This is an intentional background print of small dots surrounding a larger pattern.
In traditional block printing, the dotted design is created by nails driven into the wooden blocks in a secondary pattern beyond the main carved pattern area. These pick up small amounts of dye that transfers as spots at the same time as the block is pressed down to make the main pattern.
Picotage, as the secondary pattern is usually single toned, one of the least dynamic selected from the main palette.