Youre probably thinking this is some new ecological way of using Adobe Illustrator. Sorry! The only way to do that is to use energy-saving bulbs to light your work area. What well show you, however, is how to use the Mesh tool to simulate natures way of colorizing thingsin this case, a fallen leaf.
Heres a fairly flat-looking maple leaf made from two layers: The bottom layer contains the leaf and the layer at top contains the veins.
Create the mesh
What the leaf needs is some color to make it look more dimensional and natural and this is where the Gradient Mesh comes in.
First, well create a new blank layer between the two existing layers. In this new layer, well generate a box that has the same fill color as the leaf and covers the complete shape of the leaf. This layer is where well create the gradient mesh and add the colors.
Click on the Toggles Lock box (to the left of the layer name) of the other two layers that contain the basic elements of the leaf. This is important because well be doing a lot of clicking to create the mesh, and locking the layers will prevent them from accidentally being selected and altered.
Now if you study the veins on the leaf, youll notice that they break up the box into two columns, each with four rows. Armed with that information, choose Create Gradient Mesh from the Object menu. In the dialog that pops up, enter the parameters established by our observation of the leaf, and click OK.
Using the Direct Selection tool (A), move the center anchor points of the mesh to intersect the joints where the six horizontal veins branch off from the main central vein. Also, move the anchor points on the outer edges and adjust their handles so the mesh matches the shape of the veins.
Add new grid lines above and below the horizontal veins and to the left and right of the central vein. To add new grid lines, click with the Mesh tool (U) anywhere within the grid. This will create both a vertical and horizontal grid line that intersect at the point where you click. These new grid lines will automatically follow the flow and direction of the existing grid lines that border on either side of them. (Note: Once you create one of the new vertical grid lines for the central vein, click directly on that line when adding horizontal grid lines. Otherwise, youll add additional vertical lines that you dont need.) We need to alter these new grid lines also: Using the Direct Selection tool, move them and adjust their handles to start forming a shape within the leaf where the colors will flow.
The beauty of the Gradient Mesh is that colors can be added that will fade into any other colors that exist within the mesh. To add colors to the mesh, simply select anchor points in the mesh and then choose a color. The color will automatically fill the area around the anchor point and fade into whatever color is assigned to the next anchor point in the mesh. Note: Any alteration to the shape of the mesh will alter the shape of the color and how it fades into neighboring colors. Lets try it with our leaf:
In the middle layer with our leaf color, use the Direct Selection tool to select all the points that travel through the original grid lines that are directly on top of the veins (add the Shift key for multiple selections). Once all the points are selected, choose a dark brown color to fill those points. Notice that the color falls behind the veins because the veins are in a layer above the layer where the mesh is contained.
Click on the vertical lines to either side of the central vein to add two new horizontal grid lines that fall in the center between the horizontal veins. Add two new vertical grid lines to the left and right of the existing vertical grid lines. These new vertical lines will serve as the stopping point for the colors that are about to be added to the newly created horizontal lines. Select the four points on the two new horizontal lines where they intersect the vertical grid lines on either side of the center vein in the leaf. For our example, we added a pink tone to those points.
Select the points at each juncture where the veins branch out and add a green color to these points. Finally, adjust the various outside points that border the dark brown tones, which allows you to spread the browns and vary their effect over the leaf.
Now that the color is complete, place the middle layer with the colored box behind the layer with the leaf. Unlock the leaf layer, and then clip the two layers to form a mask (Object>Clipping Mask>Make). And heres our more natural-looking leaf.
The Gradient Mesh Tool is a wonderful way of playing with color! Couple it with a little solar power and its a very environmentally friendly tool.
Quick Tips on the Mesh Tool by Corey Barker
As Bert mentioned in Step Four, you can add additional horizontal and vertical grid lines to the gradient mesh by clicking in an empty area with the Mesh tool. You can also click directly on a vertical grid line to create a new horizontal grid line and vice versa. Now if you add an anchor point that you didnt mean to, hold down the Option (PC: Alt) key and hover over a grid line. When the cursor changes to a minus sign (), simply click on the undesired grid line to remove it.
Now lets say youve edited all the individual points with varying colors and when you look at the finished graphic, you decide youd like to see other color variations. Well, you could go and select each individual point and change the color if you had all the time in the world. However, seeing as how most of us dont have that luxury, we can simply select the object with the Selection tool and click on the Recolor Artwork icon in the Control panel. In the Live Color dialog, make sure the Recolor Art box is checked on at the bottom. Then click the pop-up menu at the top left to access the various Harmony Rules and experiment with different combinations.