Mail should be between 0.25mm and 5mm thick. Thickness variation should be no more than 2mm across height or length of mail item.
For maximum quality of service and to ensure that an item will pass through our automated equipment, items should weigh no more than 100g.
Items must be flexible enough to bend easily into an S-shape along the longest edge. Please do not enclose items such as coins, keys and thick card coupons. The minimum flexibility is pre-defined by the minimum paper weight. The maximum flexibility is defined as the force to deflect the mail item (with all enclosures) 5mm when placed between two fulcrums 75mm apart. Maximum 2kg force.
The envelope paper needs to be at least 85% opaque. This will prevent any character of pattern on the inside from showing through the envelope material, preventing our equipment form reading the address.
The paper used for postcards and single piece mail must have a porosity value between 400 and 700 ml/minute. The paper used for envelopes must have a porosity value greater than 400ml/minute.
Ensure the item is securely continuously sealed on all sides, taking care to avoid a residue of gum on the item itself. Please do not use metal clips or staples.
When sending items in envelopes the best colours to use are white, cream or light buff.
Please do not use dark coloured or red envelopes.
Fluorescence and Phosphorescence
The ink used for printing codemarks contains both phosphorescent and fluorescent materials. When passed beneath a high intensity long wave ultra violet light source this ink gives
out a strong light signal, which is read by the equipment. If the mail item contains impurities, our equipment could have difficulty in distinguishing the codemark from the background. The use of brightening agents, particularly within white envelopes, is common and generally does not cause problems as long as they are kept to a minimum.