Applying an Alpha Channel

Hello
Am I applying the Alpha channel correctly?
I made a title in AE (Black background, white text and a lens flare). I output it as an AVI (RGB Alpha) file and imported into my Pr project. The only way I can seem to make it work is by clicking 'opacity' in 'Show Clip Keyframes' and setting the 'blend mode' to 'screen' in the 'Effects Control'. However the lens flare looks a bit washed out/ transparent(ish).
Am I doing this right???
Cheers,
Ossie

Try exporting your Comp with alpha just as you did ....but turn off the Black BG layer.
There is no point to the BG (solid) as well as an alpha channel.
Put whatever bg back in ..in PPRO if you need one at all.
I assume you want your title and flares only without the black

Similar Messages

Photoshop CS6 using javaScript to truncate alpha channel name

Hello,
I'm a production artist and I work with PSD files that were created in Adobe Scene7 Image Authoring Tool. These PSDs contain a background layer along with 1-20 alpha channels. My script has to make a new blank layer for every alpha channel in the document. Then it fills the new layer with light gray. So far, my code accomplishes this. However, I'd like to apply the name of the alpha channel to the layer, but I need the name to be truncated. Every alpha channel starts with one or more characters followed by a backslash and then finishes with one or more characters. Here's an example:
An alpha channel might be named: Floor\floor
In this example I need my layer name to be just: floor. This means all character to the left of the backslash, including the backslash itself needs to be discarded. I was using the subSring() statement to do this. When I try to step through the code, line by line in ExtendScript, I immediately get an error that says Unterminated String Constant and Line 31 of my code is highlighted. I suspect it doesn't like the way I wrote the backslash character, although I surrounded it in double quotes to define it as a string.
Can anyone tell me why I'm getting this error?
Below is my code with lots of comments to walk you through the process. I wrote where the error occurs in red type.
I'm new to JavaScript so I'm not sure my while loop is accurate.
#target photoshop
// The #target photoshop makes the script run in PS.
// declare variable to contain the active document
var myDoc=app.activeDocument;
// declare variable to contain the number of alpha channels, excluding the RGB channels
var alphaChan = myDoc.channels.length - 3;
alert(alphaChan + " alpha channels exist");
// create loop to make new layers based on number of alpha channels, fill layer with gray and apply alpha channel name to new layer
for (a=0 ; a<alphaChan ; a+=1){
// make new blank layer
myDoc.artLayers.add();
// fill blank layer with gray
var color = new SolidColor();
color.rgb.red = 161;
color.rgb.green = 161;
color.rgb.blue= 161;
myDoc.selection.fill(color);
//variable stores alpha channel name
var alphaName = myDoc.channels[3+a];
// variable stores lenght of alpha channel name
var lz = alphaName.length;
// declare index variable to initialize position of 1st character of alpha channel name
var x= 0 ;
// truncate alpha channel name by removing all characters preceding the "\" symbol
while (alphaName.subString(x) != "\"){          (ExtendScript gives an error for this line and highlights the backslash and surrounding quotation marks)
    alphaName = alphaName.subString((x+1),z);
    x+=1;
    z-=1;
return alphaName;
// remove the backslash from alpha channel name
alphaName = alphaName.subString((x+1),z);
// apply truncated alpha channel name to corresponding layer
myDoc.artLayers[a].name = alphaName;

while (alphaName.subString(x) != "\"){
should be
while (alphaName.subString(x) != "\\"){

No alpha channel when BCC lens flare applied

Hello
With the help of Andy Neil, I created a light sweep for a lighthouse logo. I added a BCC RT Lens Flare Adv filter to enhance the effect of the light sweeping past the viewer. I looked great.
Then I got to thinking that the lighthouse logo with light sweep would make a great lower third, so I scaled it down to logo bug size and superimposed it over a lower third background.
The problem is that the inclusion of the BCC Lens Flare filter seems to add a black layer over the entire movie so that the lower third cannot superimpose over my talking head. I know it's the BCC Lens Flare because when I deactivate the filter and export, the alpha channel is present and the lower third is superimposed over the footage.
I've tried exporting with Lossless+Movie Alpha and Animation,
My question: Can anyone tell me why this is happening and how I might be able to remedy?
Thank you,
Blake

Yes, the lens flare is the problem. The generator is rendered as a blend mode which blends only with the elements in the project. The blend doesn't export as transparency because a blend mode is only transparent when combined with another layer.
Here are your solutions:
1) Composite the lower thirds with the video in Motion. If the bkg layer is in Motion, then the ADD blend mode applied to the lens flare will work properly.
2) Create an alpha matte layer. This requires you to create a black and white image of your project that defines transparency for your lower 3rd. Export that as well, and then do a Composite Mode-Luma in FCP.
3) Apply a Luma Key to your lens flare before export. This works, but is imperfect because the filter will inevitably key out some of the not-so-bright aspects of the lens flare, leaving you with a diminished result.
4) (My Suggestion): Apply the lens flare in FCP. FCP contains the SAME lens flare generator used by Motion. This will give you the best possible result with the least amount of extra work on your part.
Andy

What codec to convert .MXF and MP4 files into to use with alpha channels in Ae and Pr CS6?

When I import .mxf File, shot on a Canon C300, into after effects, the alpha channel options are greyed out, when I look in, interpret footage, main. This also is the case importing .MP4 files, shot on a Gopro hero 3. I used to use final cut and using compressor convert the files to pro res 4444 or 422. What's my new workflow for preparing files with alpha channels to use in After Effect and Premiere and do I use Media Encoder to do it?

When I import .mxf File, shot on a Canon C300, into after effects, the alpha channel options are greyed out, when I look in, interpret footage, main. This also is the case importing .MP4 files, shot on a Gopro hero 3.
Better question: Where do you expect that Alpha channel to come from and contain any useful info for transparency? You're making a fuss over a non-issue. Unless you apply keying or other methods of creating transparency, even if there were an Alpha channel it would be fully opaque and then what's the point?
Mylenium

Unexpected Alpha channel behavior in Premiere

Is there no way to interpret alphas as straight versus premultiplied in Premiere? Why do my transparent layers and clips with alpha channels display differently with a Black Video layer below them?
Background info:
I'm exporting my film to files with codecs that support alpha channels, not because I want an alpha in the result but because I need full RGB / 444 color coding for digital cinema theaters. I'm using ProRes444, Targa and PNG Image sequences to preserve as much quality as possible in my master exports.
I've discovered that there is no option to disable the alpha transparency in the Export Media step while preserving at least 10 bits per color channel (Trillions of colors in AE).
To solve this problem, I've had to add a "Black Video" clip to the first video track, underneath the film's content. When this is done, the pre-rendered text elements with alphas look different. They are movie trailer style text treatments that are light text over pure black. (I'm on my ipad right now and don't see a way to upload screen shots to show examples)
The result with the black video layer applied at the bottom is similar to the way QuickTime 7 displays straight alphas incorrectly. This problem occurs with both straight and premultiplied renders. The rendered text is from after effects and is stored using the animation codec.
I'm aware of how to work around this, by maintaining the alpha transparency in Premiere and then removing the alpha channel of my export by running it through After Effects, but that is a ridiculous, time consuming step.
I'm working with the GPU Mercury Engine on with a K5000 from NVIDIA. Can anyone explain this behavior? Is there no way to interpret alphas as straight versus premultiplied in Premiere? Why do my transparent layers display differently with a Black Video layer below them?
Here are the screen shots
UNDESIRED EFFECT using Black Video layer at bottom: Notice the fuzzy glow surrounding the text. This is happening with both straight and premultiplied renders.
INTENDED LOOK when composited over nothing: The glowing edges are displayed the same way in Premiere as in After Effects.

In my understanding, the reason 444 is indicated is because they are not RGB codecs. They simply sample the same amount of color as is possible in true RGB codecs. They still require a conversion from RGB to YUV for coding to a file, which almost always introduces a very slight shift in values, though usually imperceptible or acceptable. If the codec is truly RGB there is no need to indicate luminance vs color sampling.
...I think.
Again thank you for your awesome input! You've been a huge help here on my day off. :)

Alpha channel edge (AE to FLV)

Hi all...
i'm importing a png sequence into AE
from AE i'm exporting composition directly in FLV and importing into Flash.
PNG has alpha channel.. when inserting into Flash all objects appear with a white edge on alpha channel
All parameters are quite standard (OnVp6, 700 kbps, no audio... )
no filters are applied to AE layers...
tried with render through MOV Animation and then into FLV but nothing changes...
here a screenshot of the problem...
any solution for this problem??
thanks
Ivan

See this post about alpha channels in Flash and FLV files.

Getting alpha channel to export from AFX to Photoshop

I have an image in After Effects CS4 with some text on it and a transparent background. I need to export this as a png (retaining the background transparency). I've tried to do this in many ways (as single frame or as png sequence after reducing work area to my single frame, and as prematted or straight alpha (both with RGB 16million Plus) . . . but I keep getting a black matte in background. Tried exporting both as png and as photoshop file.
Can someone explain the correct way of doing this? (The alpha channel does transfer to photoshop, so if there's a simple way to use that to mask out the background (or mask in the part of the picture I need) I guess that would suffice. It was just mean I need to make my text brilliant green or something in AFX and then convert to black in photoshop.
Is this some kind of bug or am I just missing the simple way to do this?
Thanks for any help.

Thanks Mylenium.
Can you explainyour method in more detail.
I double clicked the later title to create a floatin layer.
Then I went into Channels and CTRL clicked no the alpha layer which makes a selection of the correct portions of the image.
Clicking delete (or inverting selection and then clicking delete) doesn't get rid of everything.
Can you spell out what else I have to click on first - do I go back to the regular image in layers and then hit delete or apply my selection as a mask?
I did manage to fumble through things once, but if you don't mind spelling out the right method, I'd like to learn the right way.
Thanks

Tiff files with Alpha Channels do not display or print correctly...

I have Tiff files that have been edited in Photoshop that do not display correctly. As far as I can tell this is caused by the existence of Alpha channels in the channels panel in PS. When the files are imported to Aperture, they only display information from either the alpha channel or a layer using that alpha channel as a mask.
If this is true, what are people doing about it. This cant be acceptable???
Are there any work arounds and is apple addressing this problem?
Can anyone else confirm this?
I am using Aperture 1.1.2, OS 10.4.7 and PS CS. on a Dual 2GHz Power PC G5 with 4.5 GB RAM
Please note, these are NOT .psd files. I have read and am aware of some psd compatibility issues, and have checked the maximize compatibility in PS.
-Sol

Thank you for your response, I am trying to figure out what to do differently when we re-create the PDF so we don't have font issues when we combine. I don't want to keep recreating the problem, I am looking for a solution. Why does this happen? What settings do I tell other to apply on their Acrobat? Is the a font issue in Adobe? I found this on a Google search on the internet and can't seem to get it to work on XI PRO.
Embedding fonts into Acrobat 9 through Distiller:
Launch Acrobat.
Choose Advanced > Print Production > Acrobat Distiller.
Select Standard in Default settings.
Go to Settings and select Edit Adobe PDF Settings.
Select Fonts and in the font source window select the fonts you want to Add.
Click Save As and then OK.

LR import with alpha channel

<Lightroom novice> Can I import a tif image with a alpha channel in it? It seems as though LR will accept the image and allow development but when I export it as tif or psd it goes out as RGB only - the alpha channel is gone. I don't really "need" to do anything with this channel in LR but I can't have it disappear either. Maybe a import/export setting issue - I hope so...

TLL... wrote:
"All file "edits" are kept in LR's catalog, which should be backed up along with the unmodified "original" files."
OK, got that too. We probably won't save this once the exported images are approved and backed up.
It sounds like you don't need LR's database tools for organizing, adding metadata, or the various Export modules. You could still use LR to expedite Development editing of the RGB image. One possible solution is to Export the LR edited RGB images full size to a separate folder with the same bit depth and colorspace as the original files. Then use a PS Script to Batch Merge the LR export image to a new layer in the original file, something similar to this one:
http://forums.adobe.com/thread/546727
This way you still have the original RGB image backed up as a layer, which can also be unselected in the merge script.
TLL... wrote:
"At a later date the Alpha Channel information can be applied "non-destructively" in PS using editing layers to "blend" the IR image data."
This is where I'm getting lost. Are you talking about stripping the 'original' alpha channel from the pre-LR image and inserting it into the LR processed RGB image via PS batch/script? That's my thinking as an one approach.
"These PS modified files can be re-opened in LR and will now show the applied Alpha channel editing layers. Make any further edits you desire in LR and use the most appropriate LR module to "tailor" the output for your specific usage."
No they won't, or do these steps involve only psd files w/alpha channels? The alpha channel (IR data) is still ignored by LR, I have no way to even just keep that information once inside LR nor can I "taylor" a way to save an image with 4 channels of color information inside LR.
I have no idea what you will be doing with the Alpha channel IR image data, but I was suggesting to convert the Alpha channel to a layer mask in PS with 'Blending.' This leaves the Alpha channel as a backup of the IR data. Here's a simulated example using a an IR layer mask I created using LR's B&W IR Develop preset:
You can use PS actions with the Batch processor and/or build scripts to do just about anything. In LR you can create Develop presets to apply adjustments across 1,000s of images with a couple of mouse clicks, but no Actions or scripting capability. Like I said, PS & LR are complimentary, but different. I'm not sure which processing methodology is best for your image "end-use" but I hope this gives you some more ideas.

Motion tile a video with an alpha channel

Hi!
I'm trying to use the motion tile effect to fill transparent edges that are the result of stabilization with the prodad mercalli plugin. The problem is however that because the stabilization hasn't been done using keyframe movement in AE, it sees the transparent edges as part of the frame and applies the motion tile so that the transparent areas stay intact. In other words the motion tile effect doesn't see that the image is moving around because only the alpha channel is changing.
Is there any smart ways to solve this problem in AE so that I can apply the motion tile effect to get rid of the alpha transparency around the edges of the stabilized footage?
Any help will be appreciated!

Hi and thank you for helping out!
Unfortunately I didn't get this to work with shift channels. I'm not sure what you meant by separating the components? I put shift channels on the videoclip and told it to use alpha from the video of the alpha.
Actually I'm a bit confused on why shift channels should help. The way I see it, the problem is that the "motion tile" effect is seeing the "whole" pixel dimension of the video that also includes the alpha channel and is applying itself to the whole frame instead of just the opaque area (the actual stabilized video). Because of that the motion tile effect is tiling the whole frame, including the alpha of it which leaves transparent gaps between the two tiles.
Maybe there was a miscommunication between us or should I just try the shift channels effect again? If that's the case, then could you explain what you mean by separating components?
Thank you very much!

Alpha Channel in Photoshop for iWeb instant Alpha?

Hi,
Recently i wish to Make a Picture's Background to transperence.
I try to use a ODD color (green screen's GREEN) as background color so that it'll be easy to delete the background when apply the instant alpha function...but i relize that it doesn't really make sense at all...Most of the parts doesn't process well...
Question:~
+ What s'ld i do in Photoshop before i bring the picture file into iWeb for instant alpha?Alpha Channel and save as .psd?
+ Do any other useful way to solve the issue above?
Thanks!!

Here's what I do:
1 - open the file, double click on the background layer in the Layer pane to unlock it and add a second layer below the original layer.
2 - using your tool of choice delete the background you want removed. If the background is a single color I use the Magic Wand tool. You may have to work with the Tolerence number if there's any gradiants. Other wise I use the Quick Selection tool (again you may have to set the Tolerence level)
3 - When he background is removed you then use the File->Save for Web and Devices option.
4 - in the next window select PNG8 under Preset and check the Transparency box. Colors is set to 256, Dither at 200% and Web Snap 0% (these are all the defaults the first time I used it).
5 - The background should show transparent. It it doesn't click on the color that you want transparent in the Color Table and then click on the far left box in the toolbar directly below the color chart. You can add additional colors if desired.
6 - Save and you're done.
OT

Transparent alpha channel in flv not working

Bringing a raw avi file into Premiere Pro 2, I applied a
color key effect to the background to make it transparent. I then
exported it as a flv file using Adobe's Media Encoder. The video
codec was set for On2 VP6 with the "encode alpha channel" box
checked. Importing this flv file into Flash 8 using Progressive
download in the wizard, I placed the flv on layer 2 and a
background image on layer 1. When I play it, the background image
pops up, then the flv, but the background image doesn't show
through the transparent area of the flv. Any suggestions on what
I'm doing wrong?

Did you ever figure out what the fix is for your problem with
transparent video? I'm having the exact same issue and have tried
everything -- still no transparency (although my keying was done in
AE).

Problems with Photoshop Alpha Channels

Hi all
Got a job where I want to use alpha channels to cut-out some images in Photoshop and then put them into an ID frame with a black background. Want to use alpha channels rather than a clipping path as I need the edges to be feathered (have applied 2 pixels of feathering to the selection in Photoshop before saving it).
When I do this and drop it into Quark it looks good but when these images are dropped into ID and then the alpha channel is turned on, with the default Threshold and Tolerance settings, it doesn't look good. It looks like a rough approximation of my alpha channel, all the fiddly bits and bezier curves in the selection have been smoothed out and the feathering has gone. Playing with the settings doesn't really seems to help either. If I turn on the alpha channel in the import options when importing then it comes in as expected but I have quite a few images already in the document that I need to turn on the alpha channels for.
Both PS and ID are CS3. I've tried saving the images both as PSD and tif. Anyone got any ideas? Seems odd that when I import an image with the channel on I can't go to the clipping options and tweak the settings.
thanks,
Iain

Thanks for your reply Bob. I've confused things with my terminology I think. We're drawing a path round the image, using bezier curves where appropriate, making that work path a selection (feathering the edge in the process) and then saving the selection (as an alpha channel) and then using the feathered alpha channel in Quark/ID to knock-out the background. Not keen on using a PSD with a transparent background at the moment as these are just test files while we show the customer what it will look like if we do cut-outs. We are making a couple of different alpha channels per image, with different settings, which would mean multiple files if we used your method I think. Maybe once we get the approval from the customer we could use PSDs as you describe but I was just wondering why the options for affecting alpha channels after importing the image aren't working as I expected.
Iain

BitmapData masking: how to merge 2 alpha channels?

How can I apply an alpha mask from one bitmapdata to another? In other words, I want to merge the alphas, not simply copy one alpha channel to another bitmap.
Here's an illustration:
Notice that both the triangle and the ellipse have alpha channels, and the result is an intersection of these alpha channels. The RGB channels from the second image are used, and discarded from the first.
I've looked into using BitmapData/merge(), draw(), copyChannel(), but they don't seem to do what I want. Anyone?
Cheers.
-Aaron

Aha, looks like the answer was right under my nose: copyPixels() can do exactly this:
If you include the alphaBitmap and alphaPoint parameters, you can use a secondary image as an alpha source for the source image. If the source image has alpha data, both sets of alpha data are used to composite pixels from the source image to the destination image. ThealphaPoint parameter is the point in the alpha image that corresponds to the upper-left corner of the source rectangle. Any pixels outside the intersection of the source image and alpha image are not copied to the destination image.
Cheers.
-Aaron

Can I specify a color that will be treated as an alpha channel

I have a CS5 illustrator file.
I want to create an Oval that will have a unique color that would be treated as an Alpha channel.
No other part of the drawing will have this color.
Can I "tell" illustrator that the oval is "alpha" -- and basically have adobe premiere cs5 see the oval as transparent.
Thanks
Rowby

Not necessary to make a color specific any clipping mask will work that way and so will any file from AI as long as it has pdf compatibility enabled.
But for what you want to do you can apply the clipping mask the oval shape to the layer level.
Draw the oval shape with out any other objects drawn on the specific layer you want to use as a mask, then at the bottom of the layers panel the first icon on the left side will make that a clipping mask for that layer anything drawn after will me masked but will not mask art from other layers.
Very handy and you can have more than one by placing them on different layers and have them work this way for those layers as well.
You can clipping masks applied to groups and objects as well and when th file is brought into PPro it will treat it as if it were an alpha channel mask.
Here are two screen shots
This is what it looked like in AI
Illustrator has been used this way since I believe the first version of Premiere.
As far as PPro is concerned Illustrator has no background which is true.

Applying an Alpha Channel

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