Ektachrome is a brand name owned by Kodak for a range of transparency, still, and motion picture films ... Ektachrome has a distinctive look that became familiar to many readers of National Geographic, which used it extensively for color photographs for decades in settings where Kodachrome was too slow.
I copied this definition from Wikipedia, but it still left me wondering exactly what Ektachrome's "distinctive look" actually looked like. There is, however, a Flickr group exclusively devoted to Ektachrome, and from that source I drew these examples (which I like individually, but am still not persuaded they hang together visually in anything like the same unmistakable way that Kodachrome images do).
This Ektachrome duck is for Mabel Watson Payne, in honor of her partiality at this time in her life for ducks. She has two bath tub ducks, stickers that are ducks, stuffed ducks, ducks printed on socks, a counting card with a duck family, and several books about ducks or including ducks. When she needs to pronounce "tur-tle" she says it slowly and carefully because it is a difficult word to say, but the word "duck" comes out loud and easy.