As Canada prepares its next round of countermeasures to U.S.-imposed tariffs, some independent art supply stores in London say they expect to be caught in the crosshairs. 

The Government of Canada is finalizing its list of $125 billion in U.S. imported goods that will be subject to tariffs, including art supplies such as paints, brushes, markers, textiles and photography materials. 

However, unlike groceries, art store owners and employees say it's much harder to stock their stores with Canadian …