Join Maxim Jago for an in-depth discussion in this video Understanding pixel aspect ratios, part of Photoshop CS5 for Video Editors.
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I'd just like to show you a little detail about Pixel Aspect Ratios just so we're totally clear about this issue. If you're working with HD formats, you're probably using square pixel anyway. So, you can just forget about it, which for me counts as real progress. But there's some nice features in Photoshop to help you to deal with pixel-aspect ratios as well. So, I'm going to go to the File menu and choose New. And I"m going to take as a preset, film a video NTSC DV, which, if I look under the pixel-aspect ratio settings down here, under advanced is 0.91 to 1, so it's slightly narrow pixel shape for regular NTSC DV content.
This is non-widescreen you can see I've got various different sizes available, so I'll click okay on that. Now immediately I get the warning saying okay, you've got non-square pixels, and Photoshop's going to handle it, but it's just for preview purposes, so okay. And straightaway now I've got this window with some guides. And I'm just going to go to the View menu and I'm going to go to the Show option and I'm going to get rid of those guides. So here's my document. Now If I go to the View menu, I've got Pixel Aspect Ratio Correction turned on. And if I look at the Pixel Aspect Ratio option right now I've got the D1/DV NTSC 0.91 option.
And you'll notice there's various, these are pretty much all of the common standards available to me. Now, if I make another item. So I'm going to go file, new. And this time, I'm going to go for maybe a photo option. I'll go for transparent background again. And I don't really mind about the size. But the key thing here is that this is square pixel. I'm going to click okay. And here's my document Now, I'm going to go to this Ellipse tool here on my toolbar and, looking at the options for that tool which appeared when I have it selected.
I've got this set to draw our field in shape. That's fine. I know it's a square but I've got the Ellipse option selected and I'm going to click and I'm going to start dragging. Now, by default, this is going to make an ellipse for me but I'm going to hold down the Shift key And coincidentally, standard shortcuts in Photoshop include holding down the spacebar to move an item around. I hope you can see that okay. This is very, very good for making selections in Photoshop. And if I hold down the alt key or the option key on a Mac, then I'm drawing out the shape from the center.
Still, I'm just going to position a circle around about the middle of my image here. There we go. Now, what happens if I want to bring this circle into, if I click on the tab here, my non square pixel image. This would normally be a bit of a problem, you'd end up resizing the image to give it too many pixels, you just have to do the maths... Then you end up copying that into your non-square pixel document, and the non-square pixels shrink it or expand it back out. And really, I want to avoid doing maths as much as I possibly can. But Photoshop can handle this for me.
So one way I can do this, is, if I click at the very top of my window. I've got an arranged documents option. And now, because I have two documents. I've got my original untitled blank document. Actually, I made this with a white background, which I Didn't really need them, never mind. And here is my print document. I can now select a few different options for whether I'm going to view them side by side or above and below. And this used to be a bit of an issue in Photoshop, because you'd end up toggling between them. But I can now choose two up and I've got one item on the left and another item on the right. Now, if I go to the first item over here, it's just got one layer in there, but because I have these side-by-side.
I can simply drag the layer from the Layers panel over into the blank document, and it immediately, automatically, scales it to match the pixel aspect ratio of my DV image. This is, quite frankly, amazingly magical. If I go to the View options with this image selected. I'm seeing pixel aspect ratio correction for regular DV, NTSC.
If I turn that off, you can see I get a wide circle. And it's an ellipse now. Turn that back on. If I click okay. If I click back into my original item. You'll see that there is no pixel aspect ratio correction being used. But the images work out, because Photoshop has just magically done the maths for me. Now, I'm going to go back into the other document here. And I'm going to undo with Ctrl+Z. And in fact, I might need to go a couple of steps. Now, one of the things that catches a lot of people out with Photoshop. In fact, if I just redo. And if I just grab the paintbrush. And maybe I'll shrink that down a little bit. I'm using the square bracket keys here to increase and decrease the size of my brush.
And I'll just swap these over. I'm just going to draw little bit line of the dot. Now in Photoshop if you undo you just press Ctrl+Z or Apple Z as you would normally. But if I press Ctrl+Z or Apple Z now I remove the dot. If I press it again the dot comes back. And this a common way for people using Photoshop to work. It really caught me out when I first started learning Photoshop. Because I was wondering, how do I undo multiple steps? There's a History panel. And you can, you can go back, and back, and back with the history.
But if you want to use the keyboard, you're going to use Ctrl+Z or Apple Z plus, either the Alt key, or the Option key on a Mac. So in this case, if I hold down Ctrl and Alt and press Z once, I lose the dot. Twice I lose the line, and another time, and I'm going to lose that circle. So, Apple+Option or Ctrl+Alt for multiple steps of undo. Now, the other way I wanted to show you is if I choose the marquee in this document here. And I'm just going to click and drag to select a bit of my picture which has got the circle in.
I'm going to copy with Ctrl+C or Apple+C. Then I'm going to click into my other document and paste with Ctrl+V or Apple+V and again. Photoshop has automatically calculated and adjusted the size of the image to make it fit correctly. And just to show as well, if I go to my View panel, I'll just go back here to viewing a single image, if I got o my View menu I can change the pixel aspect ratio. Maybe I'll go for. NTSC widescreen. Now, just for clarity. Changing the pixel aspect ratio does not change the number of pixels in the image. All it changes is the shape of those pixels.
So, though it looks like my image has gotten bigger. Actually, all I've done is I've made the pixels wider. If I go wider still for full anamorphic. I'll just double-click on the hand here to zoom out a little bit. You can see it's gone even wider. But it's the same size image. It's the same resolution. This is just like if your working on HD Cam media which shoots 1440 by 1080 but actually is displayed as full HD 16 by 9 a if it were 1920 by 1080. Or DVC Pro HD for that matter. And just while we're looking at zooming in, I've got the Zoom tool here, and I can click and click and click.
Or, I can click, and drag left and right to zoom in and out. I've used the Preferences to set my scroll wheel to zoom in and out as well. But if you want a shortcut for seeing 100%. Double-click on the zoom tool here. And that will go to 100 percent. The hand tool is for moving around inside the image. I imagine you'd be familiar with this if you've ever seen Acrobat. But you can double-click on the hand tool to have the image fit within the visible area. So you can see here, I've got exactly. 65.14%.
In fact I can click in this box and type in maybe 50% and get any size I want as well. So thats just a little note about pixel aspect ratios and the way that Photoshop handles them.
- Color modes, pixel shapes, and interlacing
- Working with prebuilt templates
- Understanding layers
- Using Smart Objects
- The alpha channel
- Working with video in Photoshop
- Using Photoshop documents in video editing applications
- Working with adjustment layers, text, and layer styles
- Color grading controls in Photoshop
- Using Vanishing Point and Photomerge