Today’s Question: When Lightroom and Camera Raw update their process versions, as they have recently, do you go back to any of your existing images and re-edit them with the new process version?
Tim’s Quick Answer: No, as a general rule I do not go back and change the process version for photos I had adjusted using an older process version, unless I want to revisit the adjustments I previously applied.
More Detail: The main reason to update the process version for an “older” photo would be to take advantage of any new features available with the updated process version. Sometimes that may be compelling, of course, depending on the new features added as part of an updated process version. For example, the Dehaze adjustment is only available with process version 2012 (version 3) or later.
When you change the process version for an image, there is a risk that the image will change in appearance based on differences between the process versions. Generally this doesn’t represent a significant issue, but it is reason enough (I think) to not simply batch update images to a new process version, and to instead only update when you’re revisiting the adjustments for an older photo.
After you’ve installed a Lightroom update that includes a new process version, any images you import into your catalog will automatically be updated to reflect the new process version. In other words, you only need to consider updating the process version for images that were already in your Lightroom catalog before a new process version was released. More to the point, this is primarily an issue for images you had actually applied adjustments to using an earlier process version.
You can change the process version for a photo using the Process popup in the Camera Calibration section of the right panel in the Develop module. In addition, an image that has the process version set to an older version will show a lightning bolt symbol in the Histogram section of the right panel in the Develop module. You can click that lightning bolt symbol to bring up a dialog with options for updating to the latest process version for the current image or for all images currently shown on the filmstrip.