Share Pixels

This script copies the selected area of a document to exactly the same place in another document.

Thus, we can, for example, add an inscription to a 16-bit photo without converting it to 8-bit mode.

1. Duplicate the original 16-bit image (File > Duplicate) and convert the copy to 8-bit mode (Image > Mode > 8 Bits/Channel).

Now you have the original 16-bit document (on the screenshot - "DSC_3833.NEF") and its 8-bit copy ("DSC_3833 copy").

2. In the 8-bit document, create a text layer, apply to it some effect or a filter if needed.
3. Select the inscription with a selecting tool.
4. Run "Share Pixels" script and the text appears on the 16-bit image.

A video-tutorial on this topic is available here.