Posted by Gary Rosenzweig on 2/23/09.
You can follow Gary on Twitter.
Use the Preview application that comes with Mac OS X to cut out a person or object from a photo and make the rest transparent. You can use this to make better images for social network profiles, Pages documents or Keynote presentations.
Video Transcript (Click to Expand)
On today’s episode lets learn how to use Preview to cut out part of an image and leave the rest transparent.
For those of use who have used Photoshop and other tools like that know that this is a pretty common thing. You want to take a person that’s in an image and cut them out or some object in it and cut it out and leave the rest transparent. Make the background transparent in other words. There are a lot of different uses for this. For instance, you can use it to cut yourself out of an image and use that as an icon for one of the social networks like Facebook. There’s a lot of other uses. But this, you know, you can do it with the Preview tool that comes with Mac OSX 10. The Preview is full of surprises and here’s how to use it to go ahead and cut out somebody from an image.
Ok, so here’s an image of me that I just pried out of my iPhoto library. Now it really helps to have a high-resolution image, so something form your iSight probably won’t work. You want something from your digital camera, 5 mega pixels or higher, so that you have a lot to work with for removing pieces of the image.
The first tool we’re going to go ahead and use is up here in the selection tools and it’s called instant alpha. What happens, is you grab the little pieces draw basically little lines
on the screen and it grabs the colors in that area and it will highlight them in red and then remove them. And continue to grab different areas of the image. Now this is going to be a difficult image to work with because of those shadows there behind me. They’re going to go into my beard like that and it’s going to be very hard to remove. You can do a pretty good job though and get rid of a lot of it.
So a better way to do it might be to actually go ahead and start again here. So to use this method it’s called the extract shape method. It’s the same place; it’s the one right above it there. And what you do here is you want to draw around the shape you want to extract. You’re going to draw this red line here. And you can release your mouse and click it again to continue to add to the line. It won’t complete the shape until you get all around and connect back to the original piece. So you want to kind of outline what’s there the best you can. You can zoom in, definitely in the preview window there, and get little bit more accuracy. But you’re going to have chance here in a second to go ahead and make it even more accurate when you’re done drawing the initial shape.
So you’re just going to draw straight across, connect it, and there we go. Now I get all these little dots, and I can actually manipulate these dots and move them around to kind of hone in the exact image I want. And again I can zoom in or leave it at this zoom here. And hit return and it will cut out everything except what’s there.
So the great thing is here I have an image now basically of me that has no background around it. I can use it as a nice icon on Facebook or something else. You can see that it’s kind of rough around the edges like around my ears, but this is where the high resolution comes in. Because I’m not going to use it at this kind of resolution, I’m going to go ahead and save out of Preview in a different resolution. So I mean this thing may be a couple mega pixels still in size. I’m going to and save it in something really small like maybe 320×320 or 160×160, and you’re not going to see those little jaggies around and that’s the advantage of starting with a high resolution image. Now if you save the image out like a png file it will maintain the alpha transparency. In other words the transparent part will remain transparent. So you can go ahead and use it in something like Pages for instance and drop a graphic in there. So say you that have a picture of a product that your company makes and it has all kind of stuff in the background, you can cut that product out and make a nice transparent version of that and you can put that image into your presentation using Pages, you can use Keynotes, all sorts of things, and create a nice image for that. The key is the png that’s 32 bits instead of saving it as a jpeg that you might use on the Internet.
So that’s all for now, until next time this is Gary Rosenzweig with MacMost Now.
On today’s episode lets learn how to use Preview to cut out part of an image and leave the rest transparent.
For those of use who have used Photoshop and other tools like that know that this is a pretty common thing. You want to take a person that’s in an image and cut them out or some object in it and cut it out and leave the rest transparent. Make the background transparent in other words. There are a lot of different uses for this. For instance, you can use it to cut yourself out of an image and use that as an icon for one of the social networks like Facebook. There’s a lot of other uses. But this, you know, you can do it with the Preview tool that comes with Mac OSX 10. The Preview is full of surprises and here’s how to use it to go ahead and cut out somebody from an image.
Ok, so here’s an image of me that I just pried out of my iPhoto library. Now it really helps to have a high-resolution image, so something form your iSight probably won’t work. You want something from your digital camera, 5 mega pixels or higher, so that you have a lot to work with for removing pieces of the image.
The first tool we’re going to go ahead and use is up here in the selection tools and it’s called instant alpha. What happens, is you grab the little pieces draw basically little lines
on the screen and it grabs the colors in that area and it will highlight them in red and then remove them. And continue to grab different areas of the image. Now this is going to be a difficult image to work with because of those shadows there behind me. They’re going to go into my beard like that and it’s going to be very hard to remove. You can do a pretty good job though and get rid of a lot of it.
So a better way to do it might be to actually go ahead and start again here. So to use this method it’s called the extract shape method. It’s the same place; it’s the one right above it there. And what you do here is you want to draw around the shape you want to extract. You’re going to draw this red line here. And you can release your mouse and click it again to continue to add to the line. It won’t complete the shape until you get all around and connect back to the original piece. So you want to kind of outline what’s there the best you can. You can zoom in, definitely in the preview window there, and get little bit more accuracy. But you’re going to have chance here in a second to go ahead and make it even more accurate when you’re done drawing the initial shape.
So you’re just going to draw straight across, connect it, and there we go. Now I get all these little dots, and I can actually manipulate these dots and move them around to kind of hone in the exact image I want. And again I can zoom in or leave it at this zoom here. And hit return and it will cut out everything except what’s there.
So the great thing is here I have an image now basically of me that has no background around it. I can use it as a nice icon on Facebook or something else. You can see that it’s kind of rough around the edges like around my ears, but this is where the high resolution comes in. Because I’m not going to use it at this kind of resolution, I’m going to go ahead and save out of Preview in a different resolution. So I mean this thing may be a couple mega pixels still in size. I’m going to and save it in something really small like maybe 320×320 or 160×160, and you’re not going to see those little jaggies around and that’s the advantage of starting with a high resolution image. Now if you save the image out like a png file it will maintain the alpha transparency. In other words the transparent part will remain transparent. So you can go ahead and use it in something like Pages for instance and drop a graphic in there. So say you that have a picture of a product that your company makes and it has all kind of stuff in the background, you can cut that product out and make a nice transparent version of that and you can put that image into your presentation using Pages, you can use Keynotes, all sorts of things, and create a nice image for that. The key is the png that’s 32 bits instead of saving it as a jpeg that you might use on the Internet.
So that’s all for now, until next time this is Gary Rosenzweig with MacMost Now.
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Excelent!
I really didn’t know you could do something like that with Preview – this is one application that is constantly underestimated.
Thanks for your let’s-show-you-how-it’s-done-video! :)
A fun unexpected surprise. Thanks.
I showed it yesterday to an Apple One-to-One Instructor who was mildly astonished: “Preview can do that!”
Thanks MacMost! This episode has helped me VERY much!
how do you open the photo on preview to edit. it does not give the options you have explained?
Thks so much
Many ways. Run Preview and then choose File, Open. Drag and drop the file onto the Preview app (in the finder or doc). Ctrl+click on the file and choose Open With and then select Preview as the app.
Thank you, I messed with this for hours on my own and was unsuccessful until I found your video. Great job!
That was invaluable advice…I have been on the internet for hours trying to figure out how to cut-out photos!
Really useful, thanks very much!
What if I want to cut a hole out of an image so that the area inside the whole is transparent as well as the background? I am scanning the image of an actual CD to be used as the CD art for iTunes since I do not have the album cover. Thanks.
You could do that as well by selecting the area and deleting it. Or, in your case you could just fill it with white.