Creativity is an important factor for a successful mailing. However, trouble-free mechanical processing is also important as manual sorting can thus be avoided. This way you benefit from lower costs and we are able to guarantee the service.
Please observe the following recommendations on the layout of mailing envelopes.
Glossy surfaces make it more difficult to find the address block and read the address by machine. Gloss-coated papers with gloss values higher than 59% (Tappi) should be avoided as far as possible.
Tip: wherever possible use paper with a matt or matt-coated surface.
Address characters must stand out clearly and distinctly from the background so that they can be read easily by machine or by the human eye. Black characters on a homogenous white background are ideal. However, slightly grey tones (e.g. recycled paper) or slightly pastel-coloured envelopes are also acceptable.
If you do not choose the ideal white address or barcode zone, you can use the following backgrounds on the basis of the four-colour printing euro colour scale:
The address and coding zone must not include any patterns, such as logos. The address print must be dark: 80-100% black according to the euro colour scale. Make sure that the address is printed evenly, boldly, completely, cleanly and sharply. Dot-matrix printers do not meet this requirement.
These colour specifications are merely indications. The decisive factor for machine reading of addresses is ultimately the contrast between the background and the colour of the address. This contrast should amount to at least 40% (ISO 1831). This rules out dark address and barcode zones and coloured address characters.
Optical brighteners/fluorescent and phosphorescent substances
Once it has read the address, the sorting machine converts it into a barcode which it sprays onto the item (envelope or card) with a fluorescent ink. This code can only be read by machine if the background to the barcode is not fluorescent as well. Fluorescent or phosphorescent substances in the colour pigments of certain inks are particularly critical.
Tip: as far as possible avoid using fluorescent or phosphorescent substances which emit yellow or red light when stimulated by blue light. Ensure a minimum 40% contrast ratio between the background and the information to be utilized.
To ensure legibility is impaired as little as possible by the brighteners widely used in the paper industry, the letter-sorting machines stimulate the barcode with blue LED light with a wavelength of 455 nm. This causes the ink used in the barcode to emit light in the 590 nm range. The transmission of a band pass filter used for the emitted light is in the range of 565 - 730 nm.
Writeability/resistance to smearing
Ensure that the sizing of the paper guarantees good writeability and resistance to smearing. This applies both to the alphanumeric address applied by you and to the barcode applied by Swiss Post's high-performance sorting machines.
Tip: uncoated papers and many matt-coated papers have the necessary resistance to smearing.
Colour transfer (so-called "smudging" or carbon transfer)
Nowadays, an unwanted transfer of colour or toner from one paper to another can only rarely be blamed on letter-sorting machines. Items with traces of "smudging" do not affect the machine processing of the item and cannot be detected by Swiss Post either as they appear solely on the content of the mailing. The transfer of colour will only be noticed by the recipient of the item. "Smudges" give the negative impression of a cheap, low-quality mailing.
Tip: avoid "smudging" by using the right paper, colours and toners.
Ensure that sufficient heat is generated in the fixing station of the printer/copier for the toner to be transferred permanently.
Take care with paper which has previously been printed with corporate logos etc. using the offset procedure: offset printing requires paper with a higher moisture content than laser printers/copiers.