The Superia brand of daylight balanced colour negative film is aimed towards the point and shoot market but it has also become a go-to film for many enthusiasts. The X-TRA 400 is just one of the variants available. Film speeds for the Superia line are available for 100, 200, 400, 800, and 1600, although these days, you will most likely only encounter 100 and 400 ISO variants.
Meanwhile, the Fuji Superia Reala, initially called Fuji Reala, is a 100 ISO portrait film made for professionals and enthusiasts. Then, there’s also Fuji Press, which comes in 400 and 800 ISO speeds; it has the same emulsions as the Fuji Superia 400 and 800 films, but especially handled and refrigerated after its manufacture.
While Fuji Superia X-TRA 400 makes a good all-around colour negative on its own (even when expired, as long as it’s stored properly), redscaling it also opens up a host of fiery possibilities for your Lomographs. The lower the ISO you rate it with, the less intense the reds and oranges will turn out.
Fujifilm’s dedicated page for the Fuji Superia X-Tra 400 has more details and technical information about this colour negative film.