When exporting to NIK or any other plug, Lightroom asks for some information.
AFAIK, and the more I study the less I know, the exported file should be a TIFF (no good options there), ProPhoto RGB (I've read that sRGB restricts the color space), 16 bits/component, and the resolution leaves me puzzled.
The file sizes seem to be the same. There should not be a downsizing involved. So ... is that just "a number" or will it have any effect at all later on?
The idea is that you don't want to be applying compression to the image that will result in reduced quality. Tiff is a lossless image format and so it will preserve the raster data perfectly fine. I'm unsure about ProPhoto RGB as I've never worked with it. The one thing that is worth noting is that you will need to make sure your adjustments to your RAW file are finished before the export. Exporting will result in working with RGB image data rather than original sensor data, so you will lose some of the flexibility when it comes back, though you can maintain the high bit-depth to keep a lot of the ability to adjust exposure.
