Sandman
Which is irrelevant, since no one in this thread has talked about a reversible process as used in physics.

Eric Stevens
Floyd was

and I understood what he was saying.

Unfortunately there are aspects of optics and image formation which cannot be accurately described in general terms. Floyd was being quite specific.

In using those words in that way he was expressing a particular rigorously defined meaning for which there is no substitute.

Sandman
Yes, we know you want to make Floyd appear to be an even bigger moron than he is, but he needs no help.

He was in reference to one process being reversible by the algorithm of another process, which would be a reason to use it instead of a process that can't be reversed by another algorithm. That's what he said and that's what he meant. It has nothing to do with physics or thermodynamics, that's you talking out of your ass. It has everything to do with mathematics.

Eric Stevens
Even now you haven't got it quite right. It's not the algorithm of another process: it's the same algorithm.

Sandman
And it's also born out of ignorance, because such a consideration is only important if you're using ancient tools, which Floyd is. For him, he HAS to take such things into consideration because his tools are so primitive that if he makes a change he can't revert it unless it has a counter-algorithm.

Eric Stevens
Even with the most ancient of tools you can achieve the 'undo' or reversion effect you are talking about simply by doing your editing on a copy of the original. I was doing this with Photo Paint macros, backin the early 90's.

Sandman
Modern photographers need not take such things into consideration, where using pretty much any tool made in the last decade makes *any* action fully reversible at any point in time.

That's the ignorance we're making fun of here.

Eric Stevens
Then you too are ignorant.

Sandman
Floyd tried to project the shortocmings of his own limited workflow to that of the OP, and gave misdirected "advice" based on what he himself can not do. The OP, of course, wouldn't be limited by Floyds ancient tools and need not that advice.

A proper analogy would be if a poster would ask advice on how to change the color of his car, and Floyd being a grumpy old man that knows nothing about modern technique says that he should paint it with a bursh, but remember that the process isn't reversible. More knowledgable people would chime in and say that changing the color of a car is a fully reversible process these days, with many different techniques depending on your needs.

Floyd, and Eric, would then say "noooo, you can't scrape off the color! it would ruin the car!" and we would hjave to spend some 50+ posts telling you about all the new techniques one could use that ARE fully reversible and you would both deny them until your last breath.

Eric Stevens
You could always use a water souble paint which will wash off with water.

Or you could use an acrylic paint which can easily be removed with a heat gun.

Or maybe you could use a vinyl stick-on film. But none of them would be a proper automotive paint.