The poster thing started, because we thought about something we can create from the already existing wallpapers, but is not as usual as sceensavers and the like. Although, a very simple idea, presenting the wallpapers in a printable format to use on your walls, not many people offered this on their sites.
We had to learn that it is not easy to find a tool to create high quality PDFs that are worth to print and stick together. In the end we found it. Although, we did a lot of tests in normal printing mode of inkjet printers to get the right configuration. As we always work with highend printers, we tried to "simulate" a private users' printer quality without loosing too much quality. In this context we also had to have a look at the created file sizes.
As we reside in Europe we use the Din A4 paper size to separate the images.