Speculars, radiosity, etc.

**Beer Baron** · January 14th, 2004, 10:01 AM

Thank you for taking the time to put this together, Prom. Very insightful and helpful. The tennis ball analogy really helped.

Can you recommend any art books that deal with this topic in-depth? Most of the books I've found deal primarily with mixing colors a certain way and not exactly explaining why. I'm mostly looking for something along what you talked about: what our eye can see, the dynamics of light, etc. Might this book be in the 'Science' section?

Color theory is an area that confuses me the most. Your tutorials really help clear away some of the clutter. Thanks.

**Prometheus|ANJ** · January 16th, 2004, 12:24 PM

THeree's some blue on skin too. Frazetta paints it a lot (hips, boobs). Light can also pass right through skin and make it red/orange, you've seen this effect on ears and fingers maybe.
Anyhow, this is just a part of a big tutorial I'm working on. I'll try to cover everything I know in it, including light falloff and stuff. I often fall into the trap of over-volumating with shadows and hilites. When I look at stuff in real life I notice how flat values can be. Sometimes it's just a flat shadow and flat light even though there's lots of bumps and knobs on the surface that would look neat volumated out more.

As for books I don't know of any. Maybe loomis?

**funshark** · February 2nd, 2004, 01:21 PM

wow!
I can't wait to see your big tutorial, Prometheus !!
:jump1:

**Marcatili** · February 24th, 2004, 04:39 AM

Hey Prometheus,
I really appreciate the tutorial as well, although unlike some of the others I didn't find it all self-explanatory necessarily.
Most of it I was ok with once I looked over your diagrams a few times.

I didn't understand the reason for some of the diagram elements, for example where you have the tree which is shadowed by the sun and then a brighter or maybe diffused sun where the tree is not shadowed. I understand the middle diagram where the sun is shadowed because of the strong back light of the sun but not why or how the bottom one worked.
Also, next to that there is a tree with a sun beside it and a blue line- does the blue line indicate a range of something or is it a cross-section? I wasn't sure...

Like I said, I understood most of it but I suppose the other main thing is I'm the kind of person that needs to know why things are, not just that they are. Or maybe I'm just a lunk-head...

anyway, thanks for the great tutorial, I do think it requires a basic level of understanding light and colour theory but that's fine

thanks again

**naz** · February 27th, 2004, 03:35 PM

great illustrations and especially thanks for your "How I paint in Photoshop FAQ", together they really give a great insight!

on the illustrations sheet, the section with the ambience right/wrong, I understand now what it means, but first it was not imminently clear to me.

thanks again for sharing!

**gekitsu** · February 27th, 2004, 06:09 PM

expat: the three illos with the sun and the tree basically read like that:

since sky and sun are of significantly higher value than the tree, and the eye/mind tends to simplify what you see in simple value patterns with a very narrow value scale, you will never see something like the topmost illustration.

your eyes would either focus on the foreground values (the tree), but this would knock both sky and sun "out of range", as seen in the lower illustration.

if you focus on the background color (sky), you will see the difference in value between sky and sun better, because you adjusted your value key to this particular part of the value scale. the tree, however will be knocked out of range then and appear as a dark silhouette, as seen in the middle illo.

**Groover McNab** · March 30th, 2004, 12:23 PM

This is great! Thank you!

**Grooveholmes** · April 4th, 2004, 02:20 PM

Ah yes...

Some of the best golden gold ever to be gold.

**sandu22** · April 7th, 2004, 06:54 PM

About the skin.. not only Franzetta.. also Boris , even Dali..anyway is a good trick. :chug:

**AmadorL** · April 26th, 2004, 07:38 PM

Hey Dude when are ya going to get to those unfinished tutorials on your website? looking forward to seeing them.

-A

**fabyan4u** · May 6th, 2004, 04:07 AM

:evilbat: it is the most explicit thing i've ever sow.now i understand the color combination thing

**Kress** · May 26th, 2004, 12:34 PM

Prom, I was just thinking to myself, oh man, I better get to some practicing, I'm getting way sloppy. And lo and behold, here you come with this packet of goldness. Awesome.
I've been painting bilites by picking the light color and slapping it right on top of things. How brutish

So uhh, how about some more matte/flat material information???
Thanks so much for posting this. Hopefully I'll be able to apply it.

**herbesahne** · July 14th, 2004, 02:27 PM

It's a really interesting topic, I was wondering if there are books on this subject ? And also do you think it's a good idea to study light/colors with a 3d program (but then again wich renderer..)

**RefrigeratorCo** · August 11th, 2004, 07:43 PM

You posted some interesting stuff man but I think I need some words to go along with the pictures.

**Pesmerga** · September 30th, 2004, 11:10 AM

Awesome tutorial! but your hand writting is terrible, lol.

This may sound pretty stupid, but... I'm not sure I understand this one:

And about your reflecting sleeve... I'm wondering:

That red in the lower part... is that your cam reflecting it?

**Gator** · October 7th, 2004, 01:23 PM

that is a really useful explanation on how light bounces around!

From what I understood, the red and green dots show where Prometheus was pulling the sleeve with his fingers. He used a cotton sleeve to show how a coarse fabric also has specular properties (in this case, bouncing off light emanating from the screen). At least thats what I think it is!

Though I do have my doubts on that first picture you posted, Pesmerga. I don't fully understand that one either.

**At_the_Gates** · October 12th, 2004, 07:46 PM

I think that the first pic shows how the sky (or blue things) reflects on
different surfaces/colors... it kinda makes the skin a bit blue, but when
you have some black clothes, it kinda "sucks" in the color. heh...

**hamsterdance** · October 13th, 2004, 10:49 PM

Thank you for this tutorial. This was very helpful for me.

**IvanDashSmith** · November 11th, 2004, 04:32 PM

Great stuff Prometheus. I downloaded this off of your website some time early in the summer, and made it my desktop which helped a lot in my illustration class. That and a lot of your work I showed my teacher inspired him to assign a digital painting. Keep slappin down the knowledge, and update your website dood.

**nonie** · January 10th, 2005, 12:12 AM

This thing made me have one of those "oh my god, duh" moments. The little "can't get darker" note - suddenly radiosity makes just a little more sense. Thanks for posting it, Prometheus

**Judy Warner** · July 30th, 2005, 05:30 AM

is there any way to see the pictures on this thread--all I see are the dreaded x's.. ????? Judy

**Elwell** · July 30th, 2005, 08:14 AM

Originally Posted by Judy Warner

is there any way to see the pictures on this thread--all I see are the dreaded x's.. ????? Judy

http://www.itchstudios.com/psg/art_tut.htm

**Judy Warner** · July 31st, 2005, 05:10 AM

lots of very, very good info now that I can see the pictures! Judy W

**Farvus** · September 1st, 2006, 07:04 PM

well, if you have the color from the monitor, which appears to be cold white, and the color of the sleeve which is dark brown-ish, then you colorpick the sleeve color, drag up the blue slider a bit, and the green and red just a tiny bit.

Arghhh. Why didn't I thought of using sliders before

. I was recently painting a lot with natural media and using only primary colours. In Photoshop there are CMYK sliders so I could learn a lot by using these.

Thanks for writing this Prometheus !!!

Farv

**tanz** · February 14th, 2007, 11:39 AM

the pics gone missing...

**Elwell** · February 14th, 2007, 01:15 PM

Originally Posted by tanz

the pics gone missing...

http://www.conceptart.org/forums/sho...8&postcount=52

**amit3d** · November 6th, 2007, 09:37 AM

Really a very good link. Thank you.

**626elemental** · December 17th, 2007, 05:29 PM

Amazing! The best tutorial I've seen in years!

**George Abraham** · June 1st, 2009, 06:35 AM

I think it could be a good idea to build a material library in either visual or written reference to build some sort of databank about how different materials behave in light.

I have scanned the net for something that other artists have done perhaps but I couldn't find any.

Maybe one of the fundi's here could sell off a collection of sphere's and cubes made from different materials with notes on what effects they are paying attention to.

Some 3D apps have nice libraries but I feel a painted out version will be much better and there’s so much effects to explore.

**Natalyah44** · August 28th, 2009, 04:17 AM

Originally Posted by cateaic

That was an awesome tutorial..it helped alot!
I dont think we can get enough skin tone tutorials. In fact, if anyone here has any other skin tone tutorials please share!!! =)

Glad to read such a nice piece of information.
This is exciting news.

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