Walkthrough that no one asked for but made anyway because I had extra copies of the file lying around
1. Sketch, duh (not shown, me sketching over the thumbnail that usually looks slightly better than chicken scratch)
2. Cleaned up the lines with the binary tool on SAI. For the wall and window, I made a vector layer to draw lots of straight lines, then manually drew in the little touches.
3. Add the values using the marker tool that’s set to ‘multiply’. This way you can get darker gray without fiddling with the color wheel too much. I only used two shades of dark gray in this pic. Make sure the gray layer is set on multiply.
4. Underneath the gray layer add the flat colors, keeping in mind that the flats look even more hideous if you turn off the gray layer. Adjust colors as needed.
5. I wanted this to take place in the night, so I added a blue layer clip set at a lowish opacity on either multiply or overlay mode on top of the gray layer. This is only temporary, since the layer clip looks like crap on top of gray—it just gave me an idea of what I need to adjust. (Not shown: duplicating the gray layer so there would be more contrast).
6. I switched over to Photoshop, made a white layer to merge with the gray layer, used the tint function under “Image—>Adjustments—>Black and White,” and reset that layer to multiply again. Afterwards it was a matter of making adjustments to the color and adding a texture layer to give it a more ‘traditional’ feel.
(The original image had more of the wall and the trees—I had cropped them so there would be more focus on Kashima and Hori :’3)