Subtitles of the Movie

More about image size: I want to talk about some of the basics of resolution. Generally, you can divide the world into two types of resolutions. One for screen resolution, and that would be for the World Wide Web. There's a very popular need for this as well as if you were designing images for television or video production, it's generally quite low resolution. And the general resolution needs for say for World Wide Web is 72 pixels per inch. Now that's very different for print resolution. Print resolution needs much more data to resolve, because it can resolve much finer detail. The general rule of thumb for print resolution is to multiply times two the line frequency of your line screen. So two times the screen frequency, and generally for magazines that is about a 150 lines per inch yielding a 300 pixel per inch image. Or image need I should say. Now things like newspapers have a much lower line frequency, so you don't need that high resolution. And some really high res sharp fine art print books have an even higher line frequency, so you would need a higher digital image resolution. But generally if you are designing images for a magazine, 300 pixels per inch is pretty good. I want to go back to my original cow image here and go to the image menu>image size and talk about this. Notice that this image is 300 pixels per inch, so if I were going to submit this picture for reproducing in a magazine, it would reproduce well at about 5x4 inches because there is enough pixel information at 300 pixels per inch. And at this size it yields 5-1/2 megabyte file image. So I'm going to hit cancel for now. I'm going to duplicate this image. And I am going to design it for the World Wide Web. So I'm going to go ahead and say duplicate, go back to image>image size. And now I am going to throw out pixels, because I am going to go now into the resolution section here and type in 72 pixels per inch. And notice when I do that, what it does is it says - well! If I'm going to keep the width and height the same, and that is indicated by this little lock icon here that the width and height ratio is the same but I am throwing out a lot of pixels per inch. Down resing or interpolating down as it's also known, throwing out pixels. So at the top of my image size dialogue box it's giving me what will be my new file size, 324K ,from what was my old file size: 5-1/2 megabytes. So I'll go ahead and say ok. And you can see that my image has gotten much smaller at the same zoom ratio. I'm going to go ahead and zoom up a bit. So there is my image at a 100% zoom designed for the World Wide Web. That would be a very large image, 5 and 1/3 by 4 inches, for the World Wide Web. So that is some basics for image size and resolution. It's just very important to remember that your image is really a collection of square pixels on this grid. And if we zoom in, we can see in this low-resolution image the actual pixels which make up the image. And it stands to reason that the more pixels that you pack into a given area, say a square inch, the larger your file size. So it's important to understand this basic concept of pixels per inch relating to file size. And in the next few lessons, we are going to talk about how these also relate to the zoom ratio.