Join Chad Perkins for an in-depth discussion in this video Understanding resolution, part of Learning Photoshop CS6.
Once you understand the fundamental concept of pixels, then you're ready to move on and look at the equally fundamental concept of resolution. So here in Photoshop, I have my image, and I'm going to go to the Image menu at the top. And I'm going to Choose Image Size. So again, the Image menu > Image Size. This is a very important little area of the program. Here's, what, in a nutshell what's going on here. Photoshop is giving us the basic information about our image, and also allowing us to make some changes.
So we can see here in pixels what our image is. It's 861 pixels wide, and 628 pixels high. We also see the document size in width and height in terms of inches, and the key here is resolution, that's the magic number here. And basically what resolution means, is how tiny pixels are or more specifically how many pixels can you fit in an inch? Now the default for all screen displays if your going to go out to a mobile device or a TV screen website the default resolution you want to use is 72 pixels per inch.
Now this is not sufficient if you were going to print. For print you would want a resolution of 300 pixels per inch. So when we look at this image it says by default that the width is about 12 inches and the height is about nine inches almost, eight and a half we'll say. And so we might say great that's a big size. But if we were to print this, it would look terrible because the resolution is only 72 pixels per inch. The squares, the little squares here, the pixels that make up this image would be far too big and it would just look terrible.
So we could then take the resolution to 300 pixels per inch. That's great, right? It made our width and our height get way bigger. And now we can print it, correct? Well not really, and the reason why that won't really work is because Photoshop would be stretching this and adding more pixels in. But it's not going to be clear and sharp as it would have been had you had it at its original size so, it would be like blowing it up. It would definitely get softer and lose some of its clarity. So, I'm going to take the resolution back to 72 pixels per inch. What I'm going to do is uncheck Resample image.
Resample image gives Photoshop permission to scale up or scale down your image and we don't want to do that. So I'm going to keep my resolution, or actually I'm going to change it to 300, but making sure that resample image is unchecked. So when we do that, because Photoshop does not permission to resize our image, it's just changing the resolution, it changes the inches so that actually the width, the true width and height for this image if we were going to print is only a meager 2.87 inches by two inches. So if we were going to print this image, this is the best we could get it to look or this is the biggest we could get the image to print and still look good. Now I'm actually going to reset this dialog box. I want to basically clear out all my settings.
I have kind of fill with a lot of stuff here. I don't actually have to close this and open it back up again, if I hold the Option key on the Mac or the Alt key on the PC, we get a little magic secret here. Watch the Cancel button. If I hold the Option key, or the Alt key on the PC, it turns into a Reset button. So I'm going to go ahead and click Reset, Reset all of my settings here. And one other thing that I wanted to show you that I use all the time, is, right here where it says inches. These are basically units of measurements. We have points and picas and centimeters and stuff.
But a real cool one is percent. So often times what I'll say is well, I actually want this image to be half-size, I might want to put a version of it on the web, and so maybe I'll make this 50%, Resample the image and now my image is a much smaller 431 pixels by 310 pixels. So, that's another thing that you can use, and then once you're ready, you can go ahead and click OK, and we'll notice that Photoshop then shrinks our image to half of the size. Understanding image resolution, especially as it pertains to print resolution, can be a tricky subject. But it's really important that you are aware of that dialog box, so that if you are to print, or even if you are to save for the web you don't have any sudden changes that kind of throw you for a loop.
- Getting images into Photoshop
- Creating and navigating documents
- Working with layers
- Cropping and straightening images
- Color correction
- Making selections
- Fixing image problems
- Working with effects
- Creating and editing text
- Exporting and printing