CatBus said:

If you had the OCN, why on earth would you bother to use the tech IB?

My understanding was that the original camera negative for star wars is damaged through over use of making prints/the poor stocks that went into it/time decay, so any prints struck from it now reflect that damage. Whereas the tech IB was struck early in the lifespan of the OCN and has a special dye which protects it more from fade (and possibly why it makes the print thicker and harder to transfer or something?). I also read the colour separations for star wars are also missing sections or something. Therefore in this case the tech IB would be the best record of the original look of the film. George Lucas showed his team his personal ib tech print to the team making the special edition and said this is what it should look like!