EDIT: Oh, wait, holy shit. This ribbon is multicolor — you can see the red stripe on the ribbon, and apparently the Remington Travel Riter Deluxe does support multiple colors on a ribbon.
I think that it’s the lever in the upper right on the front that switches color.
EDIT3: You know, decades ago, I remember fiddling with my dad’s typewriter. It had a selector lever there too. Could never figure out what it was for, seem to recall that it adjusted the height of the hammers, which seemed pointless. He only had a black ribbon, but I bet that it supported a multicolor ribbon, and that’s what it was for. Never did resolve that mystery until now!
I’m pretty sure there should be colors there
It was either red or black, and Arch definitely doesn’t use red in its branding.
That typewriter probably doesn’t support color, but apparently some had a ribbon with multiple colors and the ability to select among them.
https://old.reddit.com/r/typewriters/comments/1jnie9o/can_someone_pls_tell_me_why_my_typewriter_has/
This guy is using it to do color accents with typewriter art:
https://www.youtube.com/watch?v=_bqi2qY918M
EDIT: Oh, wait, holy shit. This ribbon is multicolor — you can see the red stripe on the ribbon, and apparently the Remington Travel Riter Deluxe does support multiple colors on a ribbon.
https://www.ebay.com/itm/133756651478
EDIT2: Here’s the manual:
https://site.xavier.edu/polt/typewriters/RemingtonRandTravel-RiterDeLuxe_Manual.pdf
I think that it’s the lever in the upper right on the front that switches color.
EDIT3: You know, decades ago, I remember fiddling with my dad’s typewriter. It had a selector lever there too. Could never figure out what it was for, seem to recall that it adjusted the height of the hammers, which seemed pointless. He only had a black ribbon, but I bet that it supported a multicolor ribbon, and that’s what it was for. Never did resolve that mystery until now!