Interesting to know the VEF factory in Riga produced photographic paper as well. Or, they perhaps were the resellers, I do not know for certain. It looks like the film envelopes mention Minox film, and it could be that they sold photographic paper, given the connection between them selling also Minox film in the metal cassettes.
The photo here is of a leaflet which was shipped together with the pack of paper; alas, the text is in Latvian I believe, so not great chance to read it and understand it. However, several chemical recipes can be made out of the text, and this is probably to the benefit of the users.