I found an article that goes into detail about Super35:

“Next, you can’t make the image too dark when you’re doing your answer-print timing. It’s better to be a little light at that point. Then, when you’re doing your formatting to anamorphic at the IN stage, you’ve got a nice fat IP to work from.”

According to Carpenter, Titanic’s IP, like that of True Lies, was made at CFI on Kodak’s 5244 intermediate stock, utilizing a wetgate direct-contact printer at full aperture, running at 180 feet per minute. A precision ground-glass was used to focus the image through the liquid, while fine-grade filters made overall color compensations. The 2.35:1 anamorphic squeeze was not made at this point, as the IP would also be used to make prints in other aspect ratios.

Source: http://www.theasc.com/magazine/dec97/titanic/pgs35/pg1.htm