I am new to LCC profiles, but after today's outting, I have several questions. The sky was blue and I used a polarizer. I created an LCC shot for each shot in which I changed the shift. I shot the LCC by slowing the shutter speed three stops.
If you mean that you've exposed 3 stops more than an average exposure reading, it may be a bit much. I usually use something like an exposure adjustment of +2 EV. Make sure that the LCC is exposed to a bright level, but not clipped.
When I applied the LCC profiles to the the images, the sky was almost white. Does the number of stops used to create the LCC file affect the exposure? So would two stops slowing of shutter speed have resulted in a better exposure after application of the LCC file to photo?
The exact exposure level of thee LCC shouldn't affect exposure. You just want to avoid a noisy LCC, so exposure is usually something like +2 EV. That will make sure that also vignetting and light fall-off will be well exposed with little noise from under exposure.
Second question: Should I have removed the polarizer when I created the LCC shot? Since a polarizer will have its own impact on the light rays, I would assume that it is advisable not to remove the polarizer.
Hard to say, but I'd keep things the same as with the actual scene exposures, so with filter.
Third, question, what happens if the LCC file is underexposed?
Underexposure will lead to more noise, and thus a lower quality equalization. There are measures in place to avoid the negative impact of underexposure noise as much as possible, but it always helps to use better quality LCCs.