Another form of gradation is the sphere. Think of the sphere as a circular-shaped gradation, with a very similar technique as normal gradations. The first thing you need to do is to decide where the light is coming from, as that determines where the highlights and shadows are.

As usual, start with the base color, here it is Grass Green. The highlight here is centered, to show the basic, simple shape. I like to draw a very light cicular stroke around the highlight, just to define the exact location of the highlight, and then make the color darker as I go to the edges. You'll notice that I take the color almost all the way in, with a small area of paper white in the center.

On the right, I've used White to fill in the highlight and smooth out the color, all the way out to the edge.

The final step is to add some Black. This is optional, or course, since it is quite dramatic. You could also use a dark green to add the additional shading on the edges. It's up to you, depending on how dramatic or light you want the color to be.

In this example, I used a second color to make the sphere more interesting. On the left, I started with the base color (Crimson Lake) and made the basic gradation, with a larger highlight in the center. Then, on the right, I added a gradation of Sunburst Yellow as a secondary color, still leaving the absolute center of the circle page white.

The third step is to fill in the highlight with White. Be sure to blend the White all the way out to near the edges to completely blend all the colors together. Plus, you'll notice that the White smooths out some of the roughness and darkness that was from Step 2.

Then, on the right, I added some Tuscan Red to add some richness to the edges, giving the sphere a more three-dimensional look. Use light, gentle strokes to slowly blend in the gradation of the dark red. It takes a very light touch on the pencil.

This time, we're going to make a shiny ball with a highlight from above and the left. The more shiny you want the object, the smaller and harder you need to make the highlight. When a highlight is wider and smoother, the surface tends to look more dull.

Start with the Mulberry base color on the left, leaving a smaller highlight with a harder edge. In Step 2 on the right, I fill in the highlight with White, again blending the White far out into the base color to blend them well.

To make it interesting, I add a secondary color as shading, which is Ultramarine Blue. Adding complemenatry colors always makes your drawings more interesting and life-like. The blue was added on top as a simple gradation, solid at the edges, and getting lighter and lighter towards the center.

To really add drama, on the right I add on a final gradation of Black. This really adds depth to the sphere. It may look too dark here, but that is because it is on a pure white page. If it is surrounded by other dark colors in a full drawing, it will look just right.

Here is another example of a sphere or gem. Start with a base color of Chartreuese, and then fill in the highlight with White.

Add some shading with Grass Green to start to bring out the shape. Then, on the right, use Black to give the edges more shape.

It still looks a little thin or flat, so I start with adding a gradation of Deco Aqua on the left. It smoothed out the colors, but it didn't add the darker color that I wanted. So, on the right I blended in some Non-Photo Blue to give the sphere some more substance. Yes, I prefer richer colors -- drawings with "guts."

A popular sphere technique is a glass ball or jewel. The characteristics of this are sharp, strong highlights combined with strong, defined shadows. Here, I started with a base color of Sunburst Yellow, and then I filled in the highlight with White. Many times, it is best to fill in the highlights as soon as possible, because that will keep them clean, and not contaminated by smudges of other colors.

I could put the shadow oppopsite the highlight, but it is also a good technique to have a "reverse shadow," where the shadow is on the same side as the highlight. This depicts a round glass ball, like an eye, where the edge of what is holding the glass ball, like a mount or eye socket, actually casts a shadow on the side where the light is coming from. If the shadow is on the opposite side of the highlight, that would suggest a flat-bottomed glass dome, rather than a ball.

So, I put a very hard shadow wrapping around the highlight using solid Black. I give it a narrow gradation to blend it with the yellow. Next, on the right, I add some shading with a brown color, here it is Light Umber.

To add richness, I apply some Orange on the left to make the colors more complex and full. But the real magic trick here is the final shading on the right. The physics of a glass ball have some interesting peculiarities. Here, there is an internal reflection of the shadow, which looks like this. Using Black, I lightly add in the reflection, making very sure that it floats in the shadow area, but NOT TOUCHING the far edge.