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I am creating blank images within blender to add some fine detail, such as nails in wood boards. My blank image is black.

When I export the image and/or when I input it into image texture node in cycles, I cannot control the alpha channel, as it hasn't been saved.
When generating a new image, I am using all the default settings (including the option to create an alpha channel). Any suggestions on how to generate an image with usable alpha channel?

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  • $\begingroup$ I tried it (creating a black blank image) with the default settings, but it created a very usable alpha channel. In what way is the alpha channel not being usable? $\endgroup$ – gandalf3 Jul 13 '13 at 19:25
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I'm not sure I understand the question entirely..

If you want an image with a transparent background, Make sure you set the image background to completely transparent (assuming that is what you want)
enter image description here

When you save the image you also want to make sure you use an image format that supports alpha channels - png would be the most common.

The RGBA button enables saving the alpha channel and is only visible if the image format supports alpha.

(If you want to render the image, the RGBA button is in the render settings panel.).
enter image description here

You can then set up a simple material such as this:

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  • $\begingroup$ thanks. i did not realize that i need to set the color alpha value, since i thought that black is transparent and white is opaque, but i guess an image is not an opacitiy mask without somehow making it so :) $\endgroup$ – dimitarsp Jul 14 '13 at 18:57
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In blender 2.75a, you must also select your Image Texture node, in the Nodes view, because you must click a "Use Alpha" checkbox that you won't find anywhere else.

You'll find that checkbox only if the Image Texture node is selected in Nodes view. Reveal the view's built-in Properties pane, if it's not already visible on the right side of the Nodes view, by pressing the N key. (Pressing N repeatedly will show/hide the Properties pane).

On that pane, you'll see a "Use Alpha" box, but only if the Image Texture input node is selected.

BTW, that's also the only place I know of in the entire blender program where you can find a reload button to reload your texture, if it changed on disk.

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  • $\begingroup$ If you enable the Node Wrangler Add-on it, too, has a Reload Images button. Good stuff! $\endgroup$ – tobinjim Mar 17 '16 at 5:55

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