There are three types of animation cels. Production, Limited Ed. & Sericels. Production are the cels that were made for the actual cartoons. They were story boarded then hand drawn on paper. The paper drawings were then made later on by printer to create a black line. These were then sent to Korea, China etc to be hand painted. In a normal cartoon there may be 60,000 to 80,000 cels. Most are just eyes, hands etc and stacked to create an image. Of all of these less than 1000 are what you would consider contactable. The pencils were usually destroyed until the end when they figured out people would buy them.
Now all the cartoons are made by computer so no more cels.
The collectible part of production cels is the background. There were maybe 50 made all hand painted and reused for the entire cartoon and sometimes multiple cartoons. When Warner Bros. started selling the cells they would take photos of the backgrounds and use those with the cells. Then get thousands for the backgrounds, when there was a market. The Batgirl cel is what looks like 4 separate production cels taped onto a photo background. These sold for abut $600.
Next are the limited editions. These were usually hand painted and numbered in a series of 500 to 2500 and signed by the creator or producer. Some go for lots of money. Like The Grinch below. I think that one sold for about $2600. These sold usually more than the production cells unless they were original Disney classics.
Last are the seicels like Michigan J Frog below although he is signed, Tweety is not. These are machine (copier) produced, sometimes numbered go give perceived value. Made by the thousands but relatively cheap.
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