Rendering Discussion: "Edges" Tips and Tricks

[Elwell]

I wrote this up as part of a reply to this thread, but I thought it was worth reposting here.

Edge basics 101:
There is a scale of edges, just as there is a scale of values. It goes from hard>firm>soft>lost. Just as with value, you can use the whole scale in one picture or just a piece of it. The careful manipulation of edges is one of the most overlooked, but most important, tools an artist can use to create form, atmosphere, and believability.

In general, edges are:
Harder in the light, softer in the shadow
Harder in bright light, softer in dim light
Harder in focused light, softer in diffused light
Harder in the foreground, softer in the background
Harder on smooth forms, softer on textured forms
Harder on hard forms, softer on soft forms (Duh, but really)
Harder on flat forms, softer on rounded forms
Harder on thin forms, softer on thick forms
Harder on still forms, softer on forms in motion (on moving forms they are harder on the leading edge and softer on the trailing edge)
Harder at the center of interest, softer as you move away

The above are additive. So a kitten, far away, in the dark, would be really soft.

Of course, any of these guidelines can be ignored/modified for pictorial effect.

[Ive]

Me too,
there's this excellent little tut Gregpro did though:

[EtaCarinae]

Dear Elwell,
I'm just rewriting these points and feel like I don't really understand some of the latter ones. I.e;

Harder on hard forms, softer on soft forms
Can you give an example of this? I'm confused. Lead would be a hard form with a softness to it's edges, but jelly (or jello) would be soft with a hard edge. Or am I getting this confused with spectoral highlights?
Harder on flat forms, softer on rounded forms
Like a cardboard box compared with a ball? A D20 compared with a marble?
Harder on thin forms, softer on thick forms
Like a thin straw compared with a thick pipe or barrel?

Also (and this is going to sound stupid but...) what is the definition of an edge? Would it be safe to describe an edge as,
'A transition caused by either light hitting adjacent surfaces of a single object or adjacent overlapping objects/surfaces'?

I know this was posted sometime ago so anyone want to have a go at it?
Regards,
EtaCarinae

[Elwell]

Harder on hard forms, softer on soft forms
Can you give an example of this? I'm confused. Lead would be a hard form with a softness to it's edges, but jelly (or jello) would be soft with a hard edge. Or am I getting this confused with spectoral highlights?

If you had to show the difference between lead and, say, steel, you could use a softer edge on the lead because of it's duller surface texture. Jello doesn't necessarily look different than colored glass or plastic, but you might want to soften it's edges to convey the fact that it jiggles.
In painting the figure, areas where bone is close to the surface (nose, collarbones, kneecaps, etc) are handled with harder edges than fleshier forms.

Harder on flat forms, softer on rounded forms
Like a cardboard box compared with a ball? A D20 compared with a marble?
Harder on thin forms, softer on thick forms
Like a thin straw compared with a thick pipe or barrel?

Exactly. In both cases it has to do with how "fast" the form turns.

Also (and this is going to sound stupid but...) what is the definition of an edge? Would it be safe to describe an edge as,
'A transition caused by either light hitting adjacent surfaces of a single object or adjacent overlapping objects/surfaces'?

Not bad. Painters tend to use the word edge to mean both the physical boundaries of actual objects and any place where two "pieces of paint" meet. Look at the plane diagram in Greg Pro's paintover. Wherever you have a plane change, you have an edge.

Remember, these aren't hard and fast rules! If something has to be harder or softer than it "should" be to do it's job in the picture, good! The main point is to think about and design your edges with as much care as you would put into any other aspect.

[Longxiang]

I'm new to the concept of painting in layers. I'm more used to doing something in pencil, then finishing all the edges with ink.

When you paint, how many layers do you do, and at what layer will the edges appear? Especially the hard edges. At the end?

If you don't have any solid boundaries while you're working, how do you keep a sense of the shapes of things?

[andyhunt]

When you paint, how many layers do you do, and at what layer will the edges appear? Especially the hard edges. At the end?

If you don't have any solid boundaries while you're working, how do you keep a sense of the shapes of things?

Your first question has no answer. It depends entirely on the artist and the subject.

Your second question seems to be a bit of a misunderstanding. You can have solid boundaries from the very beginning. This tutorial is simply showing the general firmness that the edges of a particular form should have in a given light, focus, or distance. It is this hierarchy of edges that can create a true sense of visual depth in an image.

[kelly x]

Thanks and someone directed me to this page for hard and soft edges... I will put it into use and makes sense -- but will have to cut and paste... kelly

[Arteater]

Thanks for taking the time to help out, I don't think many people know about how much priceless info you can gain from this site.

[J Wilson]

Just one of the reasons why I love these forums. There is always some nugget of condensed knowledge lurking I think a lot of this is stuff I've often used to various degrees, but never really stopped to think through. Having someone point it out really makes a difference in being aware and giving it a little extra thought. Thanks!

[Moikey]

Elwell is the word for god, on the lips and hearts of all artists!

[Elwell]

More discussion of edges in this thread.

[Elsevilla]

ive always asked this myself tons of times, nobody had told me this thanxs elwell and ive

[TMG]

So if edges are softer on textured forms, and harder in bright light, how would one depict holy kitty?

Subject A, holy kitty:

[Elwell]

I know it's somewhat a facetious question, but...
What you have there is an example of halation, which occurs on strongly textured or hairy/fuzzy surfaces in rim and backlighting. Notice how the outside contours are harder in the lit than in the shadow areas. Also, photography exaggerates these effects. The lights wouldn't appear nearly as blown out in real life, and the individual hairs and whiskers wouldn't be as distinct.

[Aaron Death]

Thanks elwell, very useful information