What makes the colors in Soviet postcards so beautiful?

I don't know about you, but I love the colors in professional Soviet photography from the 70s and 80s, like the ones you find in old postcards. I don't know what causes it, but they look cozy to me, making any district look like home. I wish I could achieve colors like that in my own film photography.

These are a couple of old photos of Lazdynai, the residential district my next video will cover, which won the Lenin prize in 1974.