Adding texture to your illustration can make it look more like it was hand drawn. And it’s not really that hard to do either. First thing you need to do is take a colored pencil (the same color you want to add texture to) and color a patch on a piece of paper. The best way to do this is to color it diagonally in both ways so it looks like the colored lines are crossing. Then you need to scan the image (at least 300dpi if it’s intended for print).
Adding texture in Adobe Photoshop
Open your scanned image in Adobe Photoshop and press ctrl-A (cmd-A on mac) to select the entire image. Navigate to edit/define pattern. A new box opens up and all you have to do is name your pattern.
Now open the file containing your illustration. For this to work the best all colors must be put in separate layers. That means all red colors are in one layer, all blue colors are in one layer, etc. For this example we’ll be adding texture to all red colors. Select the layer that contains red colors and double click it or right click it and select “blending options”. Navigate to pattern overlay and in the pattern box select the red color pencil pattern from the roster. Set the opacity to your liking (I usually set it to about 20-30%) and that’s basically it. Do the same for all other colors.
Adding texture in Adobe Illustrator
Open your illustration in Adobe Illustrator. Navigate to file/place and select the scanned texture. This places it on your board. Now select the direct selection tool and drag the placed image in to the swatches palette. Now you can delete the placed image on your board.
Now with the direct selection tool select a surface you want to add texture to. You can alternatively use the magic wand tool to select all the surfaces of the same color so you don’t have to edit every surface individually. Navigate to window/appearance. Duplicate the fill layer (select the fill layer and click on the new layer button on the bottom). Now in the top layer select the swatch that contains your texture. Set the opacity to your liking (again I set it to about 20-30%) and that’s it. Do the same for all other surfaces and you’re done.
Here’s a comparison: