Vintage china and glassware, or anything of age for that matter, should always be washed by hand, in warm soapy water, and dried with a soft tea towel or cloth, after all, that’s how our Grandmothers and their Mothers did it.
Your vintage items should never be put in the dishwasher. Items with age were not made to withstand the extreme temperatures and harsh chemicals of dishwashers, they were not even thought of when these pieces were made.
One result of dishwashing, if the item survives, is colour fade, especially the blues in floral patterns. I recently received a lovely vintage sweet set and some pretty Johnson plates. Both patterns had the blue sections faded to almost white, a sure sign they had been run through a dishwasher. The items still have a value, but severely reduced, and what a shame to see beautiful items that have been cared for decades ruined, by simply putting them in a dishwasher.
I spend most of my afternoons with my arms in the sink up to the elbows in soap bubbles, it can be quite therapeutic. Save the dishwasher for the cheap stuff that’s easy to replace.