Comment by skydhash | Hacker News Reader

Comment by skydhash | Hacker News Reader

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> For example, a common device that painters employ is to configure the neighboring regional contrast of a form can be light against dark on one edge and dark against light on the opposing edge.

I'm not fully sure of what you means. If we take the following example, are you talking about the neck and the collar of the girl?

https://i.pinimg.com/originals/ea/70/0b/ea700b6a0b366c13187e...

https://fr.pinterest.com/pin/453596993695189968/

I think the name of the concept is "edge control" (not really original). You can find some explanation here

https://www.youtube.com/watch?v=zpSlGmbUB08

To keep it short, there's no line in reality. So while you can use them when sketching, they are pretty crude, kinda like a piano with only 2 keys. The best thing is edges, meaning the delimitation between two contrasting area. If you're doing grayscale, your areas are values (light and shadow) and it's pretty easy. Once you add color, there's more dimension to play with and it became very difficult (warm and cold color, atmospheric colors, brush stroke that gives the illusion of details,...).

Again, this falls under the things that are easy to explain, but take a while to be able to observe it and longer to reproduce it.

There's a book called "Color and Light" by James Gurney that goes in depth about all of these. There's a lot of parameters that goes inside a brush stroke in a specific area of a painting.

> I'm not fully sure of what you means. If we take the following example, are you talking about the neck and the collar of the girl?

Yes... that's exactly it. It is also described in our teaching material here, (half way down the page):

https://rmit.instructure.com/courses/87565/pages/structural-...

Rembrandt was an avid user of this technique. In his portraits, one little trick he almost always used was to ensure that there was no edge contrast whatsoever in at least one region, usually located near the bottom of the figure. This served to blend the figure into the background and avoid the flat effect that would have happened had he not used it. In class I call this 'edge loss'. An equivalent in drawing is the notion of 'open lines' whereby silhouette lines are deliberately left open at select points.

> I think the name of the concept is "edge control" (not really original). You can find some explanation here.

I am aware of the term 'edge control' though I have not heard it used in this context. I feel that the term is too general to describe what is happening in the (so-called) tone wrap.

To extend the principle, wrap is an important concept in spatial rendering (painting, photography, filmmaking etc) and is a cousin of overlap. Simply... both serve to enhance form.

> To keep it short, there's no line in reality.

True that. I learned a lot about lines from reading about non-photorealistic rendering in 3D. There are some great papers on this subject (below) though I feel there is still work to be done.

Cole, Forrester, et al. "How well do line drawings depict shape?." ACM SIGGRAPH 2009 papers. 2009. 1-9.

Cole, Forrester, et al. "Where do people draw lines?." ACM SIGGRAPH 2008 papers. 2008. 1-11.

I made a stab at summarizing their wisdoms here:

https://rmit.instructure.com/courses/87565/pages/drawing-lin...

> There's a book called "Color and Light" by James Gurney that goes in depth about all of these. There's a lot of parameters that goes inside a brush stroke in a specific area of a painting.

Looking at it now. Any writer who references the Hudson River School is a friend of mine.

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