Photoshop tutorial: Understanding resolution | lynda.com

Photoshop tutorial: Understanding resolution | lynda.com

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20]When it comes to video graphics, a lot of folks get confused in the area of resolution.

[00:00:05.

40]You'll hear the term PPI or DPI thrown out there.

[00:00:09.

02]DPI is, "Dots Per Inch" and that's really a printing term.

[00:00:12.

93]PPI is, "Pixels Per Inch" and that's much more relevant when discussing computer graphics.

[00:00:18.

40]However, in terms of video, none of it is relevant.

[00:00:21.

68]You see, the same size video graphic can be displayed on multiple sizes of screens.

[00:00:26.

96]So, I could take that 720p graphic or video file and put it on a television set [00:00:32.

47]that's huge in my living room.

[00:00:34.

46]Put it on an iPad and look at it on that screen.

[00:00:36.

95]Shrink it down to a mobile phone on the Android operating system or even play it [00:00:41.

44]back in a movie theater.

[00:00:43.

15]You see, it's the same number of pixels.

[00:00:46.

22]When dealing with video, you have fixed resolution formats.

[00:00:49.

83]Meaning that, we measure them in total pixel count.

[00:00:53.

41]Let's take a look at some files and see how this really comes to life.

[00:00:57.

52]In this particular image here, I have a lot of pixels to work with, more than I [00:01:01.

68]need for a video file.

[00:01:02.

93]If choose Image, Image size, I could see the pixel count and it's right now 1343×895.

[00:01:09.

91]Now, that's too low for use in 1080p, but more than enough, for using the 720p [00:01:15.

29]HD format and plenty for standard definition work flows as well.

[00:01:20.

34]Let's zoom in here.

[00:01:21.

87]This particular image is a Mosaic, meaning that small tiles make a larger image.

[00:01:28.

00]If you look closely there, you could see a sort of the silhouette of a dog as [00:01:31.

90]well as a busy field.

[00:01:33.

70]Let's start to zoom in and you notice here, that's a 100% and as we keep going [00:01:38.

85]in, the image will start to be pixelate.

[00:01:40.

79]That's because these individual areas are really squares of light.

[00:01:46.

20]The white lines show you the border on each pixel.

[00:01:50.

28]Now, I could bring up the Navigator Panel and this makes it easier to see the [00:01:53.

97]whole image and notice by dragging, I could zoom in or out and use this red box [00:02:00.

03]to move around the image.

[00:02:02.

09]Each square is one pixel value.

[00:02:05.

75]If you take the Eyedropper tool and you click, you'll see that the colors update [00:02:10.

62]over in the color mixer, so you can actually see what that square is doing.

[00:02:15.

61]However, when put together, those individual pixels comprise an image and asyou [00:02:20.

82]zoom out, it starts to take shape.

[00:02:23.

34]This is a pretty straightforward concept, but what I'd like to show you is how [00:02:27.

05]it works with the same image sized for different workflows.

[00:02:31.

28]Let's switch over to Adobe Bridge and I have the same image prepped for both [00:02:36.

07]standard definition and HD.

[00:02:38.

73]You'll notice here that we have the 720p version.

[00:02:43.

11]Let's adjust this here, 1280×720, here's the HD1 1920×1080, the two common [00:02:52.

89]HD sizes and then we have the standard definition, in this case, 720×480 and 720×480.

[00:03:01.

82]However, they display differently.

[00:03:03.

51]This is because of pixel aspect ratio, which is a topic, we'll explore more [00:03:07.

61]in an upcoming movie.

[00:03:09.

05]But essentially, it means that pixels are not square or a one-to-one ratio.

[00:03:14.

04]Therefore, the numbers may not actually represent how the image displays.

[00:03:18.

41]While both of these images are 720×480, they will display in size differently on the screen.

[00:03:25.

68]Let's go ahead and open these up and I'll press CTRL+R for the rulers and [00:03:31.

52]right-click and switch to pixels.

[00:03:33.

72]So, this one is 720×480 and this one is also 720×480.

[00:03:40.

11]However, one is a 4×3 aspect ratio and the other is 16×9.

[00:03:46.

59]Both of these graphics could work in a DVD slideshow.

[00:03:49.

46]The 16×9 aspect ratio is more commonly used these days, even when dealing with [00:03:54.

03]standard definition video for a DVD.

[00:03:56.

62]For the 1080 graphic, you'll notice here that it's 1920×1080 and the 720 [00:04:01.

50]graphic is 1280×720.

[00:04:05.

08]You can always check this by going Image, Image Size and it will bring up the dialogbox.

[00:04:11.

35]What I want you to realize is that resolution does not matter.

[00:04:15.

03]So, if I uncheck the Resample Image box and Ichange the Resolution per inch.

Let's say to 200.

[00:04:22.

48]You'll notice that the print size would change, but the total pixel dimensions [00:04:26.

81]has not changed, meaning that the file still has the same display size.

[00:04:33.

06] [00:04:33.

51]So, changing the resolution field, that describes the pixels per inch, will have [00:04:37.

58]no impact on the video because video graphics are measured in total pixels.

[00:04:43.

22]Again, 1920×1080, for the HD version here, changing the resolution has no impact [00:04:52.

23]on the width or height, when we uncheck "resample image".

[00:04:57.

06]Clicking OK, you'll notice that the document does not change sizes.

[00:05:01.

41]A nice shortcut is to Alt or Option click down here, and you can [00:05:05.

10]quickly check the specs for a file, seeing the width and height, as well as the [00:05:09.

76]channel information, which we'll talk about in the second and the resolution [00:05:13.

67]setting, which can be ignored for video graphics.

[00:05:17.

35].

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