How to Check DPI

Have you ever heard of DPI? If you haven’t, DPI stands for “dots per inch” and refers to the resolution of an image. Regarding book printing, DPI is used for printer resolution and will indicate the clarity and detail of an image when printed on paper. So, 300 DPI means that every inch of an image contains 300 dots of ink. Plus, the higher the DPI, the better the quality of the image because there will be more ink droplets tightly grouped. Understanding what it is and how to check DPI is important if you want to print images inside your self-published book.

Keep reading to learn how to check the DPI of digital photos on a Mac or Windows, why 300 DPI is important if you’re self-publishing a book, and where to get help scanning in physical photos if you need digital copies made.

How to Check DPI of a Photo on a Mac Computer

1. Click on the “Finder” app and locate the image you want to check DPI on.
2. Right-click your mouse on the image file and choose “Open With” which will open up another pop-out menu and you will select “Preview.” This means you’re going to open the image file in the Preview app.
3. Once the image opens in Preview, go to the top toolbar, and click on “Tools.”
4. Then click on “Show Inspector.”
5. In the screen that opens, you will choose “General Info.” It should be the first tab that appears at the top of the screen that opened.

How to Check DPI of a Photo on Windows

1. Open “File Explorer” and find the image you want to check DPI on.
2. Right-click your mouse on the image file you want and choose “Properties.”
3. Then go to the “Details” tab at the top of the bar and click it.
4. Finally, you will scroll down until you see the image “Dimensions” and “DPI resolution.”

Changing the DPI of a Photo

If you find that your photo has a low DPI, you may consider changing it to a higher resolution. Keep in mind, however, that for any photo that starts at a DPI that is less than 300 and you use the directions below to increase your photo’s DPI to 300, the photo may not print at the highest quality, or it may print very small. So, it’s always best to start with a photo that is 300 DPI or higher.

How to Change the DPI of a Photo on a Mac

Follow the instructions below if you want to change the DPI of a photo on a Mac computer.

1. Click on the “Finder” app and find the image you want to check DPI on.
2. Right-click your mouse on the image file and choose “Open With” which will open up another pop-out menu and you will select “Preview.” This means you’re going to open the image file in the Preview app.
3. Once the image opens in Preview, go to the top toolbar, and click on “Tools.”
4. Then click on “Adjust Size.” You’ll see the width, height, and resolution of your image.
5. Next, uncheck the box for “Resample Image.”
6. You will type “300” into the “Resolution” section. This automatically adjusts the width and height of your image to the proportions your image can be printed at to achieve a DPI of 300.
7. Next, you will click on “OK.”
8. For the last step, you will go to “File” in the top menu bar and click on “Save.”

How to Change the DPI of a Photo Using Windows

If you used the steps in How to Check the DPI of a Photo on Windows (above) and found that your photo’s resolution is less than 300, you may be wondering how you can change the DPI of your photo. Unfortunately, Windows computers do not provide users the ability to change the DPI of photos using native software.

How to Set the DPI On Scanned Photos

If you are writing a memoir, a legacy book for your family, or your testimonial story, you may decide to include old photos in your printed book. Some of your images may be old enough that you don’t already have digital versions of them. So, if you are going to include these physical prints of photos within your book, you’ll need to scan them to your computer at 300 DPI to create a digital copy of the photo.

If you have a tech-savvy family member or friend, ask them for help scanning your photos. You can also visit Office Depot for help with scanning your images at the correct DPI for a small fee.

Scanning in photos at 300 DPI, however, may not work for faded physical photos or Polaroid-film photos. Even with the right DPI, scanning in old photos won’t improve or fix them.

If you are publishing your book with Xulon Press, we recommend speaking with our Pre-Production support team to ensure that you can correctly submit your digital images.

Why is DPI Important for Self-Publishing?

Now, you may be wondering why a 300 DPI is important for printing images inside of your self-published book. When including images in books, it’s important to use 300 DPI to ensure the images are of the highest quality when the book is printed and available for sale. Submitting images for your book that have a lower DPI may result in blurry or pixelated images.

As a Xulon Press author, we recommend scheduling a virtual appointment with your Author Representative once you’ve purchased a publishing package. This appointment sets you up for a successful publishing journey. If you’re not part of the Xulon Press author family yet, call 1-866-381-2665 to get started today!