That line is the seam of the Scotchlite reflective tape that the blade rods were covered with. It shows up depending on which way the actor is holding the prop. The Scotchlite material reflects light the same way, whether it is spinning or sitting still. The rods were round with flattened sides, not square.
They kept breaking on New Hope so were never used on Empire.
Clearly not the seam of the reflective material. I was under the impression that at least 1 side of the squared rod was colored black to give it a flickering effect.
As an average fan with a fancy for for Star Wars props, I've heard a few things in interviews, I also heard a few things on this board. It's all mixed up in my head so I have no idea what info is fact and what is speculation. I know this sounds bad but I also tend to take those who made the original props with a grain of salt because I simply believe that for the most part it was just a job for them and they never thought much about it until many years later when asked to recall the details. In short, I think their memory could be sketchy.
Anyhow from what I heard over the years is basically what Kurtyboy has stated. Flat side rod with at least one ( I also heard two opposite) side(s) left unpainted. The reflective material I heard was used was that used for projector screens. Since it was stated it was painted, I am assuming it is the paint used for projector screens. I was told the rod was square. I guess that can mean four sides but I also am open to believe it could be round with flat sides or square with round ends.
One other thing I heard that I never saw proven was that one side of the painted side was not painted at the top 4 inches to give the blade a flicker upwards as well. However from the pictures, it looks more like the top 4 inches of the blade are completely covered one all sides as to not have any flicker in that area. But hard to say, for all I know, it could be dark on a side I cannot see.
Historically I was led to believe that the blade was going to be a total practical effect. The rotoscoping was only done when Lucus was not happy with the practical effect. They said on film it looked like what it was... reflective material on a spinning blade. I can only assume that originally the blades were all going to be white, but as stated, I am assuming. Anyhow, it would be logical to believe that since that spinning rods were no longer key to the effect, they no longer utilized flat sided rods for that reason and not because they were breaking. From what I understand, the carbon rods used in The Empire Strikes Back and Return of the Jedi did break and not only that, emit dangerous shards. Which is why they opted for plastic wrapped aluminum rods in the prequels. Safer to bend rather than break.
...ok.... That's what I have heard/recall. I have no idea how much of that is correct. Nevertheless, a really interesting topic.
Where's Lonepigeon? He always has something insightful.
