No symbol
From Wikipedia, the free encyclopedia
The no symbol (or universal no) is a circle with a diagonal line through it (running from top left to bottom right), surrounding a pictogram used to indicate something is not permitted. The No symbol is usually colored red.
The Unicode for the no symbol (also called the "Prohibition" symbol) is U+20E0; ( ⃠ ). It is a combining character, which means that it appears on top of the character before it, so putting A⃠ will show A⃠. (Note: this will only appear if you have the font needed.) It also appears in the Webdings and Wingdings 2 fonts.
Under a UK Statutory Instrument, the red area must take up at least 35% of the total area of the sign within the outer circumference of the "no symbol". So 35% of everything within the outer edge of the "no symbol" must be the symbol itself. Additionally for printed signs, the width of a "no symbol" is set at 80% the height of the area it is printed to.
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[edit] Uses
The "no" symbol is used on traffic signs, so that drivers can interpret traffic laws quickly while driving. For example:
No left turn
No U-turn
No parking
By analogy, the symbol is used in public places to refer to prohibited actions not having to do with traffic:
- No smoking (with icon of a lit cigarette)
- No littering (with icon of person littering)
- No swimming (with icon of swimmer in water)
It is also used on packages sent through the mail, and sealed boxes of merchandise that is sold in stores. Using a graphical symbol is useful when the item must be handled by people who understand different languages as it is transported. For example:
- Breakable; do not drop
- Keep away from magnetic fields
In product documentation, this may be accompanied by drawings of the product being threatened by the prohibited items: for instance, a cartoon of a floppy disk being menaced by horseshoe magnets.
It is also used on clothing, linens, and other household products to indicate the care, treatment or cleaning of the item. For example:
- Do not iron
Also, many companies use the "no symbol" when describing the services they offer, e.g. an insect deterrent spray brand symbol showing the "no symbol" over a mosquito. The Ghostbusters logo is a fictional example of this.
[edit] International Standards
Whereas the "no symbol" has been so widely used in advertising and promotions that now any variation of the "no symbol" design flipped left or right or varied in hue is considered acceptable and recognized by the general public as a symbol of prohibition, it is still governed by local and international standards. The definitive definition of the no symbol comes from the International Organization for Standardization.
In 2002, ISO 3864-1 was published (a revision of a standard first published in 1984). The introduction includes language on the need for using as few words as possible to convey information.
ISO 3864-1 sets the rules for the color and shape of safety signage, as well regulating the incorporation of text according to viewing distance and sign size. The range of color and shape defined in this standard for the "prohibition symbol" or "no symbol" is defined as "a prohibition surround shape (red circular band with a red slash going from the upper left to the lower right) over the top of a black graphical symbol."
[edit] Variants
In contrast, a green circle with no line through it may be used as a Yes symbol, indicating that the activity represented inside the circle is permitted, but this is not official. It is mainly used to give advice, rather than to say what must be done.
Sometimes it's called an 'anti symbol'.
In the UK, a filled blue circle (with no white inner circle) is used for positive signs, e.g. the wearing of a helmet on a building site, or the fact that a pathway is for pedestrians and cyclists. The 'no' symbol does not always have the 'slash' across it; in all traffic uses other than no turn, European 'no' signs are illustrated just with the prohibited action circled in red. An exception to this is the "No stopping" or "clearway" variant, this is illustrated with a red circle with a blue background and two diagonal 'slashes' forming an X. However according to the UK highway code signs with red circles are mostly prohibitive, and classifies these signs as "signs giving orders" rather than prohibition signs.
