In my quest to "find my style," I've spent a lot of time trying to figure out what I do and don't like in my drawings. One thing I've discovered I surprisingly like a lot is the sketchy graphite linework in my initial thumbnail sketches, so I'm trying to find ways to bring that into my finished work.
I've been taking some Skillshare classes recently to work on the Photoshop skills necessary to make nice pencil lines in digital art and wanted to share a tutorial for my new favorite method.
1. Scan your image in grayscale at 300dpi or higher. Open the image in Photoshop and use the Levels tool to make the pencil lines dark and the paper white.
2. Use the Hue/Saturation tool to completely desaturate the layer with your pencil drawing by dragging the slider for the "Saturation" setting all the way to the left.
3. Open the channels window. Command+click (Mac) or Control+click (Windows) the thumbnail of the RGB channel to select the lineart. You'll see marching ants appear around your image. Select the inverse by going to Select > Inverse or using Shift+Command+I (Mac) or Shift+Control+I (Windows).
4. Make a new layer above your original image layer. Turn off visibility of the scan layer by clicking the eyeball next to the layer thumbnail.
5. Using the Paint Bucket tool, fill the lineart with your desired color. I found that clicking in the selection multiple times with the Paint Bucket gave me a darker color that I liked. You can experiment to see what suits you. You can also use the Eraser tool to clean up any extra bits. For instance, I had a cat hair in my scan to erase. Wonder how that got there...
Once you're happy with the darkness and color of the lineart, deselect your selection by using Command+D (Mac) or Control+D (Windows).
6. Lock the transparency of the lineart layer by clicking the appropriate button in the Layers window.
7. You now have a layer with just your lineart and no fill in the background. With the transparency locked, you can use the Paint Bucket or Brush tools to color your lineart. Create a new layer below the lineart to color in your drawing using your preferred brushes or other coloring techniques.
And that's all there is to it. With this method, you can create icons without any background to layer in images in any way you choose. This is a great method for those trying to license designs because it gives the client a lot of options on how to use the icons.