In theory, could you have white balanced with the un-filtered strobes and achieved a similar effect? Does the compensation filter on strobe make the foreground white balance easier/better?
Thanks!
No, it is the strobe filter that is actually doing the work. The lens filter is actually optional; it's purpose is to achieve a better white balance before hitting the sensor. Without the lens filter you are wasting a stop (in this case) of your dynamic range to color correction but you can make that choice if you like. With the lens filter you will need to increase your exposure a stop, of course. With radical strobe filters a lens filter may be needed because the raw converter may not have the adjustment range.
The lens filter effects everything in the scene so it cannot make the background bluer without making the subject bluer as well. The strobe filter alters the foreground color without effecting the background so it is the filter actually having the effect. It is counter-intuitive and the filter needs to be opposite of the desired effect but that's how it works. Adding green to the strobe reduces green in the background, adding warmth to the strobe decreases warmth in the background, and so on...
Looks good, James. I'd like to see comparison shots as well.
I did a similar thing once (for different reasons) and was shooting with un-filtered strobe with a magic-filter on the lens ... I found I could get good foreground color if I white balanced live with the strobes firing.
This can be done but it accomplishes nothing other than to allow you to have a non-removable filter. The color balance of the strobe will always determine the white balance of the image. All the lens filter does is change the actual settings in the converter; it does not effect the final image. This behavior is unique to digital. Film has a fixed white balance so filter usage is different between digital and film.