WEIRD Eames shell - brown vinyl (maybe leather)  

one more pic...
one more pic...

Strip
Strip the paint off the back and there will be no gel coat.
I would rather leave the factory paint as is.

I've won many arm wrestling contests in my day but.....
I can't take the cover off. I now see that it's removable but it's really on there!!
Ok ok, I'll use my super human strength.....

I'll bet a coke
it's parchment.

I'll go with
Hot Pink.

Camouflage
In which case it will be worth a pack of smokes.

I have
a dark brown vinyl arm shell with a factory stitched-in brown hopsack seat. It's nice.

barry
Find out what's underneath!!!

Excited to have stumbled upon...
Excited to have stumbled upon this thread. I had a beat upholstered armshell that sat in my daughters room for several years. The stitching was all shot and falling apart. After seeing this thread, I remembered seeing the form that holds on the cover falling of the chair.....and it had the dark grey/black painted back. I had always assumed it would have the drilled out bottom, but had never bothered to look too carefully.
I got home this evening and pulled off the cover. Lemon yellow, I think! Too yellowy to be parchment. Now to decide if I remove the paint on the back or leave as is. Either way it needs the rest of the tape removed and a cleanup. The rubber that went around the outside of the upholstery has left black gunk all along the edges.
Sorry for the crappy pics.
Edit-Pic of back added.

definitely
lemon yellow.

Acetone
Will also remove the gel coat.

I don't think
Acetone will remove the tape residue that easily without harsh or extended treatment, but whatever.
Good luck to you!
I would probably try WD-40 first.

Does anyone know WHY they...
Does anyone know WHY they did these chairs as two tone? What's the point? Although a friend found a pure white armshell with removable cover. The cover didn't have any tape or anything! It came off completely clean. Which was great, because the red vinyl cover was trashed and the shell was mint underneath.

...
"The first upholstered shells, like this one, and we quote from the 1955 Herman Miller catalogue, "come with an applied finish on the back of the shell. Chairs upholstered in blue, black, ultramarine, dark grey, charcoal,or navy have a black applied finish on the back of shell; the backs of chairs upholstered in other colors have an applied beige finish." The upholstery itself is all of one material, naugahyde in this case, held on to the shell by an integral wire, sewn into the upholstery material. At this time they had not yet developed the extruded vinyl rim which eventually was used to secure the upholstery on later shells."
http://www.eamesoffice.com/vintage/worksheet_detail.php?id=7