"The Black Cauldron" provides us with "Exhibit A" of the disorganized nature of the Disney organization from the mid-1970s through the mid-80s. The company's feature films were attracting smaller and smaller audiences, and no real creative force had emerged since Walt Disney's death in 1966. By the mid- to late-70s, it was clear that new ideas needed to be tried. The phenomenal success of "Star Wars" appeared to offer a sure-fire way to box-office success: sci-fi/fantasy movies. At the same time, Disney Studio's full-length animated features continued their descent from the heights scaled in 1959's "Sleeping Beauty", at first downscaling the subject matter, then progressing to less and less impressive animation, and finally combining the first two trends with boring storytelling (see "The Fox and the Hound" - 1981).
It was in this context that pre-production began on "The Black Cauldron" in the late 1970s. From an artistic standpoint, its goals were two-fold. First, the film was to recapture the lead in animation quality that Disney had traditionally held, while the second goal was to incorporate the advances in animation and subject matter made in the 1970s (i.e., playing "catch up"). Some early decisions were good: the source material was top-notch. Lloyd Alexander's "Chronicles of Prydain" are fantastic works of fantasy for the young adult - I loved them as a middle-schooler in the mid-80s, and the choice to film the story in 70mm widescreen harkened back to the glory days of "Sleeping Beauty." Unfortunately, not much else worked. The studio's writers did a terrible job of condensing the first two books of Alexander's series, and we end up caring little for the characters that emerge, or for the plot as it unfolds. Also, the movie's tone is uneven. Overall, the work is very dark and un-Disney, which would've been fine had it been executed better. Further, the grimness of the plot doesn't mesh with occasionally clumsy and earthy attempts at humor, and the character animation fluctuates between sober naturalism and exaggerated, cartoonish mannerisms (stretching ears, gaping mouths, etc.) Still, some of the shots are stunning and rank among the best in the history of hand-drawn animation (e.g., multiplaned exterior shot of the Horned King's castle, beautiful backgrounds within the same, Hen-Wen's capture by the Horned King's creatures). The result of this mish-mash was a box-office flop ($25 million to make, $5 million in ticket sales upon its 1985 release).
In short, see this film for its often-impressive animation and intermittent charm. Be sure to get the newly-available widescreen version on DVD. Bemoan the end of the era of stunning hand-drawn animation (Disney has closed up its shop; "Home on the Range" was its penultimate hand-drawn feature). Don't expect a classic, but appreciate the vision of its artistry - even if the final product didn't quite mesh satisfactorily. "The Black Cauldron" is a noble failure.