3/5/12
10:48 am

MacMost Now 679: Creating Transparent Images With Pixelmator

Learn how to create transparent images for use in Pages, iMovie and other applications. You can cut out part of an image using the app Pixelmator and that part of the image becomes transparent and shows the items behind it.

Video Transcript (Click to Expand)
Hi this is Gary with MacMost Now, on today's episode let's look at using Pixelmator to create semi-transparent images.
One of the most common questions I get asked is how to create semi-transparent images, these are 32 bit images where some of the image is transparent and shows the background behind it. You can use these in applications like iMovie and pages and you need to create them in a graphics program. Now, in episode 423, I show you how to create them in preview, but it's a bit clunky. It's better to use a dedicated graphics program, like maybe Photoshop. Photoshop can be a little expensive a another alternative is a program called Pixelmator which you can get in the Mac App Store. Let's look at using that to create a semi-transparent image.
Now with Pixelmator you start off here, yes you do, you create a new image or open an existing one, let's open an existing one, um, and grab this one off the desktop that I've got here, it's just a photograph, and it opens it up here in a new document window. Now, by default, all images have a transparent background but, in this case, photograph completely covers it with pixels. So, I can erase part of the background simply by selecting a portion of it, select here, and pressing delete. Well unblock it first. Delete and you can see I have a transparent area right here, you can see the checkerboard pattern there which is universal in graphics applications for showing you there is transparency. Now I'll undo here and it's more likely I'll want to cut out, say the sky here. I can usually by choosing a lasso type of tool and selecting an area so I can just cut out around the house really roughly like that and then select the entire sky and then I can delete it like that. A good technique in just about all graphics programs is be able to adjust the selection so you can do that here in 'edit' and you can go to 'refine selection' and feather it. You can see it shows you here a rough estimate of the area so you can see how I'm kind of creating a more fuzzy area here of transparency. This works better if I would actually have selected a wider area, but I'll select 'ok' and now when I delete you can see it's kind of a fuzzy area, a fuzzy line between the transparent area and the solid area, rather than a solid, sharp line. Now the important thing is to now save it out in a format that supports 32bit transparency. So we'll do 'export', and in export here by default you've got JPEG. Now JPEG doesn't support transparency, PNG is the format you'll most likely want to use that'll support transparency. And I can export the PNG to the desktop and now I've got a semi-transparent image. Bring that out from behind me and you can see I've got the second one right here. If I double-click on it, it will actually open up in preview and you can see in preview it shows me this same checkerboard pattern behind the house which tells me that, it's transparent up there. Alright, so as an example let's look in pages here and I've got a blank layout document and I'm going to drag the PNG there and how do I know this is transparent? Because it's a white background, I'm just showing white there anyway, let's go and create a shape and a box shape like this, um, and then let's send it behind there and you can see that the transparent area shows the shape behind it. So here's another example in iMovie here, I've got some video let's, just drag a video clip in here. I have, um, advanced tools turned on. Here, show advanced tools so that means when I drag this photo from the finder onto the video I'll get all these extra options, I'll select 'picture and picture' and it will put it there, notice that the top of the house above it is cut out, it's transparent to the video. I can drag it here, I'll change the cropping too. If I do 'standard crop', you'll see what I get there, I can change the size. If I do 'fit', you can see that it's not going to obey the transparency, um, so I want to make sure that I choose 'cropping'. And also notice that if I choose 'allow black' then you can see that because this is a 4x3 photo but this is a 16x9 video you get the black bars on either side. So, I wanna make sure I disallow black and now I've got this and I can cut out a shape, inside of this, image or any image and it, all the transparent parts would show through and all of the opaque parts will be on top of the video.
So that's how to use Pixelmator to create semi-transparent images, hope you found this useful, till next time this is Gary with MacMost Now.

Comments: 4 Responses to “MacMost Now 679: Creating Transparent Images With Pixelmator”

    Patrick
    3/5/12 @ 8:27 pm

    Thanks, very helpful. I have Pixelmator and have used it to cut out backgrounds before. But I was unaware of the feather option on refine selection.

    Also, I haven’t used iMovie for several years (after they ripped out my heart, threw it on the floor, stomped on it, and laughed with that f%$k*^ing update). But maybe I’ll give it another try.

      Jean
      3/8/12 @ 7:00 pm

      May I know how the update made you so miserable?

    ~Joan.
    12/5/12 @ 5:02 pm

    As always, find your videos very helpful. Wondering if you recommend Pixelmator over Aperture, and if so, why? Would also greatly appreciate your doing videos on Aperture. I could use some help in finding my way around that program.
    Thanks.

      12/5/12 @ 6:42 pm

      They are very different programs. Pixelmator is an image editing tool, like Photoshop. Aperture is a photo management tool (storing and managing large collections of photos), like iPhoto. I may do videos on Aperture in the future. But most Mac users would be using iPhoto.

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