Pattern stamp pixels

When you define a pattern, its size is set to the number of pixels you have selected. When applied to different images with the brush or other tools, it will be relative to that document's dimensions. If you select an area that is 100x100 pixels in a 200x200 image, stamping back into that same image will be pretty big. But if you stamp into a 1000x1000 image, it will be much smaller. In terms of quality, it is an exact copy of your original material, so if that was print worthy, your pattern stamp will be as well.

Basically, the Pattern Stamp Tool works similarly to the Clone Stamp Tool, but uses a permanently saved sample rather than one which exists temporarily in the clipboard. That is why they are nested together in the Tools panel by default and share the same tool icon.

Unfortunately, it's a pretty simple tool with very few controls. It doesn't have any of the additional options that Clone Stamp provides to modify scale, orientation, etc. To have any ability to manipulate your pattern, you can use a Pattern Fill Layer and then use masking to emulate how the Pattern Stamp would brush in the pattern. This will provide you with options to change the angle and scale of your pattern so that it may better fit with your new documents.