Exporting Instant Alpha Image for other uses

Question

Level 1

8 points

Exporting Instant Alpha Image for other uses

In Keynote '09, the option key added to Instant Alpha selects non-contiguous colored areas. In this instance, I have a skeleton on a white background. The above method does a nice job of getting the white background out of all of the nooks and crannies of the rib cage. However, I can't find a way (using only system tools) to get that image out with the alpha channel intact (for example, to build a library of background-less images). I know I can do it in Preview, but Preview, inexplicably, doesn't allow for the use of the option key for non-contiguous areas. And going in one nook or cranny at a time is tedious. I know I can do it in Photoshop, but I'm a technology teacher for a school district and most teachers don't have access to that. Does anybody know a way to use Keynote's Instant Alpha tool to create a library of background-less images? Thanks for any help.

Dual 2.6 GHz Mac Pro, Mac OS X (10.6.6)

Posted on Feb 8, 2011 9:14 AM

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Answer 1

mflider

Level 2

283 points

Feb 8, 2011 10:22 AM in response to fmaggi

You can use a combination of Keynote and Photoshop to create a PNG image with alpha:

1) Instant Alpha an image in Keynote.
2) Copy that image in Keynote.
3) Switch to Photoshop and create a new document (cmd-N) (Photoshop should automatically suggest the right size of the new document, if the Clipboard preset is selected in the New Document window).
4) Paste into Photoshop (it will come across as a Vector object; that's ok, just paste and press the return key).
5) Delete the existing background layer.
6) Save as a PNG or "Export to Web" as a PNG-24

Done!

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Answer 2

fmaggi Author

Level 1

8 points

Feb 8, 2011 10:35 AM in response to mflider

Thanks, mflider, for that, but for most of our teachers, Photoshop is not an option. That's why I'm looking for a workflow using system tools (they do have iWork), but doesn't require visiting every nook and cranny of an image, like in my example above. But I do appreciate the response.

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Answer 3

fmaggi Author

Level 1

8 points

Feb 8, 2011 12:26 PM in response to Kelly Coull

Kelly, that is definitely a step in the right direction. I assumed the PDF created in Preview did not have alpha intact because it came in with a white background. I tested bring it into Pages and it did indeed read the alpha channel (in Photoshop too). It does have limitations, though. iMovie '09 will not accept it, for example. If you do a Save As in Preview as a .png (iMovie takes that), it doesn't preserve the alpha channel. You're back to scraping the nooks and crannies in Preview again if you need it in iMovie.

But having it available in Pages is a big deal. I'm going to click question answered, but I would love any other ideas that may be even more broad based. Thanks for the info.

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Answer 4

Kyn Drake

Level 7

21,597 points

Feb 9, 2011 6:03 AM in response to fmaggi

Try Preview. It's free, It has Instant Alpha PLUS a Smart Lasso that you can use to select the area you want to remove. Just perform the action you want (the options are under the "Select" toolbar object), press "Delete" to remove the selected area, then, when you Save as png, it automatically adds the Alpha channel.

Preview's limitation is that it will only let you perform Instant Alpha on a bitmap. Anything you copy from Keynote to Preview automatically gets converted to a PDF, so it's no go. You'll have to bring in the image from it's original location (on your HD for example) to Preview directly. If you don't have access to it, then it's a two step process. First, copy the image into Preview, then save as .png (since it's lossless), then open that png and apply Instant Alpha.

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Answer 5

fmaggi Author

Level 1

8 points

Feb 9, 2011 8:29 AM in response to Kyn Drake

The problem in my case, Kyn, is that Preview doesn't allow for non-contiguous selection (Keynote allows for the use of the Option key to do that). In my example of the skeleton, that means many trips into the rib cage to get a finished product. A real pain. In Keynote, 2 seconds and it's done. It would be nice if there was some dialog between the development teams. Thanks for your reply.

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Answer 6

Kyn Drake

Level 7

21,597 points

Feb 9, 2011 11:13 PM in response to fmaggi

Got it! Go to the Mac App Store and download "Image Tricks Lite" for free. Create the Instant Alpha in Keynote, copy, paste into Image Tricks Lite and save as PDF. I just tried it and it appears to work well, but wondering how it would work for you.

If you don't have the Mac App Store, you should still be able to download it from their site.

http://www.belight.com

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Answer 7

Feb 10, 2011 6:26 AM in response to Kyn Drake

Thanks for the tip Kyn. Image Tricks Lite also allows it to be saved as a .png and keep the transparency which is what the OP was looking for. Any idea why in Preview if you save as a .pdf it keeps the alpha, but .png does not?

You forgot the soft on the website, so here is the link again [http://www.belightsoft.com/main.php].

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Answer 8

Kyn Drake

Level 7

21,597 points

Feb 11, 2011 5:15 AM in response to Kelly Coull

Ah, sorry about the URL 🙂

I believe it's because Preview isn't written to recognize the transparent area in a .pdf and convert it to an Alpha channel for .png (though I was sure this used to work in the earlier days of OSX). You'll notice that, if you have a transparent .png on the clipboard that you paste into Preview, it will indeed keep the transparency. You can tell because when you try to save as .png, you have the option to include the Alpha channel.

Try copying the X from the palm of the character here

http://web.mac.com/makentosh/tipsfromtheiceberg/Blog/Entries/2006/8/4Stop_RedX.html

or the number "30" from here

http://web.mac.com/makentosh/tipsfromtheiceberg/Blog/Entries/2010/5/22That_Lady_fromBefore.html

You'll see that Preview is able to handle transparency for bitmaps just fine.

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Answer 9

fmaggi Author

Level 1

8 points

Feb 11, 2011 8:07 AM in response to Kyn Drake

Thanks all for the extended discussion. I did download Image Tricks, but it didn't work for me. I copy/pasted from Keynote then Save As...PDF. Dragged the result into Pages and white background. Did it again with Save As...PNG and same results. In neither dialog box did I see any reference to transparency (as is in the Preview box when saving a .png file with transparency). Am I missing something?

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Answer 10

Kyn Drake

Level 7

21,597 points

Feb 11, 2011 6:45 PM in response to fmaggi

Let's try a few specific steps and see if it works.

1) Go to this page

http://www.makentosh.com/tipsfromtheiceberg/Blog/Entries/2008/7/20Clip_a_little_Web_for_you_files/shapeimage3.png

and copy that .png. Then paste it into ImageTricks Lite. In ImageTricks, you should see that the area around the pickle is gray. This indicates that it's handling the transparency properly.

2) Take the same .png, copy it and paste into Keynote. It should paste in as something like shapeimage_3.tiff (you can see the name in the metrics pane of the inspector). If you see a transparent area around the pickle there, then we know that things on your end and mine are similar.

3) Now go to this url

http://www.asianinvasionsaloon.com/redand_whitedots.jpg

And copy and paste that into Keynote (it should appear as red and_whitedots.tiff).

4) Use the option key with Instant Alpha to remove the white dots from the red fabric.

5) Click to set the effect, then Copy and Paste into Image Tricks Lite.

If things go as I'd expect, you would see that the image would paste into Image Tricks Light, but the dots would be gray indicating it's transparent at those areas.

Now, save as .png, and the file that you save to your system should retain the same transparency when you drag it into a Keynote, Pages, etc. doc.

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Answer 11

Feb 8, 2011 11:32 AM in response to fmaggi

Do all your instant alpha in Keynote then copy. Open Preview and command n +(or File>New from Clipboard)+ and save as a .pdf. This will keep the alpha.

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Answer 12

Kyn Drake

Level 7

21,597 points

Feb 9, 2011 10:10 AM in response to fmaggi

Ah, there's something I didn't know 🙂 I've got other free tricks, though. I'll try other solutions when I get home today. I enjoy the challenge of finding these free workarounds.

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