Step 1: Scan your image
Draw your image as a line drawing with black medium (I used a pen). It is important to get as much contrast between the paper and your medium as we will be subtracting the white from the image at a later stage. Scan your image as a TIF or JPEG at a minimum of 300dpi. The more quality to your image, the more refined your final product will be. Click image to view full size
Step 2: Adjust your levels
If necessary, once your document is scanned in – open it in Photoshop and adjust the levels (Ctrl/Cmd + L) to increase the contrast of the black and white. Move the black and white arrows closer to the grey (middle) arrow respectively. Make sure you don’t adjust the levels too much as it may hinder the quality of the image rather than enhancing it. Save your image once you are happy. Click image to view full size
Step 3: Import your image into Illustrator
Place your saved image into Illustrator by going to File > Place and locating the file on your drive. Once placed, check your ‘Control’ panel is showing by going to Window > Control and ensuring you have a tick located next to it. If successful, once you click your image – you should see a panel with ‘Embed’,’Edit Original’ and ‘Live Trace’ buttons on it (as seen at the top of my screenshot located below). Click image to view full size
Step 4: Live trace your image
With your image selected, live trace it by clicking the ‘live trace‘ button on your control panel. After it has rendered, you will see a vectored interpretation of your artwork, which hopefully won’t too much different to your image. If for what ever reason it doesn’t look quite right, select your image and adjust the ‘Threshold’ slide bar in your control panel. This will determine how much black and white the trace renders. Once you are happy, ensure your image is selected and click the button in your control panel. Select all of the vectored points with your cursor (Make sure the Black Cursor selection tool is highlighted in your toolbar and drag an imaginary square over your artwork to highlight everything). Once everything is selected, ungroup your image by going to Object > Ungroup (or Shift + Ctrl/Cmd + G).
Step 5: Remove the white elements of your image
In your toolbar, click the Direct Selection Tool (white cursor) and click a white area of your broken up image. Once selected, go to Select > Same > Fill Color. This should now highlight all the white areas of your image. As we want make the image transparent, delete these selected white areas. Select your remaining black lines again by dragging the selection tool over the artwork, regroup them (Ctrl/Cmd + G) and lock the artwork (Object > Lock > Selection or Ctrl/Cmd + 2).
Step 6: Select your brush
With your artwork locked, access the brushes panel by going to Window > Brushes. Once up, click the icon in the bottom left of the panel to access the Adobe brush library. Here there are a nice selection of brushes that will do a decent job of replicating mediums such as watercolour and pastel. I have always found the watercolour brushes to be effective, so this is what I will use for mine. Feel free to choose differently if it doesn’t work with your imagery.
Step 7: Get painting
Paint over your locked lines with your chosen brush (ensuring the paintbrush is selected in your toolbar). If needed, adjust the stroke thickness of the brush (if the stroke thickness option is not apparent on screen, go to Window > Stroke) to make your brush strokes thicker and thinner. Feel free to adjust the opacity of the individual stokes too (Window > Transparency) if you want to give the strokes some show-through. TIP: If you drew your artwork from an image, you can import the image to your file and source the colours from it using the pipette tool to give the colours a more realistic approach. (Mine however uses the surreal colour approach!)
Step 8: Send your brushes to back and admire your finished piece!
Select all of your brush strokes (drag over them using the selection tool) and send them to back (Object > Arrange > Send to back or Shift+Ctrl/Cmd + [). All done!