Way back in September, I wrote an article about The Power of a Print. I talked a bit about many of the things we do with our images these days– from editing and processing to sharing and blogging. What we hardly every do anymore, I pointed out, is actually print them. I’m not talking about the work we do for our clients. They’ve hired us to create those images, at least some of which almost always get printed. When it comes to the images we capture for ourselves, however, printing hardly ever seems to be at the top of our priority list. How many truly stunning images are living inside your computer, external hard drives, or even your phone? What sort of joy or sense of accomplishment are they bringing you from the deep, dark depths of their binary existence? I’m not going to rehash that whole post here (although I do encourage you to read it), nor am I here to lament the terabytes of unprinted pixels in the world. I received an email from a reader the other day asking me if I could clarify a few points for him on how to resize images for print. Rather than just dash off a quick reply, I decided to address it here.
Let me start by saying these methods are demonstrated in Photoshop, as opposed to Lightroom, because that’s my workflow. Any image that’s going to print takes its last steps in Photoshop. That’s not to say that other methods are wrong– just different. Having said that, though, the processes in Photoshop and Lightroom are very similar. Also, we will be talking about JPEG files. Even photographers who shoot raw eventually convert their images to JPEG before printing, as do professional print labs. Although it should go without saying, I’m going to say it anyway– Do not make any of these changes to your original image file. Always, always, always work on a copy.
Aspect Ratio– The Elephant in the Room
If you were to try printing images straight off your camera, chances are good that you’d have no problem printing 4×6 or 8×12 with only very minor adjustments. The frames of the world come in a wide variety of other sizes, though, so knowing how to best resize those native size/resolution images to 5×7, 8×10, 11×14, etc., is a pretty important skill. For the sake of this article, we’ll be using this butterfly image I took a few years ago. As you can see in the Image Size dialog box (Image > Image Size…) the original dimensions of the image are 4288 x 2848 pixels (14.293 x 9.494 inches) at 300 pixels per inch (PPI). These values give us plenty to work with, but they’re going to need some help if we want to print an 8×10.
Photoshop’s default convention is to retain the aspect ratio of the original image. See that bracket and link icon next to the pixel measurements? This means that the measurements are linked together. Whenever the “Constrain Proportions” box is checked, changing one value will automatically change the other in order to keep the original aspect ratio. This helps avoid situations that might result in a distorted image. If we’re going to do this right, we have to find a way to do it without stretching or twisting the original.
This first method is basically a two-step process that begins with the crop tool and ends with the image size dialog. Adobe gave the crop tool a major overhaul with Photoshop CS6. For a full breakdown, check out this great video tutorial. In any event, the crop tool has been designed to crop based on preset aspect ratios or user-input sizes. For our two-step process we’re going to stick with aspect ratio crops. You give Photoshop its starting point by selecting “Original Ratio” from the drop-down menu at the top of the screen. For our 8×10, I’m going to enter 10 and 8 into the empty fields to the right of the menu. Don’t worry about including units of measurement in those boxes. Photoshop knows that you’ve selected to crop to aspect ratio, rather than size.
You can now drag the crop box around your image. You should notice that the proportions remain fixed, regardless of how much larger or smaller you stretch the box. Once you have your image properly composed within the box, you can commit the crop by hitting the Enter/Return key, or clicking the check mark at the top of the screen.
If we return to the image size dialog box after the aspect ratio crop, we discover that our image measurements have changed, but they still don’t measure out to 8×10. Remember what happened before when we tried changing one value? It also changed the other value and neither worked for our purposes. Now, however, if we change the long side of our document size to 10, it automatically changes the short side to 8, giving us the 8×10 we want.
What is Resampling?
Another important element of the Image Size dialog box is the “resampling” check box near the bottom of the window. In order to understand what it does, we first have to understand what Photoshop is doing when we make an image larger or smaller than the original. When we tell Photoshop to make an image smaller, it is essentially throwing out the extra pixels we no longer need. When we tell Photoshop that we want to go bigger, though, it has to add pixels and is basically guessing. Resampling allows Photoshop to make a more educated guess about those extra pixels.
Our second process uses the crop tool only. By selecting “Size & Resolution” from the drop-down menu, I can enter the exact values for my desired print size and resolution. We’ll address resolution in a minute, but for now let’s stick to the crop. I usually go with this second method when I’m cropping out large portions of my image. Plus, it’s just quicker. It’s important to realize, though, that different methods of resizing are going to affect the overall image file in different ways. When resizing with the crop tool, for instance, the pixel dimensions and file size change, but the image is not resampled. Pixel dimensions and resolution incorporate more pixels per inch based on the size of the crop region, but Photoshop is not specifically adding or subtracting data from the image. This is why two 8×10’s of the same image– one from each method– can result in different overall file sizes.
Technically, this method is neither a resize nor a crop. If you find yourself with an image that only needs a very minor tweak or two, you can always create a new document in Photoshop in the precise dimensions of your choosing. You can then drag and drop your original image onto the new document. CTRL/CMD+T will reveal the bounding box and you can then adjust your original image to its new size. Flatten the image when you’re done (Layer > Flatten Image) and save as a new image. This method originated with earlier versions of Photoshop, before some of the other tools became as sophisticated as they are today. It’s still tried and true, though, and yields good results.
A Few Thoughts on Resolution
Conventional wisdom used to dictate that “high resolution” images be printed at at least 300 ppi. I often still do, but only out of force of habit. Most printing experts will now tell you that anything above 240 is extraneous and only serves the purpose of creating larger image files. I don’t bring this up in order for us to debate the issue in the comments. I bring it up because you may occasionally notice the resolution changing when making adjustments in the image size dialog. As long as you are right around 240, you’re fine. Some say you can go as low as 200, but I never go below 240. It’s also worth pointing out here that Lightroom’s default print resolution is 240.
The beauty of Photoshop is that there are almost always several different ways of completing the same task. Personal preference, ease of use, and force of habit are the main factors in my own decisions of how to do what I need to do with any given image. Figure out what works best for you, but don’t forget you have options. Different photos may need different approaches.
If you found this helpful, also be sure to check out another one of our recent articles, 12 Essential Photoshop Skills Every Photographer Should Know.
Images are Copyright Guyer Photography. All rights reserved.