user3270: I have a video of smoke shot against a black background. I would like to make the background transparent so the smoke shows over the video in the background. 
I originally tried Remove Matte but that didn't seem to have any effect on the smoke video. I then tried Color Key and I was left with what you see below. (Original smoke is on left, the "keyed" version is on the right.)

I am using Adobe Premier Pro CC (v7.2.1). What is the best way to cleanly remove the black background while leaving the smoke. The goal is to have the smoke over the background video. 
I am a novice at this so please use clear instructions. If an option is buried in a menu, please tell me which menu. What I have tried has come directly from the Premier's Effects Panel.

user5660: The simplest way would be to set the blending mode of the smoke clip to "screen". You'll find this setting in the "Effect Controls" panel under Opacity. 
Screen basically ignores black. A better description is found on Adobe's site: http://helpx.adobe.com/en/photoshop/using/blending-modes.html

user5821: First off, you would normally use After Effects for special effects such as Chroma Keying. That being said, Premiere Pro is capable of chroma keying quite decently. Here's an example using free smoke effects by JohnnyFXEffects.
Set up your scene as you usually would, and then go to the 'Effects' tab. (1) From the 'Keying' folder, select the 'Chroma Key' option. (2) Simply drag and drop it onto your smoke video file. (3)

Next, select your smoke clip by clicking it, and go to the 'Effect Controls' tab in the upper left workspace. (1)  Expand 'Chroma Key' (2) and click the eyedropper icon in the same column as "Color". (3) Next, select the color you want to chroma key away by clicking in an area of your video with that color. (4)

Keep fiddling with your Chroma Keying settings untill you get the desired result. I found that setting similarity to around 7,5% (1) and Cutoff to around 50,0% (2) gave me a decent result.

Optionally add a few more video effects untill you get the desired result.

user2836: While chroma-keying is a good technique for dealing with solids, it doesn't work so well when dealing with transparent or semi-transparent objects.  Because the difference can be very subtle, you want to copy the difference instead or blend off luminance.
In Premiere, you can use the Set Matte effect to set a track as a luminance matte.  In the case of the sample of smoke from mmphilips post, the luminance was a bit low so I put it in a separate sequence and used curves to boost the overall luminance.  I then placed the matte on Video 3 and made it invisible.  I then placed the Set Matte effect on Video 2, pointed it at Video 3 and specified that it should use Video 3 as the matte.

The same thing can be accomplished in After Effects in a similar manner.  Again two copies are placed on the composition and the top most is made invisible.  The modes option toggles is clicked to bring up the proper controls and luminance is chosen for the second layer so that the third layer is used as a matte.  As shown, I applied curves to the third layer directly to make it blend more naturally.  Note that in this screen shot I actually inverted the matte layer and thus used inverted luminance, but those steps aren't necessary, I just made an error while getting it working and didn't bother to correct it.

Note how this results in much smoother results than a luminance key or chroma key since a luma or chroma key makes a hard cut off and is not able to do alpha blending based on the intensity of the smoke.  Smoke however is somewhat transparent and you want to be able to see through it where it is darker.  That's why this blending technique works.

3270: <p>I have a video of smoke shot against a black background. I would like to make the background transparent so the smoke shows over the video in the background. </p>

<p>I originally tried <code>Remove Matte</code> but that didn't seem to have any effect on the smoke video. I then tried <code>Color Key</code> and I was left with what you see below. (Original smoke is on left, the "keyed" version is on the right.)</p>

<p><img src="https://i.stack.imgur.com/9ORBX.jpg" alt="Screenshot of Smoke"></p>

<p>I am using Adobe Premier Pro CC (v7.2.1). What is the best way to cleanly remove the black background while leaving the smoke. The goal is to have the smoke over the background video. </p>

<p>I am a novice at this so please use clear instructions. If an option is buried in a menu, please tell me which menu. What I have tried has come directly from the Premier's Effects Panel.</p>
 5660: <p>The simplest way would be to set the blending mode of the smoke clip to "screen". You'll find this setting in the "Effect Controls" panel under Opacity. <br>
Screen basically ignores black. A better description is found on Adobe's site: <a href="http://helpx.adobe.com/en/photoshop/using/blending-modes.html" rel="nofollow">http://helpx.adobe.com/en/photoshop/using/blending-modes.html</a></p>
 5821: <p>First off, you would normally use After Effects for special effects such as Chroma Keying. That being said, Premiere Pro is capable of chroma keying quite decently. Here's an example using <a href="https://www.youtube.com/watch?v=o3YC2h8RGI4" rel="nofollow noreferrer">free smoke effects by JohnnyFXEffects</a>.</p>

<p>Set up your scene as you usually would, and then go to the 'Effects' tab. (1) From the 'Keying' folder, select the 'Chroma Key' option. (2) Simply drag and drop it onto your smoke video file. (3)</p>

<p><img src="https://i.stack.imgur.com/QczeN.png" alt=""></p>

<p>Next, select your smoke clip by clicking it, and go to the 'Effect Controls' tab in the upper left workspace. (1)  Expand 'Chroma Key' (2) and click the eyedropper icon in the same column as "Color". (3) Next, select the color you want to chroma key away by clicking in an area of your video with that color. (4)</p>

<p><img src="https://i.stack.imgur.com/BQ7xy.png" alt=""></p>

<p>Keep fiddling with your Chroma Keying settings untill you get the desired result. I found that setting similarity to around 7,5% (1) and Cutoff to around 50,0% (2) gave me a decent result.</p>

<p><img src="https://i.stack.imgur.com/gIxAY.png" alt="enter image description here"></p>

<p>Optionally add a few more video effects untill you get the desired result.</p>
 2836: <p>While chroma-keying is a good technique for dealing with solids, it doesn't work so well when dealing with transparent or semi-transparent objects.  Because the difference can be very subtle, you want to copy the difference instead or blend off luminance.</p>

<p>In Premiere, you can use the Set Matte effect to set a track as a luminance matte.  In the case of the sample of smoke from mmphilips post, the luminance was a bit low so I put it in a separate sequence and used curves to boost the overall luminance.  I then placed the matte on Video 3 and made it invisible.  I then placed the Set Matte effect on Video 2, pointed it at Video 3 and specified that it should use Video 3 as the matte.</p>

<p><img src="https://i.stack.imgur.com/fekDP.jpg" alt="Premiere"></p>

<p>The same thing can be accomplished in After Effects in a similar manner.  Again two copies are placed on the composition and the top most is made invisible.  The modes option toggles is clicked to bring up the proper controls and luminance is chosen for the second layer so that the third layer is used as a matte.  As shown, I applied curves to the third layer directly to make it blend more naturally.  Note that in this screen shot I actually inverted the matte layer and thus used inverted luminance, but those steps aren't necessary, I just made an error while getting it working and didn't bother to correct it.</p>

<p><img src="https://i.stack.imgur.com/etGw2.jpg" alt="After Effects"></p>

<p>Note how this results in much smoother results than a luminance key or chroma key since a luma or chroma key makes a hard cut off and is not able to do alpha blending based on the intensity of the smoke.  Smoke however is somewhat transparent and you want to be able to see through it where it is darker.  That's why this blending technique works.</p>
