How does one change the transparency of pixels?

I have what should be a basic Photoshop (CS) question.
If I have pixels which have some transparency to them (I am talking about pixels not a layer mask), how do I change that transparency without having to repaint the pixels?

If the transparency is part of the pixel–that is, not part of a layer mask–you can’t.

If you start working with layer masks–for example, filling a layer with color, then drawing in a layer mask to "erase" part of the layer–you won’t find yourself dealing with this problem.
—
Art, literature, shareware, polyamory, kink, and more:
http://www.xeromag.com/franklin.html

You can also try this.

Select the magic wand tool.

In the info bar beneath the menu bar there is a check box for antialiasing. Turn it off.

Now. click on the pained area. You may have to change the latitude to get the area you want. 0 will select only pixels that have same value. As you increase the number, the selection will grow.

Once you have made your selection, go to the menu and Select>Inverse

Now hit the delete key. What you end up with should be a ragged
i.e. non antialiased area.

dp

Tacit wrote:

I have what should be a basic Photoshop (CS) question.
If I have pixels which have some transparency to them (I am talking about pixels not a layer mask), how do I change that transparency without having to repaint the pixels?

If the transparency is part of the pixel–that is, not part of a layer mask–you can’t.

If you start working with layer masks–for example, filling a layer with color, then drawing in a layer mask to "erase" part of the layer–you won’t find yourself dealing with this problem.

On 20 Jul 2004 08:17:26 -0700, (WD) wrote:

Folks,

I have what should be a basic Photoshop (CS) question.
If I have pixels which have some transparency to them (I am talking about pixels not a layer mask), how do I change that transparency without having to repaint the pixels?

My question comes from having a situation where anti-aliasing has caused some pixles to become partially transparent (or less then 100% opacity). But I want to make them completely opaque again without the tedium and difficulty of repainting them.

Any ideas?

W

Threshold is not working for that?

Thanks all!!

I basically used dp’s suggestion. Also unchecked contiguous. I created a selection of the area then on a new layer filled it with a solid color.
I was luck in the fact that in this case all the pixes were of the same
color just with varying opacity/transparency.

I am surprised that Photoshop does not have a more direct way to deal with this, perhaps a ‘pixel transparency eraser’. Seems like this should just be a
fourth color value, e.g. R,G,B,T where T is transparency. Of course there could always be some obscure direct way to do it…after all
this is Photoshop. 🙂

W

"D.Plank" …

You can also try this.

Select the magic wand tool.

In the info bar beneath the menu bar there is a check box for antialiasing. Turn it off.

Now. click on the pained area. You may have to change the latitude to get the area you want. 0 will select only pixels that have same value. As you increase the number, the selection will grow.
Once you have made your selection, go to the menu and Select>Inverse
Now hit the delete key. What you end up with should be a ragged
i.e. non antialiased area.

dp

Tacit wrote:

I have what should be a basic Photoshop (CS) question.
If I have pixels which have some transparency to them (I am talking about pixels not a layer mask), how do I change that transparency without having to repaint the pixels?

If the transparency is part of the pixel–that is, not part of a layer mask–you can’t.

If you start working with layer masks–for example, filling a layer with color, then drawing in a layer mask to "erase" part of the layer–you won’t find yourself dealing with this problem.

On 20 Jul 2004 20:33:48 -0700, (WD) wrote:

Thanks all!!

I basically used dp’s suggestion. Also unchecked contiguous. I created a selection of the area then on a new layer filled it with a solid color.
I was luck in the fact that in this case all the pixes were of the same
color just with varying opacity/transparency.

I am surprised that Photoshop does not have a more direct way to deal with this, perhaps a ‘pixel transparency eraser’. Seems like this should just be a
fourth color value, e.g. R,G,B,T where T is transparency. Of course there could always be some obscure direct way to do it…after all
this is Photoshop. 🙂

W

Odd, I thought threshold would do what you wanted.

I tried threshold, it did not work. It seems to work in a mode that is unaware of a pixel’s transparency.

(ZONED!) wrote in message news:…

On 20 Jul 2004 20:33:48 -0700, (WD) wrote:

Thanks all!!

I basically used dp’s suggestion. Also unchecked contiguous. I created a selection of the area then on a new layer filled it with a solid color.
I was luck in the fact that in this case all the pixes were of the same
color just with varying opacity/transparency.

I am surprised that Photoshop does not have a more direct way to deal with this, perhaps a ‘pixel transparency eraser’. Seems like this should just be a
fourth color value, e.g. R,G,B,T where T is transparency. Of course there could always be some obscure direct way to do it…after all
this is Photoshop. 🙂

W

Odd, I thought threshold would do what you wanted.

WD wrote:

Folks,

I have what should be a basic Photoshop (CS) question.
If I have pixels which have some transparency to them (I am talking about pixels not a layer mask), how do I change that transparency without having to repaint the pixels?

My question comes from having a situation where anti-aliasing has caused some pixles to become partially transparent (or less then 100% opacity). But I want to make them completely opaque again without the tedium and difficulty of repainting them.

Any ideas?

W

Is it me or are you misusing the term transparency here ? An antialiased bit in a layer is just a set of pixels in a transition colour from one object to the next if I am correct. Has nothing to do with transparancy afaik. Nor with opacity, although with the opacity slider you can get the same end-result colour. Once you merge layers it has the same result, but as long as it’s on a separate layer the colour value of the pixel remains unchanged. when antialiasing the colours actually have changed.
Or am I lost in the woods now ?
Pjotr

"Pjotr Wedersteers" …

WD wrote:

Folks,

I have what should be a basic Photoshop (CS) question.
If I have pixels which have some transparency to them (I am talking about pixels not a layer mask), how do I change that transparency without having to repaint the pixels?

My question comes from having a situation where anti-aliasing has caused some pixles to become partially transparent (or less then 100% opacity). But I want to make them completely opaque again without the tedium and difficulty of repainting them.

Any ideas?

W

Is it me or are you misusing the term transparency here ? An antialiased bit in a layer is just a set of pixels in a transition colour from one object to the next if I am correct. Has nothing to do with transparancy afaik. Nor with opacity, although with the opacity slider you can get the same end-result colour. Once you merge layers it has the same result, but as long as it’s on a separate layer the colour value of the pixel remains unchanged. when antialiasing the colours actually have changed.
Or am I lost in the woods now ?
Pjotr

In this case the anti-aliasing is done via pixel transparency. Think of black
anti-aliased lettering. The ‘anti-alias transition’ pixels have some transparency to them. The letters are black. With a white underlying layer,
the transition pixels look grey. With a purple underlying layer, the transition
pixels look pink. With a black underlying layer everything (including transition pixels) looks black. So in this case the anti-aliasing is done via pixel transparency

W

(WD) wrote:

Folks,

I have what should be a basic Photoshop (CS) question.
If I have pixels which have some transparency to them (I am talking about pixels not a layer mask), how do I change that transparency without having to repaint the pixels?

My question comes from having a situation where anti-aliasing has caused some pixles to become partially transparent (or less then 100% opacity). But I want to make them completely opaque again without the tedium and difficulty of repainting them.

Any ideas?

Select the transparency of that layer with the magic wand, set to a tolerance of zero and "Contiguous" deselected. This selects all fully transparent pixels. Invert the selection, create a new layer below the actual layer, fill this layer with white. Use the selection as a layer mask, merge the top layer down. Now all partially transparent pixels are replaced by the equivalent solid color. By using a colored layer instead of a white one, or by changing the tolerance of the magic wand to higher values, you may get a result which better suits your needs.

Peter