4/0 : Full colour front only
4/1 : Full colour front with a black reverse
4/4 : Full colour both sides
5/1 : Full colour with spot (or metallic) silver (PMS 877C) front and black reverse
5/5 : Full colour and spot silver (or metallic) silver (PMS 877C) both sides
Standard refers to business cards that are 90x55mm, 90x50mm or 86x55mm (finished trimmed sized)
Slimline refers to anything other than our standard business cards sizing but larger than 30x30mm (no larger than 90x55mm)
