These envelopes are very good for use with a5 paper. They feel very sturdy and durable, and they hold up in the mail very well. I've used sealing wax with them as well, and they work fine with that too.Writing on these envelopes is very nice, though they feather some. I haven't had any issues with them bleeding though. My problems with these envelopes are that they have a liner in them. This liner helps to stop bleeding, however it has pealed away from the outer part of the envelop, and it catches whenever you try to place a letter in the envelope. I've fought with this liner from minutes at a time whenever I go to send a letter. I finally have decided to trim the liner wherever it pulled up, which works to a point.