The printing spec depends on the exact pressing and printing machines to be used. For replication and silkscreening our 22mm to 116 mm spec is usually correct.
Today we he have a wide variety of inkjet printable media. The print spec for inkjet is usually 22mm to 118mm.
Silkscreen jobs are best done with 2 or 3 Pantone colors. Offset jobs are always 4-color CMYK (photo-quality).
Although we recommend against using photos on a silkscreened disc label, these days most art comes in as a Photoshop file instead of Illustrator line art. We can use almost any image that is at least 1400 pixels wide and high. We'll crop the inside and outside circles to fit the press. The one exception is monochrome bitmap (1 bit) images which should be at least 6000 pixels.