These are basic envelopes for frequent use sold at a good price even when only buying small amounts. The white ones have been printed with grey colour on the inside of the mailer with an eye to keeping the contents away from prying eyes. The brown version, of course, does not need this addition because you cannot see through them anyway.
The larger the mailer, the higher grammature of the paper used. In deciding on which grammatures would be best for the larger mailer we turned to the heavier values because, on the one hand, firmer paper provides greater stability while on the other because in the case of larger letters there is more margin vis-à-vis the postage requirement, meaning you do not have to worry about every gram like you do with standard letters.
Here are the respective grammatures:
- C5 format: brown natron paper ca. 90 g/m² or, alternatively, white offset paper ca. 90 g/m²
- C4 format: brown natron paper ca. 110 g/m² or alternatively, white offset paper ca. 90 g/m²
- B4 format: brown natron paper ca. 110 g/m² alternatively, white offset paper ca. 120 g/m²
Envelopes are usually available with three different types of seals. In order to avoid any confusion, here is a short explanation of the most used terms:
- A gummed envelope has a strip of gum on the flap that is activated by moisture (licking).
- A press seal envelope is closed by folding down a flap and pressing the two strips of glue together. No moisture is required.
- Peel and seal envelopes are closed by removing the strip that covers the adhesive on the flap and pressing the flap into place.
What is the difference between envelopes on the one hand and mailers on the other? An envelope on which the flap is on the short side is called a mailer; if the straight or pointed flap is on the long side it is called an envelope.
The most common sizes of mailers are as follows:
DIN C5 162 x 229 mm
DIN B5 176 x 250 mm
DIN C4 229 x 324 mm
DIN B4 250 x 353 mm
DIN E4 280 x 400 mm
Size and position of the DIN window:
DIN C5, B5:
The size of the window is 45 x 90 mm and its position when the mailer is horizontal is on the left (flap on the right) with a 60 mm margin from the bottom and 20 mm margin from the left side.
The size of the window in 55 x 90 mm and its position when the mailer is upright (flap at the top) is on the left side with a 212 mm margin from the bottom and a 20 mm margin from the left.
Because the post office is constantly changing the maximum size and limitation parameters, we refer you here to the hopefully always current Deutsche Post webpage: www.deutschepost.de. There you can also consult the German post office postage calculator (only in German although some info in English can be found on the Internet).
Similar webpages for other countries can be easily found in the Internet