converting 16 bits to 8 in PE7

[mapgirl]

Whenever I move an image from Lightroom 2 into Photoshop Elements 7 for further editing, I get a prompt telling me that in order to use some of the tools there I have to convert from a 16 bit color depth to 8 bit. What does that do to my finished image after moving it back to Lightroom? Can/should I do something to retain the 16 bit image in PE7?
Thanks!

[kcoppock]

Yeah, some of the tools are not written to work in 16-bit mode. I would recommend keeping it in 16-bit mode as long as possible, unless there just happens to be an incompatible tool you really need to use on it. The short answer on what happens when you convert is that the tones get compressed from having 65,536 possible values to only 256. When editing, it's best to work in 16-bit if at all possible.

[mapgirl]

Originally Posted by kcoppock

Yeah, some of the tools are not written to work in 16-bit mode. I would recommend keeping it in 16-bit mode as long as possible, unless there just happens to be an incompatible tool you really need to use on it. The short answer on what happens when you convert is that the tones get compressed from having 65,536 possible values to only 256. When editing, it's best to work in 16-bit if at all possible.

Thanks Kevin. Would a more recent version of PE solve the problem?

[kcoppock]

Originally Posted by mapgirl

Thanks Kevin. Would a more recent version of PE solve the problem?

It's possible it may add a few things, but really, no. I have CS5, and there are a lot of tools that aren't 16-bit compatible. The Artistic, Brush Strokes, Distort, Pixelate, Sketch, and Texture categories of filters in their entirety are incompatible, as well as things like Render > Lighting Effects. Those were all written around working on 8-bit images, and they all have to be completely rewritten to work on 16-bit images, so I imagine they just take a lower priority to new features. To me, there aren't any features I miss when I'm working in 16-bit mode; at least, none that I can think of. I would just accept the warning, stay in 16-bit, and see if you end up with any problems. Worst case, you can convert back to 8-bit at any time with Image > Mode > 8-bit.

[mapgirl]

Please forgive me if I'm a little slow with this. So if I have to convert to 8 bit for certain tools, what happens when I move the image back to Lightroom 2? Does it automatically convert back to 16? If not, what can I do to convert it? And what has been lost or compromised in the process?

Thanks so much for helping!

[kcoppock]

No problem. It's not a simple concept. Once you've converted to 16-bit, the additional data is lost permanently, so it's best to save that for last. It's incredibly unlikely, if not impossible, that you'll notice a difference visually upon conversion, but further edits will lose quality. Admittedly, outside of major edits, you'll probably not see an appreciable difference, depending on your output (a good print will be more likely to show a difference, whereas on screen you won't notice). I'm a bit obsessive about stuff like that though, and I figure it never hurts to work from the best quality original possible.