Savageduck
On 2014-09-15 22:33:57 +0000, Eric Stevens <eric.stevens@sum.co.nz>said:

Eric Stevens
On Mon, 15 Sep 2014 10:15:37 -0700, Savageduck <savageduck1@{REMOVESPAM}me.com>wrote:

Savageduck
On 2014-09-15 16:39:45 +0000, floyd@apaflo.com (Floyd L. Davidson) said:

Floyd L. Davidson
nospam <nospam@nospam.invalid>wrote:

nospam
In article <87bnqh1mby.fld@barrow.com>, Floyd L. Davidson <floyd@apaflo.com>wrote:

Floyd L. Davidson
UnSharpMask is not reversible.

nospam
it is with a non-destructive workflow.

Floyd L. Davidson
I'm sorry that you don't understand the meaning of that.

Savageduck
I know your feelings regarding Photoshop, but using Adobe's *Smart Object* concept provides a different level of non-destructive workflow. Creating a new adjustment layer and converting it to a *Smart Object* gives one the ability to apply any filter, including USM and any of the other sharpening tools or filters to that *Smart Object*. If the particular adjustment results are not to one's liking, then double clicking on that filter in the *Smart Object* layer will reopen the filter dialog to allow changes to the filter parameters. In the case shown below I have applied USM to a *Smart Object* and I can return to it as often as I want to adjust the USM parameters, all non-destructively. <https://dl.dropbox.com/u/1295663/FileChute/screenshot_900.jpg>

All adjustments made to *Smart Objects*, in Photoshop terms, are non-destructive.

I fully expect you to tell me I am wrong.

Eric Stevens
I will tell you that you are discussing a point which is not the point raised by Floyd. So too is nospam, but that is not surprising.

Floyd was referring to a reversible function: run it forwards and you get sharpening; run it backwards and you get blur. Or the other way around if you wish.

Savageduck
I got what Floyd was talking about when he was talking of high pass sharpening, and reversing it by applying the corresponding reverse parameter blur. However, he also stated above, "UnSharpMask is not reversible". My point addressed the fact that for some of us, that is not an entirely valid statement.

…and if you have been following any of the PS books and tutorials, you can get confirmation of what I wrote there with regard to *Smart Objects* & resulting *Smart Filters*.