A Pattison Superboard is 18 x 14' giving it at aspect ratio of 3.43:1.
Quoting to shoot a series of photos to refresh a client's portfolio of billboards is a more complex task than I had originally imagined. Pattison's "S14 Superboards" pose a unique problem for a photographer looking to use a single frame to fully cover the entire area of the billboard as the aspect ratio of these boards is 3.43:1. Cropping a 4:3 sensor area like that from most medium format digital backs means you're left with only 39% of your camera's pixels (4/3 x 1/3.43 = 0.388727). Cropping a 3:2 aspect ratio sensor leaves you with 44% of your pixels. Cropping a 1:1 aspect ratio sensor leaves you only 29% of your pixels. One may argue that there is the possibility of using a sliding digital back adapter or some other panoramic shift system to elongate the aspect ratio of a frame by doubling its width so you'd end up with 8:3 (80%), 3:1 (88%), and 2:1 (58%) aspect ratios (remaining percentage after crop). However, that makes it unfeasible to have non totally-stationary elements (like people) cross the centre of your frame. There is also the prospect of shooting film. If one were to shoot 6x17 (56 x 168mm actual size), making the contreversial assumption that a typical ISO negative film (with hopes of improving on the exposure latitude of a higher resolution slide film) shot 24 x 36mm has the equivalent power to resolve about 8megapixels worth of information, you're looking at approximately 100 pixels per linear mm. 6x17 has an aspect ratio of 2.83333 meaning that to crop to Superboard aspect ratio we'd be down to about 83% of total resolution (56x100 x 168x100 = 94,000,000). One may also suggest shooting bigger film (17cm is just under 7" giving the cropped resolution of a 6x17cm shot very similar to that of a cropped 5x7" shot) but until you hit 8 x 10 you are not realizing much benefit, if at all and with 37% efficiency after cropping you realize that you just aren't gaining that much, you have to use significantly larger and heavier equipment, and you are paying much more for processing.