Eric Stevens
On Thu, 18 Sep 2014 22:55:27 -0400, nospam <nospam@nospam.invalid> wrote:

nospam
In article <ld4n1a1cmj32ak5ua8fl5s515112u8ljh7@4ax.com>, Eric Stevens <eric.stevens@sum.co.nz>wrote:

Eric Stevens
As nospam has so often told us, Lightroom (and other software using side car files) do not actually change the file being edited until it is in the process of being exported. In most case, all you see on the screen is a simplified simulacrum of what the edited file will look like, when the editing instructions are executed.

Once you export the file - that's it. You cannot reverse the changes. All you can do is edit the original all over again but this time slightly differently.

nospam
which means the changes are reversible.

Eric Stevens
You are not reversing the changes: you are substituting for them. Surely even you can see that?

nospam
you're overanalyzing things again.

the user makes a change to an image and quits the app. the next day

Eric Stevens
All they have done up to this point is create a list of edits and view a simulacrum of their effect in screen. They haven't actually edited the image.

nospam
they resume working on the image and decide to reverse what they did the day before.

Eric Stevens
So they change the list of edits and againview the changed simulacrum which results. They haven't actually created any image to be changed at either point. That oonly happens once they execute the list of edits by exporting the image.

nospam
with a non-destructive workflow, they can do that. without a non-destructive workflow, the changes cannot be reversed.

Eric Stevens
Once they have executed the list of edits by exporting a file the changes can't generally be reversed either.

nospam
the key here is the workflow.

Eric Stevens
Now it's interesting that Lightroom does incorporate something a little bit like the reversible process that Floyd was talking about but neither nospam or Savageduck seem to realise the fact. See http://tinyurl.com/p5sus42 From blur to sharpness on the one slider. But this is not actually a reversible process: it's a change in the instruction to the final edit which will only be executed when the image is exported.

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.

nospam
the change *has* been made, just not to the pixels themselves.

Eric Stevens
And to what has the change been made?

nospam
as i said, you're confused.

Eric Stevens
I'm confused?