Adjusting opacity/transparency in a selection?

[shunithD]

Hi...

Here's a poser from a friend...

1. Create a new layer

2. Fill with any colour - say red

3. Create a selection

4. Now, you can delete the selection, fill the selection with another colour, a couple of other things too...

The question:

How do you change the opacity/transparency within the selection?

Sure you can do it (get the effect) by using masks and additional layers, effects, etc... but is there a simple, direct way?

[Noel Carboni]

Normally one would use a layer mask.

But if you're constraining this that it MUST be done without using a layer mask, one way just offhand might be this:

1.  Make a copy of the layer you want partially deleted as a new layer over the original.

2.  Make a selection and delete the contents of the selection on the lower (original) layer.

3.  Set the opacity of the new upper layer to a percentage (e.g., 50%).

4.  Merge the partially transparent upper layer down into the layer that was partially deleted.

You could also use the Eraser tool with a brush set to partial Opacity, and you'd have to make sure you brushed over the whole area that's selected.

I can think of other ways one could do it using a partial selection derived from a grayscale channel.

I guess the question is:  Why not just use a layer mask and paint gray on it if you want partial transparency?

Keep in mind one thing:  Layer masks allow you to vary your transparency level at the full depth of your data, while you are always limited to 256 levels of transparency in the layer itself.

-Noel

[shunithD]

Hi Noel...

Thanks for the reply... yup, i know there are lots of ways... this guy (a very good friend) was ranting! (He's wont to do so!!) Anyway, he had what i thought - in a kind of left field way - was a valid point... if you make a select and can add colours to a selection, delete it, apply filters to it, etc., all without affecting the rest of the layer, then why can't you just reduce the opacity of the fill or the transparency of that selection? Tried to explain to him that some effects/attributes/etc. can only be applied to layers... anyway... to cut a long story short, i posted the query and i think your suggestion of the eraser with a reduced opacity seems to be the closest minimal effort solution to his rant!

Thanks again... hoping some other answers float in!

S

[Noel Carboni]

Sounds like he's looking for a "partial delete" then.  Maybe something controllable via a dialog that comes up if you do Edit - Clear with some combination of modifier keys held down.  I can see how such a thing could be useful occasionally.

Have your friend submit a feature request via the Adobe Bug/Wish form.  I'm sure they're always looking for nice little features to add that wouldn't be hard to implement and which would entice people to upgrade to the latest version.

-Noel

[shunithD]

Noel Carboni wrote:

Sounds like he's looking for a "partial delete" then.  Maybe something controllable via a dialog that comes up if you do Edit - Clear with some combination of modifier keys held down.  I can see how such a thing could be useful occasionally.

Have your friend submit a feature request via the Adobe Bug/Wish form.  I'm sure they're always looking for nice little features to add that wouldn't be hard to implement and which would entice people to upgrade to the latest version.

Naah... not worth it... because the other hassle is... it would be destructive... well, so is a fill or filter or... under the same circumstances... anyway, think your erase with brush settings works well under the circumstances...

But actually, just curious as to why a selection area cannot have it's opacity transparency changed?

[Guest · Accepted solution]

You could also make a selection and then go to Edit>Fill and choose Clear

for the blending mode, then go to Edit>Fade to adjust the opacity.

MTSTUNER

[Noel Carboni]

There you have it - it's already there.  I didn't realize "Clear" was in that list (thanks for teaching me something yet again, MTSTUNER).

And you don't even need to use Fade - the Fill box has a percentage selector.

Edit - Fill, Clear mode, set the amount of opacity.  Done.

-Noel

[Hominid Pinkage]

What do you do when "Clear" is disabled/grey?  It's the only option that is disabled.  At first I got an error message that the area was not directly editable, and then I tried merging the layers and then selecting a color range.   The selection step seemed to work fine, but then I found that after going to Edit>Fill>Blending Mode, the "Clear" option was disabled.

[PECourtejoie]

Hi, I wonder what is the color mode [Edit>Mode] of the image, is it RGB?

[Semaphoric]

I had TOTALLY forgotten about that! I was going to suggest partially filling a Quick Mask and then Clearing, but this is one step, as the OP wanted.

For you keyboardists, it's Shift + Backspace. It retains your last settings, so if you have a bunch to do, you only need to set the Mode to Clear the first time.

Now I have to go and refresh my memory on how "Behind" works . . .

[shunithD]

Noel, Mtstuner, Semaphoric...

Brilliant! As always, there's a way... if only you can find it!!! And as always, several ways to skin the cat

Thanks tonnes folks...

PS: Shift + F5 is another shortcut...

[PECourtejoie]

Hello! Here is another way, that is non destructive: create your selection, open the mask panel, click create a mask, invert it, and use the density slider to vary the opacity of your selection.

[shunithD]

PECourtejoie wrote:

Hello! Here is another way, that is non destructive: create your selection, open the mask panel, click create a mask, invert it, and use the density slider to vary the opacity of your selection.

Thanks for that one as well... the whole thing actually started when a friend of mine asked why we can't directly adjust the transparency of a selection in a layer... after all, we can fill it, delete it, apply a filter to it, etc.... so his thinking went... anyway...

Thanks again...

NB: The hassle with this is you can't, for instance, have a red layer with a selection where only the slected areais lightened... if you know what i mean... there are a couple of hoops to jump through

[PECourtejoie]

shunithD wrote:

there are a couple of hoops to jump through

If you need to perform a given task routinely, just record an action...

[Semaphoric]

Anothrert way (32-bit only): Install the Adobe Photoshop Filter Factory, and map the A value to one of the sliders.

[shunithD]

Semaphoric wrote:

Anothrert way (32-bit only): Install the Adobe Photoshop Filter Factory, and map the A value to one of the sliders.

Thanks for that suggestion... but self-defeating, if you refer to my original post

[Semaphoric]

shunithD wrote:

Thanks for that suggestion... but self-defeating, if you refer to my original post

Well, you only have to write it once. Save and compile it, and you have an .8bf filter you can then invoke via an Action with a hot key.

[shunithD]

Semaphoric wrote:

Well, you only have to write it once. Save and compile it, and you have an .8bf filter you can then invoke via an Action with a hot key.

Pierre, Semaphoric...

Just check out MTSTUNER's suggestion (with Semaphoric's) keyboard shortcut... it gives exactly what was required without having to jump through hoops...

Creating a mask will allow the area selected to be selectively 'faded' but masks out the rest... MTSTUNER's suggestion only 'fades' the selection, leaving the rest intact...

[PECourtejoie]

If you invert the mask, as I wrote in my instructions, you can leave everything intact and change the opacity of the selection...

But indeed, an action could come handy!

[shunithD]

PECourtejoie wrote:

If you invert the mask, as I wrote in my instructions, you can leave everything intact and change the opacity of the selection...

But indeed, an action could come handy!

But why? When MTSTUNER has already given a simpler way...

[PECourtejoie]

As I stated in my first post, using the masks panel is non destructive. I'm just giving an alternative method, that could withstand a move to 0% opacity, and yet retain the pixels...