A Japanese snackmaker is simplifying packaging as a naphtha supply squeeze hits printing ink. Bloomberg/Getty Images A popular potato chip maker in Japan is turning its snack bags black and white due to naphtha shortages. Prices of naphtha, a raw material for printing ink, have soared as the war in Iran is squeezing supply. The supply squeeze is hitting companies across Japan, including toiletmaker Toto. First, fuel prices surged. Now, even potato chips aren't safe from the global petrochemical squeeze. In Japan, snack giant Calbee — known for its popular potato chips — is switching some colored snack packaging to black and white after oil shortages linked to the Iran war squeezed global ink supplies, local media reported. The culprit is naphtha, an oil-derived chemical used to make solvents and resins for printing ink. Naphtha is also a key ingredient in plastics, packaging material, and adhesives. Prices for the material have surged amid the conflict in Iran.…