Darby Edelen
Forum Replies Created
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[Jim Arco] “How about a brainstorm for Lab color?”
Levels Adjustment Layer, set the Output White to ‘0’ for any channel you don’t need. Come to think of it that should work for any of the situations you’ve mentioned thus far.
Darby Edelen
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[Jim Arco] “Channel Mixer seems to only work for the current frame and is grayed out for smart objects.”
Channel Mixer Adjustment Layer?
Darby Edelen
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[Jim Arco] ” Thanks, Darby for several solutions. I guess I wasn’t specific enough. I really want to be able to save an image sequence of a given channel in any color space… so maybe a sequence of the K channel from CMYK, for instance.”
Did you try the Channel Mixer? That should work in CMYK.
Alternatively you can fill a layer with 100% K and set it to the Linear Dodge (Add) mode.
Darby Edelen
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I’d duplicate the footage, apply Color Correction > Channel Mixer to the top layer and Color Correction > Levels to the bottom.
Then on the bottom layer reduce the Red output white to 0 in Levels (removing the red channel from the source).
Now rebuild the Red channel using the Channel Mixer on the top layer by setting the Red-Red to around 25, the Red-Green to around 135 and the Red-Blue to something around -70. All other properties of the Channel Mixer should be 0.
What this will result in is a Red channel that is a weighted blend of the Red, Green and Blue channels. Since there isn’t much information in the source Red channel we’re weighting that lightly (Red-Red 25), this will keep some of the original red information. Since the Green channel has a lot of information (and it’s not the Blue channel) we weight that heavily (Red-Green 135). Because we don’t want the blue water to get red we also subtract information from the Red channel where the source Blue channel was intense (Red-Blue -70).
You should be aware that these 3 numbers add up to 100. If they add up to more than 100 then the Red channel may look too bright, if they add up to less than 100 then you’re not adding much Red. However, in your case (since there is so little Red in the source footage) you may benefit from increasing the Red-Red contribution in the Channel Mixer.
Finally set the top layer to the ‘Add’ blend mode to add the new Red channel back into the source Green and Blue channels.
Here’s a sample AEP where I’ve also added a couple of final adjustments for a nice look:
Darby Edelen
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Also there’s the Channel Mixer adjustment layer. That would give you even more flexibility.
Darby Edelen
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Expanding or contracting one side of a rectangle is going to necessarily introduce distortion unless the software has a way to scale the contents of the rectangle adaptively across the rectangle to reduce horizontal distortion without scaling the bounds of the rectangle. I would guess that this is not as trivial as one might think.
Darby Edelen
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Also it appears that expanding the left side instead of shrinking the right side will not cause as much distortion. You can scale the entire image down in the same transformation to get the size you want. Net effect would be similar to shrinking the right side in perspective but without nearly as much distortion.
Darby Edelen
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[chris brett] “…… if I duplicate a pre-comp and alter the settings of the copy it seems to alter the original as well ….
……………. sometimes anyway — but not always …”
Every item in the Project Panel is a source asset. Duplicating in the Project Panel will create a new source asset that After Effects treats separately from the source it was duplicated from.
Each source asset can exist in dozens (if not hundreds) of places in one or many compositions in a project as ‘duplicates.’ However, the layers in a timeline of a comp are references to the source asset and will change if the source asset updates. If you modify the source asset this change will exhibit itself wherever that asset is used in the project.
Darby Edelen
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What you’ve done in the image you posted is blended a white gradient with transparency into your image. If you look at the layer thumbnail in your layers panel you may notice that the one on the left (the color data for the layer) now has a white gradient overlaid on it while the thumbnail to the right (the mask for the layer) is still all white.
What you’ll want to do is select the layer mask thumbnail and then use the gradient tool with a black to white gradient (no transparency). Your image will become transparent where the gradient is black and remain opaque where it is white.
Darby Edelen
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Multiply the video by a 100% red color layer to get only the red channel.
You could also do that with layer styles.
Darby Edelen