One night in December 2019, Emma Louthan realized in a mild panic that she needed a gift for a child’s birthday party the next day. She grabbed acrylic paint and some of her daughter’s old clothes and began creating an aquatic scene: pink koi swimming beneath white and green water lilies.

The birthday boy wasn’t much impressed by the artful present, but it planted a seed in Ms. Louthan’s mind.

A few months later, she tried her hand at a collection of about a dozen hand-painted adult sweatshirts and found a more appreciative audience. It was the beginning of Covid lockdowns, and Ms. Louthan, an artist in Philadelphia who graduated from Temple University’s Tyler School of Art and Architecture, was working as a freelance textile designer while at home with her husband and 1-year-old daughter.

The sweatshirts, which she had painted in the kitchen of her brick duplex in Germantown, sold out online almost immediately.

“I feel like I just kind of accidentally hit it at the right time,” said Ms. Louthan, 35. Though divisive and terrifying, the pandemic also brought out people’s softer sides. Suddenly, comfort was king. Everyone was baking or crafting. Small-batch ceramics and upcycled quilted coats soared in popularity. There was a compulsory return to the home — and a wholehearted embrace of the homemade.