My Cart

Envelope Manufacturing Flat Sheet Conversion

Flat Sheet Conversion

What is a Flat Sheet Conversion?

Flatsheet converting refers to the process of creating envelopes from sheets or rolls of paper. The paper is converted by being die-cut, folded and glued to achieve the finished envelope. Usually envelopes that are created by flat sheet conversion are for consumers that have a specific need that cannot be met with a stock envelope.

When is this method used?

Full-Colour Envelopes

Often envelopes used for promotional purposes involve full-colour images printed on both sides. With pre-converted envelopes, the seams can cause issues with the accuracy of the printing, therefore it is best to print these onto a flat sheet before they are converted into envelopes.

Non-Standard Sizes

When an envelope with non-standard dimensions is required, either to create an attention-grabbing direct mail piece or to fit awkwardly shaped contents, a flat sheet convert is used to cut the perimeter of the envelope with a custom-sized die before being folded and glued.

Non-Standard Windows

Sometimes envelopes will require non-standard sized, or even multiple windows. By custom converting them, any specific requirements can be met.

Custom Opaques

An opaque is the repeating print on the interior of an envelope which is designed to engance the security of the contents and prevent any confidential information from being read through the envelope. Some businesses and organisations may require a custom opaque. Printing on the inside of a pre-converted envelope is not possible so this has to be done beforehand by a flat sheet conversion, then made up into an envelope.


When an embossed image is applied to an envelope, this creates a debossed image on the reverse side. To avoid this, envelope embossing is often performed onto a flat sheet before being made into the finished envelope.


If you have any questions, please get in contact with our helpful sales team here.