It seems that the companies have all gone to stickers. I have thought that stickers are cheap and the inventory control of tins is better. I buy Chinese tea in metal tins that are painted. Maybe having lids painted like they use to be would be a good side business. More money to China .
It was an offset printing process, where the dry powdered silicates were applied to the tins, and then fired to melt the enamel into the metal. It's very expensive, with a high degree of mess-ups. I see a new process is being used for those fake antique enameled signs and the new cookie tins that you see at Christmas. This is a cheaper process where the metal is actually printed with digital printer directly to the metal. So, something similar to the old enameled tins could be made cheaper than they used to be. But, then the problem is that, "is it worth it to change?" To me, the tins is merely the part that gets thrown away. Keeping them is something akin to a mental disorder like hoarding.