"But that blob's not present on every frame of those scenes, is it? Are those the first frames of those two shots? If so, maybe it's something to do with the way they film was originally spliced (there were all kinds of jumps and scrapes and rubbish on first or last frames that I cleaned out of my LD transfer, which weren't there when I got the 2004 DVDs to use as source)."

http://img95.imageshack.us/img95/7084/esbblobrp2.jpg

"I think I'll go with splicing glue."

That's precisely what it is, and it only occurs between certain scene changes (some are worse than others.) Believe me, I know. What do you think I've been removing from individual frames for the X0 Project?

They are mainly yellow in ANH, but I've not gone through ESB at such detail. Apparently, they used a better (read: clearer) glue for some shots, but the above shot looks like it would in ANH.