Subtitles of the Movie

I want to cover basic concept in Photoshop and for that matter in all the imaging applications, and that is the basic concept of your image size. And we'll run into this in various areas of Photoshop over and over again. So it's helpful to understand the basics of image size. Image size in my mind is a combination of an image's actual width and height information, usually measured in standard units such as inches or centimeters, times its pixels per inch resolution. So that will give me my image size. And very often what I'm more interested in is a pixel count, how many pixels across and how many pixels down. Because that is ultimately all I really get in a digital raster based image, is a set of pixels. Of course a raster-based image is a grid of pixels, so you have so many pixels across by so many pixels down. Pixels per inch is also known as PPI, the shortened version of pixels per inch. And that is also known as an image's resolution. So I want to talk about some of these key phrases such as resolution and pixels per inch, file size, pixel count and interpolation. I'm going to go to my file browser here and talk about one of the features of my file browser. And with my pictures of the cows currently selected, notice that one of the pieces of information here is the actual pixel count - 1600 pixels across by 1200 pixels tall. And I can even see that it is giving me a particular file size, meaning that this seems to be a very high resolution. So I'm going to go back to my document, and go back to the document that this is actually based on. So, I'm going to go to window menu> documents, and choose this document. And I'm going to duplicate this document under the image menu>duplicate. Just say go ahead and do that. Now what I'm going to do is resize this document using image size. And I'll talk this in more detail in a later movie, but right now this is just to get across the point about file size. What I want to point out here is, notice that this image looks to be about the same as this image in the background. But there is an important distinction. And you have to become a little bit more familiar with Photoshop to appreciate this. And that is look at this zoom value here - 100% zoomed in versus 33% zoomed in. That means that this image is showing me a one-image pixel for one-screen pixel. Remember that my computer monitor is a type of output device and it is actually quite low resolution. The computer monitors generally resolve at about 72 pixels per inch, and that is the basic standard resolution for web design. Of course, because your web content is usually designed to be viewed on a computer monitor. This image originally opened up is 3 times as large and I see that because the zoom ratio is 33%, so that means that I can still zoom in to 100% and it will be much larger. So there is 100% zoomed in, 1 image pixel for 1 screen pixel. And if we do that to this other image, notice what happens here. My image looks very pixilated, because we are now looking at 1 image pixel for every 3 screen pixels. So we can see that this is of course how an image is actually made. It's a collection of individual discreet pixels on a grid. You will come across dealing with image size and resolution in various areas. Particularly when you go to file menu>new, it will ask you to make some decisions there. Or if we went and do something like I did such as change the actual image size under image menu>image size. It will bring up this dialogue box. Which is essentially a calculator. And in the next few lessons, we are going to talk about how you can manipulate image size. Before we go, I do want to make a one point and that is also notice when I zoom back out and make these images look be about the same visual size on my monitor, not only is the zoom ratio different here, I'm zoomed out to 50%, here I'm zoomed out to 16.7% I am going to make this a little bit larger so we can see more information about these pictures. And what I want to point out here is that even though we are looking out at images which look visually the same size, my document window is also giving me another indicator that this image is 5 & 1/2 megabytes in size, this image is 0.6 megabytes in size - much smaller. So right there I know that there is much less information in this image than there is in this image.