Disney first started toying with digital ink and paint in The Little Mermaid, and the Rescuers Down Under was the first fully digital film (which is ironic because the only HD release appears to be struck from film).

At first the data on the CAPS had to be transferred to film and then home video formats. Later, it became possible for Disney to use an all digital pipeline from the CAPS computer to DVD.

Off the top of my head the original Gold Edition of Pocahontas was struck from film and had heavy grain as a result. The 10th Anniversary disc was taken right from the CAPS computer and is a definite upgrade. It should also be noted that the colors are reportedly more accurate on the 10th Anniversary.

The conversion of these films for IMAX was a chore because they wanted to 'improve' the detail in the animation for the larger projection format. This involved touching things up and adding new detail. Animators were involved not just technicians making the transfer.

I only pretend to have a good understanding of this, but last I heard Disney only has one CAPS workstation still in service. I would hope that isn't their only way to get the data for new transfers, but it is apparent that they keeps some sort of digital master.