cels
Given the fact that the cells used to make the animated film are likely to have been done on an unstable plastic and will degrade and deform if left in the light and heat, it is worth asking whether new developments in digital reproduction can be employed to make replica cells to go along with replica backgrounds, for framing while the originals are stored in a cool, dark place. As the cells age their clear substrates become more warped, which brings the paint used to create the character closer to the back ground, and if they touch, the paint is likely to stick to the background, since those paints have components that make them tacky, to get them to adhere to the clear material.
Unfortunately, the original cells are the most valuable and the most at risk, so framing a replica is the safest option.
Hugh