Gold and Gemstones

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https://youtu.be/htxBTsn_Zhc

Hi. You want to know how to paint jewelry.

So, to do this nicely, it’s good to know a few things about materials.
Metallic- The light only reflects. 100% gloss. Have a colored reflection.
A dielectric material is literally anything that isn’t metal so yeah, everything, almost, except metal.
Dielectric- Some light bounces off, other light is refracted and scattered around.
So, to explain what this means. When the light hits any object, some light will bounce off and we don’t see it on the object. It’s gone somewhere else. If we bring another object in close proximity, we can catch this bounce light. The light that doesn’t bounce off the object goes inside it and refracts, meaning it bounces around, and in doing so it illuminates those parts of the object so that we can now see they are in light.


Metal absorbs all the refracted light. Basically it’s as if the light that goes inside the metal vanishes. Metal doesn’t light up when you put a light on it, it only reflects stuff.
When painting a dielectric material, the faces that are receiving the light are bright. When painting metal, the faces that reflect the light into the viewer’s eyes are bright, meaning that the bright spot will move when you move.
In short, metals look bright where they reflect light while other materials are bright where they are touched by light.
Of course, since dielectric materials are literally everything that isn’t metal, this includes reflective stuff too, but nothing except metal will be purely reflective. Metal too can look less metallic when it gets mixed up with, for example dust or when it gets rusty.
Anyway, it’s important to take materials seriously so you don’t paint everything like it’s made of plastic .

Let’s start with gold.
Gold is generally smooth, undamaged, with clear reflections and, because it’s a metal, it has a colored reflection…

Now, I’m no science expert, but the way I understand it is that when gold reflects light, this light becomes a bit more warm in color… not enough to be noticeable, unless you have two pieces of gold close to each other in a way that makes light bounce many times from one to another. Every time the light bounces it changes color and we get an orange glow effect. It’s quite noticeable inside of, say, a gold bowl. And then of course, if you look at your reflection in a piece of gold, it’ll obviously be yellow and also darker than reality. Gold is darker than, for example silver. Silver is also more shinny than gold meaning the same highlight will shine brighter on silver and the reflections you see on it will be slightly brighter too.


Gems. Now gems vary a lot, all the way from rocks to diamonds. What they mostly have in common is that they’re shinny. What this means is that we can take any average looking rock, polish it, add a layer of gloss and it should look convincingly enough like a gem.

Other gems are transparent, like colorful waterdrops or semi-transparent. Just like when dealing with liquid, the brightness will not happen where the light first touches the thing, but rather, where the light stops. So basically, on the opposite side of the light source.

Now, there’s one more type of gems which are transparent and they also have these faces everywhere inside them looking all extremely complicated. Now, obviously I won’t recommend you try to understand how the light travels inside these things and how and why it does what it does. I’ll just simplify it for you… here’s what you should know: Gems don’t look muddy or organic. This means that most of your usual painting brushes won’t work on them, it’s better to work with special brushes and selections. Faces usually have a flat color, so don’t waste time with gradients, maybe only use gradients for the largest faces. Gems can be pretty dark where they’re not bright. Most gems have only one color so they’re not that complicated. Diamonds mainly can have these random rainbow-colored faces but the effect isn’t too strong so don’t overdo it.

Now, with that in mind, let’s jump into an example and decorate this snake.
I start by drawing in the silhouette of the jewelry. Now, you can choose to do this like I did or you can make a detailed sketch of the jewelry you want before blocking it in. In this case I felt pretty confident to jump straight in. Next I’ll use a Layer in the Add Glow mode to paint in the lights. I will enable color mixing with running color and make sure my “amount of color” here is set to zero, this way I can blend and make some of the edges of the light smooth to describe some geometry. Next I’ll have another layer set to multiply and I’ll paint in some shadows in tight areas where the ambient light gets occluded and where the gold may be reflecting something dark like the snake’s skin.

Now, here’s a very important thing, the shadow areas and the light areas should never mix. Keep this in mind that more often than not, direct light will never touch an area of ambient occlusion, why, well, simply because if it did, that area would no longer be dark. The direct light overpowers everything it touches. Ambient occlusion can happen only in the absence of direct light, so it happens in areas of ambient light where the light gradually gets more and more obstructed.

In other words, imagine you are out in a dark field and the moon is casting your shadow onto the earth. Now, you take out and turn on your torch light and point it at your shadow. Is your shadow going to compete with this new direct light source or is it going to get completely obliterated?
It’s good to remember that in painting, light and shadow aren’t competing forces. Shadows are nothing but the absence of light. And so, a shadow will never darken a light.
Now, value (also called brightness) is not the only reason you shouldn’t get your lit areas and your dark, occluded areas mixed up. The other reason is that the transition from the darkest shadow to the brightest light will also imply changes in hue and saturation.

Now, there’s no standard way in art to measure the precise color of an object… because that color will always depend on the light it receives. Yeah, it felt weird the first time I realized I don’t actually know what color ANYTHING is… because there’s no way to perceive color without light.
… So, anyway, if you hear me talk about local color in future videos, it’s not because I know something you don’t. I’m simply saying “Local color” to refer to the color of an object where it gets revealed the most clearly, usually in ambient light. I could just say “the object’s color” but that’s a bit vague and… hey, terminology might help you when you watch tutorials by other artists.

ANyway, back to the example. I next made a layer underneath the gold and painted in some more of this ambient occlusion thing using another multiply layer.
Next I go back to the gold and give it another add glow layer but this time I use it to paint with a dark blue color which creates this soft blue light on the gold. I’m painting something like a reflection of the sky.

Lastly to make the gold more convincing I create a color layer and add come orange accents in areas where the gold could be reflecting itself back and forth like I mentioned earlier.

Now, I want you to realize one thing- my gold is not perfect. Not every area that should receive direct light is lit, the reflexions are not consistent and not every edge describes geometry. Leaving this in a rough state is somewhat intentional so you can see that you don’t need a render engine running in your mind so you can paint believable gold in a way that nobody will think twice about what this is… and also in a way that anyone can easily replicate.
If you try following my steps, even with basic skills, your result should look quite close to mine. If you do everything like I showed in this video but it ends up looking bad, the only explanation pretty much is that you have a problem understanding the 3D nature of the subject you’re painting, in other words, when you shade your image, you have a hard time deciding which surfaces should be receiving direct light and which ones shouldn’t and how much light should a surface receive based on how its angle is facing compared to the light source.
I’ll find some helpful video on the basics of understanding 3d shapes when drawing and I’ll link it in the description over on Youtube.

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