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I have image which as black background and i want to remove the black background and use the image as transparent only color smoke.

enter image description here

Image

atek
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    Does the base image have transparency? – lemon Sep 17 '19 at 15:34
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    @brockmann i want to remove the black background to make it transparent – atek Sep 17 '19 at 15:34
  • @lemon i have attach the image above in questions its totally black without transparency . I want to remove it like photoshop we use screen option to remove black background. – atek Sep 17 '19 at 15:37
  • you could use a b&w version of your image that you'd plug into a ColorRamp that you'd plug into a factor of a Mix shader that mixes the color version and a Transparent node, but you'll always have a grey zone – moonboots Sep 17 '19 at 15:37
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    Just match the Image Texture's color shocket to the Mix Shader's Fac shocket instead of the Alpha. You can put a ColorRamp between them if you want to adjust it but it's not necessary. – FFeller Sep 17 '19 at 15:45
  • I think the best result may be to process the image before using it in Blender. With Gimp for instance "color to alpha". – lemon Sep 17 '19 at 15:49
  • @FFeller i tried as suggested plug the image texture to mix shader face the transparency created bu the color disappeared. – atek Sep 17 '19 at 16:02
  • https://imgur.com/a/vKpd40J, if that can help (done using Gimp>Layer>Transparency>Color to alpha) – lemon Sep 17 '19 at 16:08
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    Did you plug it also in the diffuse shader? – FFeller Sep 17 '19 at 16:13
  • @FFeller perfect thanks. Can you plz drop the node as answer many be for others it can be helpful – atek Sep 17 '19 at 16:23
  • Read this answer: Glow effect invisible on transparent background – susu Jan 26 '21 at 18:53

2 Answers2

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You don't necessarily use the Mix Shader with the alpha channel of the image. You can also use the color channel. So on the darker areas the first shader (Transparent) will dominate and on the lighter parts the second shader (Diffuse) will get a higher value. You can plug a ColorRamp before the Fac shocket to finetune the silhouette. Of course you can use images with white background, just swap the transparent and diffuse shaders. enter image description here

FFeller
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enter image description here

For anyone that comes back, here's a simpler node setup. Just run the image texture's color output through a principled shader's alpha attribute. That's the quick and dirty way, but an added color ramp in between gets a much nicer result. With a bit of tweaking, this should allow you to make most images transparent.

Cullen Sharp
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