P: Updating process in LR4 unexpectedly zeroes out exposure brush value.

I was able to reproduce this fully.

1. Rename preferences, reboot Windows 7, start LR, create a fresh catalog.

2. Import two new files (Canon EOS 1d) as DNG.

3. Go into develop mode on first file. Set PV to 2010. Paint a big blob in the centre and set all brush settings to maximum.

4. Go into Grid mode. Sync Settings from second image to first, selecting only process version.

Voila: The big blob on the first image disappears (only saturation and sharpness remain unchanged).

Just tested as you described and I am not seeing it.

When I use sync, I get precisely the same results as I do when hitting the exclamation point.

Everything remains in place except the new tools Highlights, Shadows, Noise, Moire, and Defringe which are all zero.

You may want to reboot or rename your Prefs file and see if the behavior persists.

BUG.

I've looked at this some more and I do believe it is a bug. In fact the zeroing out only happens when PV is applied using Sync Settings (with only PV selected).

To replicate this I applied a brush on a PC 2010 image with all attributes set to maximum. Clicking on the exclamation mark to convert to PV2012 produced the desired result. However using Sync Settings instead, caused Exposure, Contrast, Clarity all to be set to zero. Saturation and Sharpness were correctly left alone in the conversion.

[Rikk:] In answer to your comments, yes of course many people don't need to update PV2010 images. However mine are constrasty Leica shots and they benefit significantly from PV2012's better handling of shadow areas, so as I reuse my images I am updating most of them. I am expecting to make adjustments to all of them, but not to have to fix things that LR has unexpectedly zeroed out. In general a slightly bump on clarity and sometimes shadow levels is required, but I should not have to open up every brush and put back my settings.

It may be because you have used "Brightness" in your PV2010 Adjustment Brush. PV2012 does not have a Brightness control. Brightness and Exposure are now a single slider called Exposure with slightly different behavior. You will need to decide which combination of Exposure, Highlights or Shadows does the best job and adjust each accordingly.

This problem doesn't happen to too many people because it is accepted wisdom that you don't upgrade an image PV unless you need to, The lack of a direct conversion between the two adjustment sets makes it problematic.

If your image is finished, don't update. If you do update, realize that local adjustments may have to be tweeked individually.