I'm not from that generation, but I know both Kodak and Agfa had orthochromatic films on the market, Agfa still makes it (now under Rollei Ortho 25 trademark).
Many famous Elvis Presley portraits were done on orthochromatic films. Or the iconic pic of the
Union Jack on South Magnetic Pole, 1908. I find the modern day Ortho 25 does have
certain tonal qualities that aren't acheivable by using just a blue filter on a regular full spectrum film.
Well it means precisely that - reducing image quality. I have tested many filters and I could tell WORLDs of quality loss using cheap to medium price-range filters on my own photos, i.e. the popular Cokin pro line filters that visually soften the sharpness, especially the corners, introduce unwanted color casts (especially their NDs and GNDs) and as with any filter you lose light-power (it's around 4% loss on each surface the lightbeam has to pass, multicoating reduces it, but it's still a loss - i.e. if you have 2 completely clear filters non-coated in front of a lens you'll already lose around 16% of the light). Also if you use two or more low- or medium pricerange filters the results often render just visually softer in sharpness compared to a non-filtered shot, add reduced contrast and degraded midtones wise, horrible glow when shooting against the light. I've been there and done that, started with the cheap filters thinking it's a smart move but and constantly dissapointed with results I've kept buying the better ones, and ended up with the high-ends.
IMHO, unless you look for lo-fi only high-end filters, multi coated and made out of high quality glass preserve more or less the IQ one would expect to, and only if you use 1 max 2 filters at time. I've tested them all the way from cheap to high ends and ended up using now Lee (GNDs, non-coated), B+W and Heliopan filters (all multicoated versions), and I find even those very expensive filters can degrade image quality in certain conditions, i.e. shooting against the light or using them on very wide angle lenses (reducing corner sharpness).
Cheers,
Margus