Leafing through a book of his paintings, the robes worn by his models are the same from painting to painting, and become increasingly worn and torn as time passes. And after using this painting as a model, I believe that it's painted almost entirely in earth colors, with little or no vermillion or lapis. The blue of the virgin's gown is dark, possibly just a bit of azurite with black glazes. I don't know. I used ultramarine which was way too bright and I had to tone it down with glazes of Mars black. The orangey red is easily imitated with glazes of red ochre or red earth, such as Pozzouli Red. It's not vermillion. He must have been very poor when he painted this. Apparently he fell on hard times in later life due to religious conflicts with authorities which dried up his patronage. In spite of this, the colors glow.
I based my composition on the Karlsruhe crucifix, but it is much larger than my painting. I'll have to check on the dimensions. [The Karlsruhe Crucifix measures 195.5 cm x 152.5 cm. My panel is 45.4cm x 30cm].
Here is another Grunewald crucifix that is somewhat smaller [This painting is from abou 1513 and measures 75cm x 54.4 cm so it is still a bit larger than my panel] and has a more comparable level of detail: Well, you can't see much, but the faces have less detail. The robes of the female figures have less fully-realized fabric folds, although St. John's robes are beautifully rendered, and the armor of the saint on the right is highly detailed.
I'm going to my studio tomorrow and pick up some stuff, including all my preliminary sketches and the photos I took.