From the course: Learning Print Production: Photoshop, Illustrator, and InDesign

Image resolution

- [Instructor] When you're working with images, you have to keep in mind that an image only has a certain amount of information in it and you can't make something out of nothing. Well, why does that mean anything? Look at this image, it looks pretty sharp. If I go up to image and image size, I find out that it's a little over four inches wide, three and three-quarters inches tall and it's 300 pixels per inch. If I place this image into InDesign or illustrator at a hundred percent, at the same size, it should print perfectly fine. We tell you as a guideline that your images should be at least 250, and aim for 300 pixels per inch at final size for successful printing. But what happens if you have a very small image and you need to scale it up, or you have an image that's low resolution? Well, I'll go back and repeat, you can't make something out of nothing. And let me give you an example. I have a low-resolution version of this image. And when I switch, I think you already see some loss of detail. Let's check its resolution and size. I'll go to image and image size again. It's the same dimensions but it's only 72 pixels per inch. Given that I said, we'd like for an image to be 300 pixels per inch, you might think, "Well, I'll just change the resolution to 300." Well, let's see how well that works out. I'll just highlight the resolution, change it to 300. by the way, if you're going to have to scale something, let Photoshop do the heavy lifting for you. Just check automatic, that's the default and it'll do the best it can. Then I click okay, and I'm going to hit control-zero or command-zero on the Mac. It looks pretty good, but let's compare it to the original 300 pixel per inch image. I'll go to window, arrange, and two-up vertical. The 300 pixel per inch image is on the right, and of course the resed-up version is on the left, and I think you can see great loss of detail. The truth is, there wasn't that detail in the low resolution image. Photoshop was trying to guess as it filled in the blanks. So what does this mean for you? Ideally, have an image of 300 pixels per inch at the final size you're going to use it in InDesign or illustrator. If your client gives you something that's not that nice, it's low-resolution or it's small, and you're going to have to scale it up or res it up, do that in Photoshop. Photoshop will try. It's never going to be perfect but you'll get a better result if you scale up in Photoshop than if you scale up in, say, InDesign or illustrator. And if you're faced with this circumstance, let me make a suggestion. Early on in the game, when you find out that this is all your client's going to give you, show them an example like this on screen, so that they understand that you can't really make something out of nothing, that you're going to try, and give them an idea of what the result is going to be. You may find that they magically come up with a high-resolution image, or maybe they'll accept you using that image at a final size that's a little bit smaller. The game is really trying to make the client happy without driving you crazy, and letting Photoshop help you as much as it can.

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