Just wondering...

because just black wouldn't show any changes in the spec value's.

The Happy Friar wrote:

because just black wouldn't show any changes in the spec value's.

I guess he´s asking why are they colored and not grayscale.

Isn't that to give more of a different colour tone to the highlighted parts of the texture?

See Modwiki: Specular maps.

As far as I know there isn't a requirement for it to be colored but with the right tweaking of the color values you can really bring out the color of a diffusemap with a high quality specularmap. In my opinion, you can make a texture look better with just a high quality specular than with just a really good normalmap.

Bittoman wrote:

As far as I know there isn't a requirement for it to be colored but with the right tweaking of the color values you can really bring out the color of a diffusemap with a high quality specularmap. In my opinion, you can make a texture look better with just a high quality specular than with just a really good normalmap.

See Halo 1, for instance.

Ok. Thanks.

Ok, but does anyone know the real reason for the colors involved? It's not really intuitive, but there seems to be an inversion of the diffuse that seems popular. The specular on blood for example has a teal cast... any hints?

Let's take a cherub for exemple, "tail" & "wings" got a cool 'blue fly' effect because of speculars.

Speculars define how the diffuse will be at light, if you just put a full white specular on a red diffuse, lighted zones will be white, but if you put a blue specular, lighted zone will be a blueish red...

But that's not so simple, cause specular define the color, but also the level of intensity of it. you can't have a red diffuse turning to a black specular (lighted zones).
More your specular is dark, less diffuse will "shine".

Check out the fist models to see just how important colored spec is. Diffuse is Green and Specular is Purple if I recall correctly.

onu wrote:

Check out the fist models to see just how important colored spec is. Diffuse is Green and Specular is Purple if I recall correctly.

We don't have the same version so, i just checked (D3), and arms in both "berzeker" & "hands" weapons got a pink skin diffuse, but a dark grey/black specular.

Speculars don't need to be the diffuse inverted colors, just the color you choose it to be where it shine.

Quote:

The specular on blood for example has a teal cast... any hints?

Somebody explained that to me as "the specular fighting with the diffuse to produce desaturation in highlights".

The idea is that as the specular contribution grows (towards the center of a highlight), it will "fight" the opposite colours of the diffuse and desaturate the highlight more than a pure white specular contribution would.

Thanks for replies, guys. At first the spec maps appeared to me as basically inverted and tweaked diffuse maps, but I checked them in photoshop and it looks like they're actually totally re-painted, most of the time. Anyhow: Weird, unexpected and quite interesting...

Edit: Typo

Displaced wrote:

it looks like they're actually totally re-painted, most of the time. Anyhow: Weird, unsuspected and quite interesting...

What's so weird about specular maps? I think your question actually is not "why are they colored", but "what are they", right?
In order to produce good specular maps yourself, you should know how they tie in with the lighting model, what they do and why they exist.

http://en.wikipedia.org/wiki/Phong_reflection_model
This wikipedia article is not a good read for artists, maybe someone has a link to a better article. Also, if you happen to have Max or Maya, their tutorials have some good information too.

3DS Max Reference wrote:

Specular mapping is used primarily for special effects such as placing an image in a reflection. The important thing to remember is that, unlike Specular Level or Glossiness mapping, which alter the intensity and location of specular highlights, specular mapping alters the color of specular highlights.

der_ton wrote:

What's so weird about specular maps? I think your question actually is not "why are they colored", but "what are they", right?

No. The question is what it was. I wondered why it wasn't just greyscale, like a heightmap, where white was 100% specularity and black 0%. Yes, I found it weird and unexpected that color should be a part of the equation, as a specular light is a reflection of a light source and that light source's color mixed with the color of the surface reflecting it, or at least that's how it is in the non-virtual world. As the local color of the surface is already given in the diffuse map, I found it kinda weird, but then again I'm an artist, and not a tech wiz... Thanks for the link, anyways!

Lumpengnom wrote:

3DS Max Reference wrote:

Specular mapping is used primarily for special effects such as placing an image in a reflection. The important thing to remember is that, unlike Specular Level or Glossiness mapping, which alter the intensity and location of specular highlights, specular mapping alters the color of specular highlights.

But specular mapping would here translate from Max to game engine as what is usually used for "simple reflection", right? In other words the faking of world reflection on a surface, for instance water, by the use of a flat image of the world reflected? But the D3 engine uses the one map for two things, specular level as well as the color of the highlights? I still don't quite understand why altering the color of the highlights is needed, because it doesn't translate very well to my understanding of the real world, heh...

This is another good link.

http://www.bencloward.com/shaders_skin.shtml

Even if it doesn't happen often, there ARE real world materials that reflect a different color in their specular reflection than in their diffuse. Skin for example, or those modern car paints.

6th Venom wrote:

Speculars define how the diffuse will be at light, if you just put a full white specular on a red diffuse, lighted zones will be white, but if you put a blue specular, lighted zone will be a blueish red...

And why would one want that unless the light source was actually blue? To me that sounds like you can only light a model with a blue spec map with a blue light to make the whole thing look correct in according to it's environment?

6th Venom wrote:

But that's not so simple, cause specular define the color, but also the level of intensity of it. you can't have a red diffuse turning to a black specular (lighted zones).
More your specular is dark, less diffuse will "shine".

Now this I understand, however, and is basically all I expected spec maps to be about from the beginning.