Sandman
In article <dlip1atj87lout9dl7fl5eje2uaddfdril@4ax.com>, Eric Stevens wrote:

nospam
which means the changes are reversible.

Eric Stevens
You are not reversing the changes: you are substituting for them.

Sandman
Removing an effect reverses it 100%. No substitution involved. You are confused.

Eric Stevens
When I (and Floyd) say 'fully reversible' we are using a very specific meaning.

Sandman
You may pretend to be the spokesperson for Floyd all you want, Eric, and you may also insist on not noving what the term means as well - but image processing in Lightrom is 100% reversible at all times. This doesn't change just because you guys don't know any better.

Eric Stevens
For example, saving an image as a JPG is not fully reversible in that you cannot reconstruct the exact original image from the JPG. There will be differences which can be corrected only if you bring in additional (pixel) information from outside the reconstructed image.

Image 1 --->JPG --->Image 2 is not a fully reversible process. Image 1 cannot = Image 2.

Sandman
Yes, we know Floyd was incorrect when he claimed that JPG compression was reversible.

nospam
not only do i realize it but that's what i've been saying all along.

you are *so* confused.

Eric Stevens
And I have pointed out that you cannot reverse a change which has not actually been made. Even if it is reversible, you can't reverse something before you have done it.

Sandman
No one has talked about reversing things you haven't done. We've been discussing Lightroom, where you can reverse everything you have done.

Eric Stevens
I don't want to continue to wander down yet another of nospam's side paths, but I was pointing out that changing an edit before a file is exported isn't actually changing anything in the final exported image, so you can't claim to have reversed anything in the image.

Sandman
Which would only be a problem if that was the only copy of the image. Since it isn't, the end result is fully reversible. This is how modern photography works.

You just haven't kept up with all this new-fangled technology thingies.