In signage a pictogram is the image used to convey the message of the sign. In statutory signage pictograms follow a very specific set of colour, shape and sizing rules. In UK and EU signs the width of a sign's pictogram is set at 80% the height of the area it is printed to.

For example :
On an A4 Portrait sign (210 x 297mm) using 2 thirds of its area to display the pictogram 210 w x 198 H (mm) and 1 third for its text display, the pictogram would be 158.4 mm wide. (80% of 198mm).

For a pictogram to work it must be instantly recognizable and understood by all. For this to work the image must be kept consistent. In its purest form a pictogram on a sign should be understood even if there is no text present. Following the standard colour and shape rules increase the likely hood of a universally understood pictogram and therefore sign.

Signs have very specific shapes. These shapes on signs send messages to the audience and form a set of rules that should be followed when developing signage.

Squares signs are used to portray information to an audience. This is found in safe condition signs, public information signs and fire equipment signs. These signs provide information to a audience. Where something is, what something is and similar information.

In contrast a circular sign is an instruction that must be followed. Both the mandatory and the prohibition signs provide instructions that cannot be ignored.

Finally We come to the triangle of the warning sign. This is used to convey DANGER It can also provide information but is primary purpose it to quickly tell you to be aware and careful.

Warning signs are used to indicate the presence of hazards or hazardous materials. It recognizable as a yellow triangle with a solid black border and a black pictogram on it. signs from this category of sign include Danger signs, radiation signs, risk of drowning signs and hazardous material area signs.

The prohibition sign indicates actions that you MUST NOT do. It is recognized by the bold red circle with a diagonal bar running from the top left to the bottom right. The pictogram is displayed in black with this circle overlaying it. Examples of this sign type are No Smoking signs, Do not touch signs and No exit signs.

Mandatory signs indicate that a specific course of action MUST be taken. These signs have white pictograms on a blue circle. Examples of this type of sign are now wash your hands signs, keep locked signs and keep this area litter free signs.

Fire equipment signs are used to indicate the location of fire fighting equipment. This class of sign have white pictograms on a red square. Signs of this class include fire alarm, fire extinguisher and fire ladder signs.

Public information signs have black pictograms on a white square with a black border and are used to convey general information to the public in an easy to understand form. Male and female toilet signs, checking and booking desk signs are just a couple of examples of this type of sign.

This class of sign, features a white pictogram on a green square. They are used to indicate the location of emergency facilities and areas. Signs from this category include first aid signs, emergency exit signs and life jacket signs.