Pixels And Art Glossary

[0xDB]

Everyone's favorite term added. Cluster! I took the liberty to broaden the originally proposed definition from "equally colored connected pixels" to "perceptually connected" and in the same breath added super-cluster, sub-cluster and fragment as terms for the mind to think about when pondering how to shape, place and combine clusters. An interesting observation is that the relationship between any two neighboring (sub)clusters, both in shape and value, has an effect on the implied orientation and direction of both clusters.

Cluster

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A patch of perceptually connected pixels which
are part of the description of a shape, volume
or texture or any other element.

A cluster may be thought of as a fragment of
any element, as a sample of anything, as seen
by the eye or as imagined.

Shaping and shading a cluster gives direction
and orientation to the cluster itself which
also serves to give direction and orientation
to the element which the cluster aims to help
define.

Shadow and light on a cluster can be thought
of as individual (sub)clusters as well. Single,
perceptually separated pixels are not clusters
by definition.
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further reading:
http://wayofthepixel.net/index.php?topic=8110.0 - Ramblethread
http://wayofthepixel.net/index.php?topic=15566.0 - 1st Cluster Study Thread
http://wayofthepixel.net/index.php?topic=15018.0 - 2nd Cluster Study Thread
(just search for "cluster" on this board... there are a few more )
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[Gil]

I like that definition, it's a little broader and encompasses more pixel art.

Maybe we should eventually use all this for a wiki.

[Ai]

Making some kind of site from it sounds good.

Personally, I don't have the same trust in wikis that I once did -- in particular, my impression is that the more room for subjectiveness in the topic, the worse a wiki functions. I think a site whose content is generated from a github repo curated by a small team, that of course anyone can submit pull requests to, is a model that would do better at creating a trustworthy resource of consistent quality.

[wzl]

i actually like the forum approach, as it doesnt disconnect content from the discussion. I was a member of the gpwiki before, and that just fell apart, because it split the community up. Not a fan of that.
And with the tagging system i suppose we can have a sort of overview or index page for tutorials and other articles like that, which would be kinda cool.

[Gil]

I like Ai's idea of a curated github.

[0xDB]

Updated op with a bunch of links (still lots of stubs/bullet points left to fill with details).

Changed the "Color" entry to emphasize that the concepts described in there are of emotional nature and not meant to describe the physical process of any color mixing theory nor the scientific property of color temperature.

Added entry for Color Gradient, Color Ramp, Color Shift.

[Ai]

* Are those supposed to all be synonyms? In that case, I guess Hue Shifting is being covered separately, perhaps in the Hue entry?

* I assume you are aware that there are other color spaces that can be usefully used for calculating gradients (HSL, LAB, LCH), as well as linear RGB versus sRGB, and just left them out to keep things simple?

* The term 'lightness' is associated with HSL channel L, which may be confusing in this context. I believe you used the term 'brightness' (which has no association with any particular colorspace AFAIK) in an earlier entry.

[0xDB]

* Are those supposed to all be synonyms? In that case, I guess Hue Shifting is being covered separately, perhaps in the Hue entry?

There will also be an extra entry for Ramps where I will give examples how the same color can be re-used in different Gradients and possibly arrange the Ramps on a 2D grid with intersections. To be honest, I don't see much of a conceptual/technical difference between saying "the color shifts" or "the hue shifts". Hue shifts for creating cheap effects are overused imo and in most cases don't make any sense at all (but well... maybe there should be an extra entry for them... without my personal judgement about it). Ramp,Gradient,Shift... conceptually all the same.

* I assume you are aware that there are other color spaces that can be usefully used for calculating gradients (HSL, LAB, LCH), as well as linear RGB versus sRGB, and just left them out to keep things simple?

Hence the wording "Primary" and "can be" as opposed to something like "Eligible properties for change are...". I pay attention to phrasing my stuff carefully and packing as much information as possible into each and every word. You can make up any number of derived/calculated secondary properties from the plain RGB model and use those to create gradients. Can also just make gradients by feeling and picking arbitrary colors instead of calculating the changes and having them follow any continuous mathematical function.

Always a struggle finding a balance between simplicity and complexity, especially since most artists are not very likely to also have an affinity to math and technology.

* The term 'lightness' is associated with HSL channel L, which may be confusing in this context. I believe you used the term 'brightness' (which has no association with any particular colorspace AFAIK) in an earlier entry.

It is used here in the sense of 'value as lightness' as described in the entry for Brightness/Lightness/Value. It appears to be the same sense as the L in HSL. Mixing pure color with white increases the Lightness (creates Tints), mixing with black decreases Lightness (creates Shades).

[edit: Actually the L in HSL is NOT "Lightness As Value" but rather some arbitrary Brightness which varies greatly with different hues in that model.]

[Ai]

* Are those supposed to all be synonyms? In that case, I guess Hue Shifting is being covered separately, perhaps in the Hue entry?

There will also be an extra entry for Ramps where I will give examples how the same color can be re-used in different Gradients and possibly arrange the Ramps on a 2D grid with intersections. To be honest, I don't see much of a conceptual/technical difference between saying "the color shifts" or "the hue shifts". Hue shifts for creating cheap effects are overused imo and in most cases don't make any sense at all

Eh, making the shadow a complementary color to the highlight adds contrast and shadow/light separation (it can add contrast while preserving lightness, which is a valuable tool)
This is a classical technique used a lot in historic paintings, not only pixel art.
Certain combos appear more natural than others (yellow light+blue shadow is pretty much natural sunlight, as long as you don't overdo it), but IMO unnaturalness occurs mostly when you make different arbitrary hue adjustments on different ramps, rather than having a general trend of shadows become X-er, lights become Y-er across most ramps. I guess that idea of unifying would fit naturally into an entry on Ramps.

My impression is that here you are covering the concept of interpolating a discrete function, and provide hue as one demo. This does not, IMO, imply the 'hue contrast for additional readability/pop' theory that is behind hue shifting.

Hence the wording "Primary" and "can be" as opposed to something like "Eligible properties for change are...". I pay attention to phrasing my stuff carefully and packing as much information as possible into each and every word.

Okay, my mistake. I agree that R` G` B` and H S V are commonly recognized metrics, regardless of any other opinion I may have of them.

Can also just make gradients by feeling and picking arbitrary colors instead of calculating the changes and having them follow any continuous mathematical function.

Well, yes. For shorter ramps (say <=5), that's quite sensible. For longer ramps, calculating a ramp (which is easy and involves no math, with a decent palette editor) and then adjusting it by hand may produce more consistent results with much less effort.

* The term 'lightness' is associated with HSL channel L, which may be confusing in this context. I believe you used the term 'brightness' (which has no association with any particular colorspace AFAIK) in an earlier entry.

It is used here in the sense of 'value as lightness' as described in the entry for Brightness/Lightness/Value. It appears to be the same sense as the L in HSL. Mixing pure color with white increases the Lightness (creates Tints), mixing with black descreases Lightness (creates Shades).
[/quote]
This is probably just me being pedantic then.... HSL L (or HSV V) is kind of like Lightness. except that Lightness goes up and down as H and S values change, with same L value. So, only if you don't look at it too hard? I think they are intended to do the same thing but in practice do significantly different things.

[0xDB]

Eh, making the shadow a complementary color to the highlight adds contrast and shadow/light separation (it can add contrast while preserving lightness, which is a valuable tool)
This is a classical technique used a lot in historic paintings, not only pixel art.
Certain combos appear more natural than others (yellow light+blue shadow is pretty much natural sunlight, as long as you don't overdo it), but IMO unnaturalness occurs mostly when you make different arbitrary hue adjustments on different ramps, rather than having a general trend of shadows become X-er, lights become Y-er across most ramps. I guess that idea of unifying would fit naturally into an entry on Ramps.

My impression is that here you are covering the concept of interpolating a discrete function, and provide hue as one demo. This does not, IMO, imply the 'hue contrast for additional readability/pop' theory that is behind hue shifting.

There definitely needs to be an entry for Hue Shifting then for the cases where it's not a cheap unnatural effect. The one you describe is also shown in the video I linked to under the Color entry. Emphasizing shadow with a complementary color is in fact an extension of that natural perceptual illusion that the shadow appears to be colored to our eyes in reality when it is in fact still a shade of gray. That's not what I mean by cheap effect. It only feels cheap when the shift is arbitrary(I even did that myself more than once). I was not aware that Hue Shifting specifically refers only to the non-arbitrary appearance derived from the naturally occurring optical illusion. I see a lot of non-sensical hue shifts in Pixel Art which looks kind of funky/fresh/psychadelic but also starts to feel really cheap and overused. So, you're saying Color Shift is arbitrary? Hue Shift refers to one specific optical illusion observable in reality?

This is probably just me being pedantic then.... HSL L (or HSV V) is kind of like Lightness. except that Lightness goes up and down as H and S values change, with same L value. So, only if you don't look at it too hard? I think they are intended to do the same thing but in practice do significantly different things.

Nothing wrong with being pedantic, I just do not see how there could be any confusion there. Lightness is not immediately available as a primary property in HSV/HSB. Value there means something else, see Brightness/Lightness/Value. HSL is something completely different from HSV/HSB and Brightness in HSB isn't even "brightness" in the common sense. There the B is equal to V and it's more related to the common sense of "saturation" which in turn though is different from the sense that S, Saturation has in HSV/B. I believe people will always find this confusing no matter what because there is no consistency in these terms across different color models and no consistency with their common sense interpretation either. Lightness in the sense I use it there seems fully synchronized with what it means to describe.