Dyes used to give sensitivity to red light
Erythrosine was used by du Hauron in 1878 to produce the first color photographic print using cyan, magenta and yellow. This dye barely sensitized the emulsion to red light--mostly it sensitized it to green. Consequently the exposure through the green filter was for twenty seconds or so, but the exposure through the red filter (actually orange) was for as long as three minutes.
A discussion of ways to sensitize emulsions can be found in a book which is available for free online, E.J. Wall's "The History of Three Color Photography" (1925), here:
Read his chapter on "Color-sensitive Gelatin Plates". He discusses two good candidates: ethyl violet; and pinacyanol blue. Ethyl violet, IIRC, was the sensitiser used in Autochrome screen plates. It produced passable reds although not as sensitive to deep red colors as more modern emulsions. Ethyl violet is available from Sigma-Aldrich, 25 grams for $39.90.
The other likely candidate is pinacyanol blue, aka pinacyanol chloride. This is available also from Sigma-Aldrich, a quarter of a gram for $20.20. Besides Wall, see US patent 2047022. There are other dyes, consider cyanine. I understand that Malachite Green tends to fog film, but Wall does mention it in one recipe.