Click the image below to view it in full resolution. 
This tutorial will utilize my personal illustration as a guide. Feel free to use your own illustration or refer to the source file available at the conclusion of this guide for step-by-step instructions.
Ensure your scanning is done in black and white to maintain solid black lines without any soft edges. This is crucial since we’ll be isolating the line art onto its own layer, making the process much smoother with clean, solid lines.
After scanning the image, open it in Adobe Photoshop. Our goal is to separate the inks onto individual layers for enhanced control. To achieve this, select the white background and delete it.Press Ctrl/Cmd + Alt/Option + 2 (for Photoshop CS4 and later) or Ctrl/Cmd + Alt/Option + ~ (for Photoshop CS3 and earlier). This command surrounds all light-colored areas of the layer. Tip: Familiarize yourself with Photoshop shortcut keys; they can significantly save time.
Press Delete to remove the selected white areas, leaving only the line art on this layer. 
Create a new layer (Shift + Ctrl/Cmd + N) and use Edit > Fill (Shift + F5) to fill the entire layer with white. Move this layer beneath the line art layer and lock it; no further changes will be needed.
It’s advisable to erase as many pencil lines as possible before scanning inks to reduce workload in the digital stage. However, digital cleanup of inks may still be necessary.Let’s perform some cleanup! With the inks on their own layer, use the Eraser Tool (E) to remove any unwanted marks. 
Flattening (or flats) involves blocking in color to act as placeholders.Flats are not your final colors; they aid in efficient coloring and rendering. The term originates from the comic industry’s coloring specialist, the Flatter. Begin by creating a new layer beneath the line art layer.Next, select the Lasso Tool (L) and ensure the Anti-alias option in the Options Bar is unchecked. 
Trace the line-work with the Lasso Tool and fill (Shift + F5) the Lasso selections with your desired color. 
The completed flat for the face should resemble the following: 
Continue this process until all areas are covered. In essence, any area intended for coloring will have a distinct color flat. It doesn’t matter which colors you choose at this stage, as long as the same colors don’t touch. Your final flats should appear something like this: 
This process can be time-consuming, but the time spent flattening could easily save three hours in the final coloring stages.Once the flats are complete, lock the layer. This is where you start making choices and experimenting, as it’s time to color! Ensure your flats layer is locked.Now, select the Magic Wand Tool (W), set the Tolerance option to 0, unchecked the Anti-alias and Contiguous options (all adjustments can be made in the Options bar). 
Use the Magic Wand Tool to select different colors on your flats layer and fill (Shift + F5) your colors on a new layer above it. 
I’m aiming for a purpleish overall tone with a yellow/green background, but I may opt for a red, green, or even a yellow tone later.Since I can return to my flats layer and grab anything I want, everything can be altered or fixed. This is one of the major advantages of flattening. For now, I’ll stick with the colors shown below.
This is another stage where your choices are limitless. You could simply leave these colors flat or create a custom brush to start painting. For this piece, I’ll go with a basic cel-shading style — a blue shadow on everything.I’m doing this because I know I’ll be experimenting with various watercolor textures later, and I don’t want an overly rendered look. With the Magic Wand Tool (W), select all areas of the Hunter and his Horse. Choose a nice blue shade color and start coloring where you want your shadows.I did this on a single layer to minimize the number of layers and conserve machine power to prevent crashes or lag. Here’s the result: 
Next, create a new layer above the shadows layer to add gradients to the background and the shield. Use the Magic Wand Tool (W) to select the background.Once selected, use the Gradient Tool (G), set to Linear Gradient and the Foreground to Transparent preset in the Options bar. 
I scanned in various watercolor textures that I made. (If you’re following along with the provided source file at the bottom of this tutorial, they are included in the layers.) 
If you’re scanning in your own textures in Photoshop, switch to the Move Tool (V), Shift-click on the scanned-in texture, and then drag it into our main document.(An alternative option is to use the Watercolor Textures: Photoshop Brush Pack.) It will look something like this: 
We want this texture to affect only the Hunter. In other words, we want to remove the texture from the Horse and the background. This is where flattening becomes quite helpful.Return to the flats layer, use the Magic Wand Tool (W) to select the background and the horse, and then press Delete. Now our texture is only affecting the Hunter and a bit of his saddle. 
To add more depth, adjust the layer’s Blend Mode and Opacity.There are many cool effects in the different layer modes, but for this tutorial, we’ll use the Overlay mode. This is one of my favorites when working with textures. Select the texture layer, set it to Overlay.Next, lower the texture layer’s Opacity to reduce the intensity — decrease the dial to about 63%. Feel free to experiment. 
This is the most basic way to deal with textures.Using this method, I dragged over a few more textures into the piece and isolated them to certain areas using our flats. I ended up with this: 
Using the method above, complete your textures.The illustration is nearly finished but requires a little refinement.This is when I usually start experimenting with adjustment layers. These are excellent because they allow for various effects without altering the pixels of your image. I want to add a little color to the line art.The stark black of the line art contrasts with the muted palette. Let’s tone it down. Click on the inks layer to make it the active layer, then click on the Create new fill or adjustment layer icon (it looks like a black and white pie) at the bottom of your Layers panel, and choose Solid Color.
Since it has a lot of purple, I want the inks to blend in instead of standing out. I’ll select a purple color. The entire layer should be filled with the color you’ve chosen.In this case, purple. 
Essentially, the adjustment layer affects everything beneath it, but we only want to affect the layer directly beneath it (the inks layer). So right-click on the Solid Color adjustment layer and choose Create Clipping Mask from the menu.
The result should look like the following: 
However, the outcome seems too bright still. Lower the Opacity of the adjustment layer to about 33%. 
This all looks good to me at this point, and I’m going to call it done!To finalize, flatten the image. Right-click on any layer and choose Flatten Image from the menu that appears. You can also do this from the
