Some interesting theories, and I wouldn't go so far as to say that the dome doesn't play into it. Where the dome is placed, how high or low down is definitely a factor. But the biggest factor is how the eyebrow faces are painted and the color of the lenses.
The ANH eyebrow faces are painted black.
The ESB's are fully highlighted.
The ROTJ's are only partially highlighted.
I did this thread because I had spent a bunch of time trying to decipher Vader's eyebrows. In some pics they were very broad and solid, in some pics they were thin and sharp and in some pics you couldn't see them at all. I was trying to detail a helmet and was getting very frustrated because every time it seemed that I matched one picture, it would totally disagreed with the others.
My first mistake was, thinking that they were all the same.So I spent a bunch of time studying pictures that I had, trying to solve the problem. And then one day I noticed something. And once had I noticed it, it was a matter of going back and seeing ifwas this really the case or was it just this pic making it look this way? But now that I knew about it, I could literally see it in every single picture. It was obvious. I was working on an ANH helmet but every time I painted it, it looked more like an ESB or an ROTJ. What I had finally realized, was that the faces of the ANH eyebrows were painted black, just like the underside of the eyebrow. Why this was done, I cannot say. I can only guess, that maybe George had looked at it, with the helmet as low as it is on an ANH and said, if you're not gonna see the entire eyebrow you might as well just paint it black. But it is painted black. Likewise, most ROTJ helmets have eyebrows where the bottom 75% of the brow face is painted black, highlighting only the upper edge and thus making the eyebrow look sharper and more angular. The full eyebrow is still there in all its thickness, you just can't see it, because of the black paint. Only the ESB's and two ROTJ's have fullface highlighting on their eyebrows.
The only reason I did this thread, was because I had noticed many people doing ANH helmets, and bending over backwards to get details like the C scar and the brush painting down correctly, yet the look was thrown off by the helmet having highlighted eyebrows.
Some people want to have the highlighted eyebrows and that's fine.My only hope was that people would go back and look at the pictures for themselves and see that the eyebrows were painted black.
But if the eye brows were actually highlighted, the pictures would look more like this. The dome is tipped up way more than enough to see those eyebrows.
Take the pictures below. The picture to the right is the original. I did nothing but lighten it up. But as bright as it is, you still can't see the eyebrows and the dome is sitting as high or higher than any ESB. I did not just draw in eyebrows on the other picture, I duplicated the picture, then
highlighted it until I could see the eyebrows, isolated them and then duplicated them, then transfered them back to the original picture and used a little Photoshop to blend them in. Yet that image looks completely natural as if the helmet always had highlighted eyebrows.
The ANHs also have a somewhat more reddish tint to the eye lenses.
I did the same with these pics, only in this case, it's the pic on the left that's the original. All of these, only to illustrate what the difference would be if an ANH had highlighted eyebrows and help you see the black on the eyebrows in the original pictures.
So you still want to highlight your eyebrow faces, go right ahead. The preference is yours. Only if you're trying to make a screen accurate version you should paint them black.
There is no questioning about the highlighting on the ESBs. They are actually what everybody tends to think the eyebrows actually look like. However, they are really only that way on the ESB and two of the ROTJs, one of those being the reveal, and not including the 'Luke help
me take this mask off' helmet, which everyone knows is an ESB. The ESB's also have a more brownish amber color to the lenses.
The ROTJs. As these images clearly show, the apparent sharpness of the ROTJ eyebrow is an illusion created with paint. As far as I can tell there has been literally no modification to the eyebrow itself at all. It should be noted that the helmet in the second picture was not color
sanded prior to the application of black paint and so it has a severe issue with the black paint peeling and the black has peeled off the far eyebrow face leaving the highlight color which was painted first. The other slight difference with the ROTJ helmets comes from the eye lenses,
which are slightly flatter than their ANH an ESB counterparts. They also appear to be tinted gold. Whether this is achieved with a mylar applied to the back, or perhaps a metalizer paint sprayed on the back is unclear, but this tinting can be seen even in frame caps.
If you should feel the need to physically create this sharpness to your ROTJ brows, go right ahead. It's your preference.