Holy cow:

“As previously reported the transfer proved a difficult technical challenge, even more so than the HD transfer of the original series. CBS had to return to the original film negatives - encompassing 25,000-plus reels of footage - and edit the episodes together precisely as they were when they originally aired. All visual effects had to be recompositioned digitally, no ‘up-conversions’ from video.”

(via “Star Trek: Next Gen” Blu-ray Trailer Hits | News | Dark Horizons)