Transparency questions — advanced

Hi,

I’ve been working with Photoshop for a long time, and there are three things with transparency I’ve never been able to figure out how to do. Maybe somebody can help me?

"crazyhorse" wrote in message

Hi,

I’ve been working with Photoshop for a long time, and there are three things with transparency I’ve never been able to figure out how to do. Maybe somebody can help me?

I admit I don’t understand the way you use the word Transparent, but I suspect you want to look into LAYER MODES. That’s the little box at the top of the layers palette. Try setting a layer to COLOR mode. I have to leave the lab now and haven’t a moment left to help, but I hope that nudges you in the right direction.

Better yet, I hope someone else comes in with the explicit directions. If we are lucky, the Curvemeister will look in on us.

I think Michael may have a different definition of transparency than the rest of us…

subdude wrote:

I think Michael may have a different definition of transparency than the rest of us…

Yup. That’s what’s happening.

Hi,

I’ve been working with Photoshop for a long time, and there are three things with transparency I’ve never been able to figure out how to do. Maybe somebody can help me?

The first is: how to make all the pixels in a semi-transparent layer 100% opaque, while preserving their colors. This is different from simply pasting onto a white background, because in that case a 10% opaque red would turn into a light pink, whereas I want it to be 100% red. I suppose that 0% opaque pixels could be come white or black… (Theoretically you could do this by pasting the semi-transparent layer successively 255 times, but this is too much work…)

The second is: how to paste a first image onto a second, but preserving the transparency of the second? In other words, much like "painting with transparency" using the slash key, but copying-and- pasting instead. (Or, alternatively, copying-and-pasting just the transparency values from one layer to another, while preserving the colors).

The third is how to apply "curves" to transparency. For example, suppose I have a gradient that fades from black (0% opaque) to black (100% opaque). Let’s say I want to move the midpoint of that transparency so that it is closer to one end or the other–in effect adjusting the transparency of the semi-transparent parts, but keeping the 0% and 100% transparency sections the same.

Ideally this would be done by converting the transparency values to a black-to-white image, adjusting the curves, and then converting that back into the transparency values… yet I don’t see any way to do this in photoshop.

Can anybody help?

Thanks
Michael

The first is: how to make all the pixels in a semi-transparent layer 100% opaque, while preserving their colors. This is different from simply pasting onto a white background, because in that case a 10% opaque red would turn into a light pink, whereas I want it to be 100% red. I suppose that 0% opaque pixels could be come white or black… (Theoretically you could do this by pasting the semi-transparent layer successively 255 times, but this is too much work…)

The second is: how to paste a first image onto a second, but preserving the transparency of the second? In other words, much like "painting with transparency" using the slash key, but copying-and- pasting instead. (Or, alternatively, copying-and-pasting just the transparency values from one layer to another, while preserving the colors).

The third is how to apply "curves" to transparency. For example, suppose I have a gradient that fades from black (0% opaque) to black (100% opaque). Let’s say I want to move the midpoint of that transparency so that it is closer to one end or the other–in effect adjusting the transparency of the semi-transparent parts, but keeping the 0% and 100% transparency sections the same.

Ideally this would be done by converting the transparency values to a black-to-white image, adjusting the curves, and then converting that back into the transparency values… yet I don’t see any way to do this in photoshop.

Can anybody help?

On Aug 14, 9:23 pm, pico <pico.net> wrote:

subdude wrote:

I think Michael may have a different definition of transparency than the rest of us…

Yup. That’s what’s happening.

No… maybe my wording wasn’t clear enough. I want to take a layer that includes transparency information, and MAKE it 100% opaque (i.e. remove the transparency information) WITHOUT changing color values — not adding white or black or anything. And choosing some color (say, gray) ONLY for pixels that are at 0% opacity.

And then the other part of the question essentially involves turning the original per-pixel opacity values into an alpha layer, or mask, but I’ve just now figured out that you can do that by Ctrl+clicking on the layer in the layers palette, and edit the mask directly by Ctrl +clicking on it…

The end result here would be to separate out the color+opacity pixel information (which Photoshop stores together) into a totally opaque layer, with a layer mask that turned parts transparent again. This would facilitate my editing. But *without* creating a white or black halo around the antialiased/semi-transparent bits, which is what happens if you simply put the semi-transparent layer on top of a white or black background.

(so that a pixel with opacity of 1/256 bits would finally become

totally opaque), is there any easier way to do this?

Hope this is clearer now…

In article ,
crazyhorse wrote:

The first is: how to make all the pixels in a semi-transparent layer 100% opaque, while preserving their colors. This is different from simply pasting onto a white background, because in that case a 10% opaque red would turn into a light pink, whereas I want it to be 100% red. I suppose that 0% opaque pixels could be come white or black… (Theoretically you could do this by pasting the semi-transparent layer successively 255 times, but this is too much work…)

The second is: how to paste a first image onto a second, but preserving the transparency of the second? In other words, much like "painting with transparency" using the slash key, but copying-and- pasting instead. (Or, alternatively, copying-and-pasting just the transparency values from one layer to another, while preserving the colors).

The third is how to apply "curves" to transparency. For example, suppose I have a gradient that fades from black (0% opaque) to black (100% opaque). Let’s say I want to move the midpoint of that transparency so that it is closer to one end or the other–in effect adjusting the transparency of the semi-transparent parts, but keeping the 0% and 100% transparency sections the same.

Ideally this would be done by converting the transparency values to a black-to-white image, adjusting the curves, and then converting that back into the transparency values… yet I don’t see any way to do this in photoshop.

Can anybody help?

The answer to all of your questions is the same: Layer mask.
To answer the first question: Once you have made a pixel semi-transparent by doing something like using the Eraser tool, or by painting in a layer with the paintbrush set to be transparent, you can not later affect just that pixel’s transparency any more. So, never erase anything in a layer with the eraser tool or make some part of a layer transparent by using a painting tool set to transparent. Instead, make things on the layer transparent using a layer mask.
To answer the second question: If you have a layer that is transparent, you do not need to use copy/paste to get it into a second document. in fact, you should never use copy/paste to move anything from one Photoshop document to another. instead, just use the move tool to drag it from one document window into the second document window. Copy/paste uses extra memory to hold the contents of the clipboard, and is therefore less efficient than just dragging stuff from one window to another. If the thing you drag from one Photoshop image to another has a layer mask, the layer mask will go along with it too, and it will be transparent in the second Photoshop document.

The third is easy. Apply your Curves command to the layer mask.
A layer mask is black-and-white values that control transparency. That’s ow it works.