape or curve that would otherwise be impossible at a given resolution can't be considered part of a cluster?

I just tell people that we pay more attention to the pixels when they are bigger, and less attention to how everything meshes together into a whole.

True enough, but I see heavy use of 2x2 pixel squares in Helm's star girl wip, and that is effectively a bigger pixel, but that apparently counts as a healthy cluster by his definition. I'd contend that two diagonal pixels with anti-aliasing to fill the 2x2 square would in most cases look more natural at any resolution than a solid colour 2x2 square. It's particular noticeable in the rib area. Also, I'd say in his effort to avoid using single pixel diagonals he's created more noticeable banding on her waist area, above her hips. Particularly on the left side of the image. It still looks great as a whole, but I'm not seeing how it is improved by a refusal to use single pixels or single pixel diagonal lines. Honestly some of the finished areas kind of look like the second last step in a progress gif before the anti-aliasing is applied.

Another thing I want to bring up is the indents in the door in Cure's mockup. I'd argue that their entire structure (2x2 square hugged by a 3x1 reverse L) is perceived by the eye as one 3x3 square cluster with the shade of the door in two corners acting as single pixel anti-aliasing to make it appear more unified at native res. As soon as you zoom in those areas kind of fall apart. I absolutely think that those indents would look much better when upscaled if they used an extra shade to AA the square corners.

I guess what I'm getting at is I don't think a cluster should always be defined as a group of pixels of the same shade, but rather as a group of pixels that are read as one clump.

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Edit:
Here's an example of an edit I made (top) to a sprite Slym made that I think illustrates my point about single pixels appearing to be part of a cluster of surrounding pixels that still hold up once upscaled:



Somewhat ironically the edits I made are mostly in line with the principles outlined in this thread before I had even encountered the concept so I seem to have been naturally incorporating it into my work for some time without concious knowledge of what clusters were in pixel terms. The only real change I think I would make after reading this thread is to make the two pixels standing vertically directly above his eye the same shade rather than two.

[Ai]

I guess what I'm getting at is I don't think a cluster should always be defined as a group of pixels of the same shade, but rather as a group of pixels that are read as one clump.

That has pretty much been my definition for a long time: a cluster is a stack of clusters 1-or-more high (usually with brightness increasing as you go up the stack). Inkscape's Trace Bitmap function also implements an algorithm based on this idea and creates highly coherent results.

IME this makes thinking about volume/silhouettes pretty easy. I've never figured out a way to explain it properly that I was happy with, though.

Edit:
Here's an example of an edit I made (top) to a sprite Slym made that I think illustrates my point about single pixels appearing to be part of a cluster of surrounding pixels that still hold up once upscaled:

Yeah, going by the hair, we're on the same page here.
I'd say your edit needs more 'shape flavour' contrast, though (everything seems pretty rounded, whereas there was some round/sharp variation in the original)

[Ryumaru]

Here is my humble contribution to the thread, I hope you don't mind a cross post with my project.



The large rock structure should follow all the rules, the smaller one uses single pixels where I deemed necessary, or just plain wanted them there, and the broken architectural structure is traditional pixel art methods. As a bonus, the main character sprite in the traditional garb should only have single pixels in 45 degree lines. The raven cloaked figures use single pixels relatively sparingly for details or to indicate texture.

To me, the middle ground seems to work the best. If it is convenient, arrange your clusters to have no single pixels, it allows you to have that puzzle fitting power (TM) in some areas, while you still have the freedom to indicate smaller forms or rounded edges with single pixel AA. I like the challenge it brings of thinking of clusters in a different light, and forces me to make choices that I otherwise would have just washed an area in singular AA. Where I don't like it is when I have a clear idea of what I want a form to do, or how I want to make a small area of pixels sing in a certain manner, and the rule is prohibitive. I still am very pro dithering and pro AA, but this has definitely changed how I work with flatter and more planar areas.

[Azuyre]

Decided to try this out by pixeling a plant monster I posted in the sketch thread.


I don't think I have any stray pixels but I did have to use a few 45° connections to get the outline.
Spoiler: Original Sketch

[Basketcase]

I'm loving the results I'm seeing in this thread.

I haven't pixeled much in a while, but this prompted me to try something:

[Helm]

24 megabyte warni-... I guess it's too late now.

I wanted to animate a few bits, but that's as much as I can do for it now. I learned a lot about how photoshop does animation stuff, for this. I'm honestly pretty surprised all those hue shifts fit in a 256 color palette (even with dithering on).

[Mr. Fahrenheit]

Really cool helm!

I can't help but feel that on some of the smaller detailed things using some aa and single pixel would've increased the readability  . The hands mainly.

Awesome picture though and I always love the subtle animations you use on some of your pictures. Speaking of the animation, did you stick to the no single pixel rule as you animated as well or did you erase the extra pixel if it intersected with something?