Thanks for the feedback, Ai.
The banding occurs with thin lines rather than lines that are of different thickness.
How so? My 'bad example' was done by imagining myself as a naive pixeler: 'Okay, 1 px line is not thick enough, 2px is too thick..I'll just use 3px bands but overlap them a little'. (ie. an attempt at creating 1.3-1.5px width without any AA available). The result being similar to fig.23, which I consider a thickened line.
But it also applies to faces of any non-huge size AFAICS.
This is due to the looser connections of linked pixels. So adding weight would be one way to prevent it, or by using less linked pixels.
Thanks, this helps me think about linking and binding more..
To me, it looks like the 'e' pixels are binding vertically, taking priority over the diagonal linking. Maybe that's what you mean above. The linking/binding principle doesn't appear to apply directly to larger shapes such as
Key:
e: non-axisbound edge pixel
E: axisbound edge pixel
#: shape impression created by axisbound edge pixels.
Bad: (4 edge pixels with 2-axis alignment)
..E#E.
e*###e
.e###e
..E#E.
Better: (2 edge pixels with 2-axis alignment)
..e*E.
e***#e
.e**#e
...eE.
Better, different solution: (2 edge pixels with 2-axis alignment)
..e**E.
e****#e
.e***E
...ee.
However, in my experience, the 2-axis-aligned pixels
do visually 'bind' across any amount of space found in typical pixel image sizes, creating impressions of rectangles or lines. This is not necessarily "bad" (it's one of the major factors involved in an impression of symmetry imo), but is generally avoided in any strong flow-focused design. (Loomis calls these arrangements 'informal' [flow-focused] and 'formal' [uniformity-focused] respectively).
So thats what I was trying to get at -- how alignments of opposite vertices bind through the shape, not only with immediate neighbours, and this effect is especially hard to avoid because of pixel art's low resolutions.
Like the new visualization, it's very clear. I agree with 0xDB on the value of blending it with the original. Being able to cycle through display modes 'original -> blended -> diagram-only' would probably be instructive.