With the friendly help of Steve from www.bulliesofnc.com (thank you, Steve) I was able to turn my original chart, which I had first set up months ago, into a neat reference on Bull Terrier colors.
Feel free to share this image. A printable version is available on request, if you want one.
In a word – Unusual
Bull Terrier Appearance: The Bull Terrier’s appearance needs some getting used to
The Bull Terrier appearance needs some getting used to. These funny little power packs have a strong, firm and above-average muscular figure as well as a keen and determined expression. The long oval head is gently shaped downwards with a characteristic egg shaped contour (= down face). The eyes are small, dark and triangular in shape. The ears are small, standing closely together, pointing upwards. The nose is usually black, but can show some pigmentation, and is slightly bent downwards.
The chest should be brad from the front, the body contour well rounded with a short, strong back. The back is slightly arched over the loins. The rib cage should be a little bit visible.