John Romita Sr did not concern himself with using art materials that would best display his art for the collector aftermarket of today. Instead his concern was how slick the ink would look on the published Marvel comics finished product. To that end a lot of his originals were drawn on vellum instead of board. Vellum is a transparent paper that allowed him to see over his pencils as he was drawing and gave his inks a polish that they lacked on regular board. My understanding is that the regular board absorbs the ink to a greater extent. The lighter transparent vellum allows the ink to roll better on the paper which gave Romita more control. The vellum piece, once drawn, was then glued down to a cover board which over the years in many cases has caused the cover to yellow or brown in tint. The upside is Romita created some absolute classics with this technique. The downside is many of his great covers are not on board--the preferred collector medium.
A good restorer, in some cases, can bring a vellum board to look almost as good as a work on regular board. But for the most part, collectors tend to view the vellum pieces as less valuable then their board counterparts. In the past I've managed to get some very nice vellum Romita covers at far less than they would have cost on board. But when it came time to sell them they always seemed to move for less and slower than similar board covers. In addition to the way the cover looks, some collectors feel that the lack of pencils underneath the vellum also brings the price down. Generally speaking the vellum acts as tracing paper and the pencils are left behind on a separate paper after the ink is put down on the vellum. Board covers tend to have the pencil underneath the ink on the same piece of paper--you're getting both the artist's pencils and inks.
With the recent rise in prices I wonder if this type of prejudice will continue or if vellum covers will come to be more accepted by the collecting community in future. Here are a number of vellum covers that I owned, or considered owning, at one time or another:
This cover, Conan 30, is one of the few vellum examples I've owned not by Romita. The bat was drawn on vellum by Ernie Chan to create a visual effect on the published cover. While this is not truly a vellum cover as the rest is drawn on board, the darker discoloration of the bat made it less desirable.
Here you can see the cover after restoration lightened up the bat to make it better fit with the overall color of the cover.
The Avengers 119 cover was a favorite of mine. It was very brown when I had it restored. I kept it for a number of years and made a slight profit when I sold it. Had it been on board I could have sold it for much more as comparable board covers had doubled in price during my tenure of ownership. This can be the opportunity cost of owning a vellum cover if not purchased at a discount price.
On the other hand the ASM 145 cover was fairly inexpensive and I was able to trade it for quite a bit more. It cleaned up very nice after restoration. You can barely tell that it's a vellum cover. In this case the image was so dynamic that I think it trumped the vellum and allowed for me to make a really strong trade.
The Sub-Mariner 69 cover was purchased a couple years back. It was inexpensive due to the title and brown coloration of the vellum.
After restoration it looks quite nice. I haven't tested it's price on the market as I've decided to keep this beauty in my collection. The disco Sub-Mariner outfit designed by Romita is a personal favorite.
A stunning Romita Luke Cage cover I had restored. It took me a while to move even after this fine job of restoration.
The Invaders 1 cover is a personal favorite that I would have loved to own. But I felt it was too expensive at the time it was auctioned off. The vellum kept me from stepping up on a price that I felt was too high. I thought I would never get out of it if I ever needed to.
A classic Romita Vellum cover. Never owned, just admired.
The Spec Spidey 1 special edition cover--another vellum cover that looked great after restoration. Still it took me quite a while to sell and at a price that wasn't very different then what I paid for the cover initially. The vellum, I feel, hurt it's resale chances for me.
I'm wondering if vellum is still the turn off it once was...or if today's collector sees it as an opportunity to get a really cool cover at perhaps more of a bargain price. Or does vellum not matter to you at all as long as you get the image that you desire? I think vellum is still a factor the collector HAS to consider when paying top dollar for a piece. After all, you don't want to get stuck with an expensive piece you can't move do you?