Deciding on a type of envelope can be very confusing due to the number of options available. While paper has four main criteria – namely size, weight, colour and finish, envelopes have all of these plus specific type, window position and sealing method. It is possible to print onto pre made envelopes but we can also print on a flat sheet of paper before converting into an envelope, each option having its advantages.
As with paper there is an internationally recognised standard for envelope sizes and for with envelopes paper’s ‘A’ prefix is replaced by the ‘C’ prefix. The exception to this is the DL envelope which is the commonly used size for letters and along with C5, falls within Royal Mail’s ‘Letter’ pricing bracket.
As well as the standard envelope sizes listed below we can produce bespoke envelopes which often make up an important part of a marketing pack or direct mail campaign.
Standard Envelope Sizes
- C6 – 114mm x 162mm – A5 folded once or A4 folded twice
- DL – 110mm x 210mm – A4 folded twice to 1/3 A4
- C5 – 229mm x 162mm – A5 or A4 folded once
- C4 – 324mm x 229mm – A4
- C3 – 457mm x 324mm – A3
Other Popular Sizes
- 155mm x 155mm
- 190mm x 190mm
- 220mm x 220mm
Envelope Styles and Types
- Banker – the traditional diamond flap envelope ideal for invitations and greetings cards
- Wallet – opening on the long edge ideal for corporate letterheads
- Pocket – opening on the short edge, most common on envelopes larger than DL
- Window – a clear acetate that covers an aperture to reveal details, usually a name and address
- Board Back – a stiff board is used to protect the contents from being bent or creased when in transit
- Gusset – folded sides that can expand to accommodate bulkier items
- Air Padded Bags – the body of the envelope is made from paper and plastic comprising of bubbles that act as air pockets to provide protection and security.
- Poly Bags – a clear polythene bag that is transparent to reveal the contents.
The three most common types of envelope sealing are:
- Gummed – a small layer of dry adhesive that when moistened re-activates the glue for sticking. These where the first type of envelope to carry their own sealing mechanism and whilst not the most pleasant to use if licking yourself they are used for direct mail when using automatic enclosing machines. It is possible to steam open but generally speaking they are a relatively secure method of sealing an envelope. They can be stored for a fair amount of time before the glue discolours or becomes unusable.
- Self Seal – the most common envelope used today. Two layers of adhesive are used, one on each edge of the opening that when pressed together form an instant tight seal. They are quick and easy to use and although they can be re-opened which could potentially be a security issue they economical and widely used. The seal strength can begin to weaken in a relatively short space of time so it is not recommended to store this type of envelope for more than 6 months.
- Peal & Seal or Strip Seal – perhaps the easiest and quickest sealing method. A thin peel away strip of paper on the edge of the flap reveals a layer of adhesive that when press down forms an instant strong seal. These envelopes can be expensive but will store for a very long time without deteriation and once opened cannot be resealed making them very secure.
When quoting an envelope’s dimensions you always give the edge with the flap as the second dimension. The classic DL envelope therefore has a dimension of 110mm x 210mm when the flap is on the long edge. When using envelopes that have a window, the window size is quoted depth first and width second. The window position is quoted as the distance from the left hand edge of the envelope and then the distance from the base of the envelope.