TOKYO (AP) — The packaging on some snacks in Japan is turning a somber black-and-white, as the war in Iran disrupts the supply of an ingredient used in colored ink.

Tokyo-based Calbee Inc., which makes potato chips and cereal, said what's inside remains the same. Calbee's popular snacks are available in Japan's omnipresent convenience stores and shipped to the U.S., China and Australia.

"This measure is intended to help maintain a stable supply of products," it said in a statement this week.

The change on 14 products in its lineup will start May 25, limiting ink colors to just two, the company said, noting it was necessary to respond flexibly to changing geopolitical conditions.

How long the change might last remains unclear, according to Calbee, founded in 1949, and employing more than 5,000 group workers.

The move is the latest caused by the effective closure of the Strait of Hormuz because of the war in Iran. The war has sent prices of oil and other products higher, as well as caused supply crunches.

Japan relies almost entirely on oil imports. A key oil-related product called naphtha is used in various items like plastics and ink. Japan has so far ridden out the worries relatively calmly, as the government has worked to allay such fears by noting the nation's oil reserves.

But there's no mistake in the stark change on the chips packaging.

Calbee's lightly salted chips, known as "usu shio," originally came in a bright-orange bag with an image of yellow chips and a potato-man mascot wearing a hat.

The new packaging just has monochrome lettering.

The company, which also makes shrimp chips, or "kappa ebisen," had just announced an ambitious growth strategy in March.

"Calbee will continue to respond flexibly and promptly to changes in its operating environment, including geopolitical risks, and remains committed to maintaining a stable supply of safe, high‑quality products," it said. "We ask for your understanding."