In his mid-1800s book, Field described Rose Madder as creating, "…the most perfect carnation tints known." Four modern oil colors are currently made with this vintage pigment but, be aware the methods for the manufacture of this color can vary tremendously. It's related to natural Alizarin Crimson, pigment NR8.
Though this is a lovely historical hue, it isn’t wholeheartedly recommended for use in artist paints due to lightfastness and permanence issues. However in a historical turning-of-tables, in oils, it may actually be more lightfast than the synthetic versions of madder e.g. PR83 which were said to replace it. For more, reference the lightfastness testing done by Virgil Elliott. Interestingly, back in the 1880s, Field seemed to agree, as he wrote, "Not liable to change by the action of light."
Once upon a time, we had a vintage tube of oil paint which was the pink variety of Rose Madder made by Winsor and Newton. It had a sort of "glazes only" quality and was unlike any paint we’ve ever seen. It was sometimes streaky but a rather high chroma pink (nothing like PR122). Something like a milky transparency, a transparency in masstone. The light gets around the edges when looking at in masstone, and this pigment shows that filmy note.
Depending on exactly how it is manufactured, its properties may vary. Cameo tells us that madder may refer to one of several plants of the genus Rubia. Rubia tinctorum L. is the most common but Rubia cordifolia L., and Rubia akane Nagai are used as well.
Pigment NR9 is sometimes called Alizarin or Purpurin (genuine Madder Lakes contain both Alizarin and Purpurin), and there is some interesting literature on how the purpurin fades out (weirdly, despite the resemblance to the color name purple, purpurin is an orange color which is fugitive). Cameo states, "The most important constituents are alizarin (red) and Pseudopurpurin from which Purpurin (red) is formed …", and elsewhere in the entry for Rose Madder specifically, they state, "The colorant was extracted from madder roots with an acid, then the precipitate, primarily Pseudopurpurin, was redissolved in alum then precipitated with Calcium carbonate (chalk) to produce a pink lake," citing Artist Pigments vol. 3.
Reports on the lightfastness of natural madder in oils vary tremendously. Virgil Elliott reported that Winsor and Newton’s genuine Rose Madder and Rose Madder Deep oil paints were more lightfast than Alizarin Crimson PR83 in his tests. He also noted that the thickness of its application may affect its permanence and that it may fare better unmixed and at full strength rather than a glaze. How this pigment is manufactured as well as the precise process may matter a lot. Some vintage paints in oils from Winsor and Newton are surprisingly beautiful with a filmy/milky pink consistency. However we would not rely on this as a lightfast pigment. Agreement is pretty uniform that genuine Rose Madder fades.
Rose Madder requires a high amount of oil to turn it into an oil paint and tends to be a slow drier.
Strangely, this pigment may be closely related to cancer-causing anthraquinones. While acute toxicity is thought to be low, it may also cause allergies. Monona Rossol's pigment data sheets, available through her site, contain more information. Treat all pigments and paints with studio safety protocols.
