Topic awaiting preservation: Opacity values of pixels? How to disable anti-aliasing?

Hi,

I would like to know how to do the following fast. For example if you draw a circle in Photoshop, Photoshop automatically processes the figure's borders and lowers the opacity values of the border pixel to create a smoother edge. I would need to transform all these half-transparent pixels to fully opaque pixels, preserving their current color tones.

Is this possible? How?

(my interface doesnt support alpha channels, I have to use a transparency color)

(Edited by Arnitald on 03-02-2005 19:58)

Grab the opacity by Ctrl+click on the thumb of the layer, create a mask layer, then use the Levels on the Mask to show everything with an opacity above 50%, or above 0%. Try to find a value that provide the best result and suits your technical requirements.

You should also have a look at :

1. How do I make a transparent graphic?
2. Hands On : Transparency
3. Hands On : Transparency 2

Hope that helps,

personally, I often end up just duplicating my layer till all something% pixels are 100% ;-)

This is a sorely needed feature in Photoshop. It's strange that it gives so much control in terms of working with individual channels and separating red, green, and blue, but then doesn't let you simply work with the alpha channel like any other.

Poi's method works when all you're dealing with is a solid color, but when you have a more complex layer with various colors and partial transparency and anti-aliasing, although you can still get the alpha channel in the normal way you can't change it and then reapply it to the existing layer.

Sadly, TP's method is the only one that really works all the time, and it's slow.


 

I used to have an action that did ( copy + merge down ) x 4.
Then I did Opacity Pump for exactly this.
If you bother with Filter Factory, just use A=255 and let it fly.

Actually, to get better results and keep control of the number of colors with some transparent GIF I've sometime worked on the blending areas ( read, partial transparency and even some parts of the AA ) and solid areas separately. That is I made a clean GIF for the blending areas, then made one with just the solid areas, and finally combined them together.

Tyberius Prime: Ctrl+J and Ctrl+E are my friends too

WJ: filter factory?


 

[Edit: nevermind... Misread]



(Edited by synax on 03-03-2005 01:11)

Filter Factory used to ship with PS in Goodies or something.
I couldn't tell you if it still ships or not.
Fire it up, put in your code, and make it go.

http://thepluginsite.com/knowhow/ffpg/ffpg.htm

I also use TP's brute force method(which doesnt really take long at all to do, duplicate a load of times then merge em all), another way is to use the magic wand on the surroundings , invert the selection and create a block of white behind the orignal layer, or just ctrl+shift+c the inverted selection. But this requires a good bit of tweaking with the magic wands settings as usual.

Dont mean to hijack; But does anyone know how to turn off anti-aliasing with free-transform, or set it to use "nearest neighbour" when its resizing.

Hugh:

quote:

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Dont mean to hijack; But does anyone know how to turn off anti-aliasing with free-transform, or set it to use "nearest neighbour" when its resizing.

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Temporary set the interpolation ( via Ctrl+K, Alt+t ) to the method of your choice just before you free-transform your selection, then you can reset it.

So there is no way to manipulate the alpha channel of a layer?

Damn, that is like in the stone age . Ok thanks for the tips... I will merge the image into one layer and use the overlay method... i knew about that but I thought there was some other way.

Thanks for helping!

I'm not sure what you mean by "manipulate the alpha channel of a layer", but if you are talking about a mask that you would make from a selection, you can manipulate it by using Quick Mask Edit (one of the two small buttons at the bottom of the Tool Palette) or you can click on the channel for the alpha channel in the Channels Palette and manipulate the alpha channel that way.

If you're speaking of a layer mask, you can manipulate that channel by high-lighting the layer in the Layers Palette, then clicking on the mask icon next to the content icon.



.

-- not necessarily stoned... just beautiful.


(Edited by hyperbole on 03-03-2005 21:26)

Arnitald: If you press Alt and click on the thumbnail of a Mask Layer, you'll see it in B&W and will be able to draw on it, apply some filters, copy/paste, etc... which gives a rather high level of control of the opacity.