Using "Levels" and "Curves" tools for alpha channel

[Tronic2 webforumsuser@macromedia.com]

Well, the topic says it all. This is one of the three Photoshop flaws that made me evaluate other programs, and I haven't figured out how to do it in Fireworks.

The operation is very simple: just apply "levels" or "curves" to alpha channel, just like you could apply it to red channel, for instance. However, there's no option for this.

So, how to do it?

Or alternately, could somebody tell me which program has
-Good UI (like Fireworks!)
-Good PNG support (like Fireworks!)
-This feature.

[Richiebee]

I'm not 100% sure on this, but my way of thinking sees this as logical :-)
..It might be what you're looking for...
Using live effects, apply Brightness/Contrast, then Convert to Alpha... You
can then go back and edit brightness/contrast giving you the same effect as
applying curves or levels applied to the alpha channel.
If your graphic already has an alpha channel, then I think you might have to
convert it to a flat object without alpha transparency first.

Is that any good to you?

Rich


--
Richie Bee
[url]www.richiebee.ca[/url]
Team Macromedia Volunteer for Fireworks
[url]www.macromedia.com/go/team[/url]
Sharing Fireworks Resources
[url]www.richiebee.ca/public[/url]
-iii<O


"Tronic2" <webforumsuser@macromedia.com> wrote in message
news:bib81j$6a7$1@forums.macromedia.com...

> Well, the topic says it all. This is one of the three Photoshop flaws that

made me evaluate other programs, and I haven't figured out how to do it in
Fireworks.

>
> The operation is very simple: just apply "levels" or "curves" to alpha

channel, just like you could apply it to red channel, for instance. However,
there's no option for this.

>
> So, how to do it?
>
> Or alternately, could somebody tell me which program has
> -Good UI (like Fireworks!)
> -Good PNG support (like Fireworks!)
> -This feature.
>
>
>

[Tronic2 webforumsuser@macromedia.com]

I'm not 100% sure on this, but my way of thinking sees this as logical :-)
..It might be what you're looking for...
Using live effects, apply Brightness/Contrast, then Convert to Alpha... You
can then go back and edit brightness/contrast giving you the same effect as
applying curves or levels applied to the alpha channel.
If your graphic already has an alpha channel, then I think you might have to
convert it to a flat object without alpha transparency first.

Is that any good to you?


Unfortunately this doesn't seem like what I'm after. My image already has alpha, and I must keep the real alpha there (for later manipulations and finally PNG export).

[Lanny Chambers]

In article <bibidu$h3i$1@forums.macromedia.com>,
"Tronic2" [email]webforumsuser@macromedia.com[/email] wrote:

> Unfortunately this doesn't seem like what I'm after. My image already has
> alpha, and I must keep the real alpha there (for later manipulations and
> finally PNG export).

You can always duplicate the alpha, hide the original from export, then
play with the copy.

--
Lanny Chambers, St. Louis, USA
[url]http://www.hummingbirds.net/[/url]

[Tronic2 webforumsuser@macromedia.com]

I'm learning the program - I found out that it actually does allow using levels and curves for masks (which are same as alpha), but that my source image (PNG) only shows up as a "Bitmap" with no separately selectable mask. Any tips on how to separate the PNG alpha and color into Fireworks' color and mask (ie. how to get the PNG alpha layer editable)? Adding a mask to the bitmap gives a new alpha map that can be used for making the image more transparent, but making it less transparent is not possible with that.