Originally Posted by
deadlegion
Even though all of Pertwee (3rd Doctor) was colour some episodes were lost and only B&W copies remained.
You might think that's odd, but copies made for stations in other countries like ABC here were just B&W copies.
Tom Baker was all colour copies and nothing was lost.
I think at least one of the early Pertwee B&W to colour restoration attempts involved using PAL B&W with NTSC colour mixed together. I've got a copy here and it looks horrible...NTSC is lower quality so the colours are all blurred.
Might've been one of the Silurians stories but I can't remember right now off the top of my head.