Envelope Guide
Which paper fits which envelope?
C6
A5 fold once A4 fold twice
DL
A5 fold once A4 fold twice
C5
A5 unfolded A4 fold once
C4
A4 unfolded
What do the measurements mean?
Size of opening
The second number of the size measurement is the size of the opening
of the envelope
What Sealing Types Are Available?
Peel and Seal 
Simply peel away the release tape from the envelope flap underneath is a layer of adhesive which seals instantly with a strong bond on contact, seal strength does not weaken with age. Traditionaly a more premium option and associated with thicker, higher gsm envelopes.
Press Seal 
Simply press the two layers of adhesive (one on the envelope flap, and
the other on the envelope body) together to form an instant strong bond,
seal strength weakens after a 6 month period. Usualy the best value, and most efficient for large mail outs.
Gummed Seal 
Moisten the layer of adhesive along the envelope flap to close and the
most economical seal type option for envelopes.
Twin Gummed
Double the amount of adhesive for a strong seal
What Are Window Posistions?
Windows on envelopes are measured in from the left of the window and up from the
bottom of the envelope, and looking at the envelope with the flap at the top. 
What AreEnvelope Paper Weights?
Paper weight is usualy in grams per square metre (gsm) in the Uk, usually the heavier the weight the stronger the envelope.
| Weight of Envelope (Gsm) | Purpose, Uses, Description |
|---|---|
| 80gsm | Standard weight for everday mailing |
| 90gsm | Standards weight for mailing heavier documents |
| 100gsm | Medium weight suitable for letterhead correspondence and prestigious mailings |
| 110 - 120gsm | Heavy weight premium suitable for letterhead correspondence and prestigious mailings |
| 125gsm | Heavy weight premium suitable for heavy important mailing, prestigious mailings of bulky items |
How Can I Send Bulky Goods, and Documents?
Paper Envelopes - Gussetted
These are made from an heavy duty paper usualy with a higher gsm, and provide a gusset for expansion usualy around 25mm.Also available with reinforced woven polyester thread.
Paper Envelopes - Board Backed
These are made from an heavy duty paper usualy with a higher gsm, the rigid board keeps important documents safe and sometimes supports a printed message on the front "do not bend"
Polythene Envelopes
These are bags which some manufacturers claim are lighter and stronger than conventional paper envelopes and so save money on postage costs.
Bubble and Padded Bags
These are made from an heavy duty paper usualy with a higher gsm, and contain a padded bag fixed into the inside of the envelope to protect the contents.
Postal Tubes
These are usualy made from a strong cardboard material, with a top that pops out so documents can be rolled to fit inside to protect while being delivered.
FAQ's
Using Envelopes in Printer
Most envelopes are compatible with inkjet and bubble jet printers, however it is best to check your printers manufacturer, or user manual to check compatability. Press seal however are usualy incompatible with laser printers due to the heat process in laser printing.
Can Envelopes Match Business Paper?
Envelopes come in various finishes and if you know the gsm of your paper the process of matching an envelope can be quickly matched.
What is Opaque?
Standard envelopes can be see through in the right light and as rare as this may be there is a chance some of your correspondence may be read if not folded or posistioned correctly in the envelope. By coating the inside of the envelope with a colour wash the contents are un readable.
What Are The Envelopes Used For Deliver Documents?
These are usually refered to as "documents enclosed" envelopes (as this is what is printed on the front), but some do come plain they are called tenzalopes.