Unlike other popular sans serif fonts such as Arial and Verdana, the Gill Sans typeface uses a double storey lowercase g. This has a distinctive eyeglass shape, which is easily recognisable.
Gill Sans is also essentially the only sans serif typeface without modular use of strokes. The “O” is a perfect circle, and the oblique and vertical strokes as well as upstrokes and downstrokes have a consistent thickness. Only “a”, “e” and “g” have thinner strokes at the openings of the small eyes. These exceptions to an otherwise consistent stroke thickness are one of the trademark characteristics of the Gill Sans typeface.
The letter a was originally developed with straight tail, followed by diagonal tail – which can be seen on early specimen sheets –, then the hooked tail. The diagonal tail eventually came in Extra Bold and Bold Extra Condensed, a modified straight tail was later found in Ultra Bold.
Following the humanist model the lowercase italic a becomes single story
The original Gill Sans lacked distinctions between numeral “1”, uppercase “I”, and lowercase “l”, so alternate version of Gill Sans was made that included an alternate “1” that could be used for numerical setting, such as shop window prices and timetables. In the Adobe version, such alternate figure is not included, even in the OpenType version of the font.
The font is a superfamily and comes in 24 different weights. It can be discussed if the extreem weights in many cases are actually harming the font, and Gill was also labeling his diagrams with terms such as “sans overbold”, “hardly recognisable” and “fatuous”, to drive home his point about the distortion of letterforms in the heaviest weights. Yet this is exactly what happened to Gill Sans – rather than refuse commissions for Extra Bold and Ultra Bold – well beyond the weight of what was considered normal –, he continued to draw up and deliver designs that he knew to be aesthetically unjustifiable.
Eric Gill got it wrong; a re-evaluation of Gill Sans