Dumbledore stroked his beard leisurely, his eyes glinting with thought, and began slowly:
"After investigating it for some time, I have gained a general understanding of how Muggle films work. They simply project a rapid succession of images, creating something called visual... visual..."
"Persistence of vision, sir!" Dobby interjected eagerly, his eyes alive with the desire to prove himself.
With a kindly smile, Dumbledore gave Dobby a small nod, then continued his explanation at an unhurried pace:
"Memories, however, are more precisely the visual manifestation of thoughts. They are already continuous combinations of sound and images. If we break them into individual images and then attach them to film, we would not only be losing sight of what matters, but also greatly increasing the burden on those making them.
"Moreover, from what I know of various materials, film capable of holding memory substance would require rare materials such as dragon hide fibers and unicorn hair. This would undoubtedly raise costs considerably.
"We might instead turn our attention to crystal balls. Though commonly used for divination, crystal balls actually have the potential to be modified for memory storage.
"We could use Memory-Injection Magic to inject memory substance into specially treated crystal balls. These crystal balls contain magical liquids, such as a wondrous solution carefully blended from Veela tears and potion ingredients. This can interact with memory substance in remarkable ways, allowing memories to appear within the crystal ball in a form that can be seen and heard.
"But this is not a perfect solution, either. Its drawback is that the memory images can only appear inside the crystal ball or on its surface, and only one person can watch at a time. Of course, most importantly, it is rather costly, as well as cumbersome and inconvenient to use."
Having finished, Dumbledore