I've addressed this subject on the forums in years past, but wanted a version of my argument on the blog for posterity's sake. Back in 2009 and earlier when I first started painting these people used to paint the part 3/4 masks a variety of colors due to the fact that the masks look so different in the films. Were they white? Beige? Yellow? Sandshell? (lol), or something in between? Since then hock painters have standardized their color into a light lemon yellow color, which I believe to be inaccurate, as I will explain.
For starters, do not trust what you see in the film. Lighting can affect the appearance of the mask, as can color timing in post production. So how do we really know what color it was?
Well back in December 2009 I asked Robb Wilson King, the art director who worked on Friday the 13th part 3 and painted the originals. He described it as a "cream color" created by a "slight aged patina" over an off-white base. I took this to mean that the "cream color" was some sort of translucent glaze designed to give the mask weathering some depth, but can't be sure.
Regardless... as you can see from the several behind-the-scenes photos below here the mask wasn't exactly yellow, although there were yellow undertones in the color that will emphasize in certain lighting conditions. It was a sort of caramel-beige color. Call it a "cream color" if you like. My own approximation of it is at upper left.
Some painters have alleged that the mask changed colors over the years. But the above photos were taken between 1982 and 2010 or so. They all show the same color. So this theory is false.
This is the color I used to paint my masks. It took tons of trial and error to get it right with an acrylic mix but I think accuracy is the way to go. There was an acrylic color called "camel" at Joann Fabrics they used to sell that was extremely close. So there you have it. The mask may have looked white onscreen in certain scenes if the beige layer was translucent. Perhaps Dario Latinovic, who owns the part 4 mask can shed some light on this.
Update: Need more proof? Jesus Christ you're stubborn. Here you go, Dario with the real thing. It's beige, not yellow:
If you're a hock painter and you want to achieve this color, go get this and basecoat away: