What are lined paper envelopes?
Some paper envelopes are “lined” on the insides. This means that there is printing done in dark colors on the inside of the envelope. This prevents the contents of the paper envelope from being seen when held against the light. Most business envelopes are lined to protect their contents from being seen. Usually the lining is done by printing a heavy mesh of lines in dark blue or black color. Other paper envelopes like invitation envelopes can be lined using custom colors or foils and prints for example gold or silver foil lining for wedding invitation paper envelopes.