To complete the shading add a new layer (called ‘Highlights’) and, using the Magic Wand, select areas like the eyes and teeth – we’ll add more shading to further define the areas. Once these areas are selected, grab a small white paintbrush, set to 50% opacity, and paint around the areas you want to highlight, to add some gentle shading. This will help these areas really pop.
Merge the various gradient shading layers; this should leave you with gradients on one layer, and the highlights on another. Create a new greyscale document to the same dimensions as your working document, and drag the gradient layer into it. Select Image > Mode > Bitmap and click OK if it asks to flatten layers. Make sure the output is set to 300dpi and that the method is set to Halftone Screen.
In the next palette, set the angle to 45º and the frequency to 40. Convert the document back to greyscale and drag the layer into your main skull image. Repeat this for the Highlights layer.
Now set both shading layers to Screen and make sure the old shading layers (non-bitmapped) are invisible. Position them correctly and merge the new shading layers with the linework layer. Now we need to set up the final document, in which we’ll repeat the skull and then fill and complete the pattern using other elements.
Select File > New and create a 35-x-25cm document for print. Drag the skull into the new document and position it centrally. Use View > New Guide then set guides to 50% vertically and Horizontally. Now use the Free Transform guides to align the skull centrally.