Everything you need to know about image resolution.
Image resolution definition.
In digital photography, resolution is the level of detail contained in an image. More specifically, it refers to the number of pixels that exist within that image. The higher the resolution, and the richer the pixel count, the more detail and definition you will see.
How is resolution measured?
The resolution of a digital image is measured using its pixels; specifically in pixels per inch (PPI). For printing, picture resolution is measured by dots per inch (DPI), referring to the tiny droplets of ink that printers create.
The higher the image resolution, the more pixels are bunched together — which creates a smoother, more detailed image.
The phrase ‘high-resolution’ is often used synonymously with quality — as vivid, crisp images are what we typically associate with good photography. However, it’s important to remember that resolution is just one factor that can affect image quality.
The term resolution is also used across several other industries to determine the detail of an asset, including:
Picture resolution example.
Take a look at the example below to see the difference between a high-resolution image, and a low-resolution image.
The difference between the two macro images of ripe raspberries is clear. The high-resolution image (top) is 4715 x 2779px, with a resolution of 300 DPI.
Meanwhile, the low-resolution image (below) is 200 x 118px, with a resolution of 96 DPI.
As the pixel dimensions of the low-resolution image are significantly smaller than the higher-resolution one, when enlarged this makes the image pixelated.
The more pixels in an image, the larger it can be without degrading.
How do I find out what my image resolution is?
It’s easy to find the image resolution of your photo or digital asset using Adobe Photoshop.
Play around with its tools to find the right measurements for your project.
Launch Adobe Photoshop and open your image.
From the top bar, select Image > Image Size.
Here, you can find out the resolution in PPI.
How to find out image resolution on Windows.
You can also find and view the image resolution of your photos on Windows. However, unlike Photoshop, the information for these values can be more restrictive.
On your computer, navigate to your image file.
Right-click on the image and select Properties from the list of actions.
In the Properties box, find and click the Details tab at the top.
Look for the Dimensions, Horizontal Resolution and Vertical Resolution values to find your image resolution in DPI (for example, 300 DPI).
How to find out image resolution on Mac.
Finding your image resolution is simple on a Mac.
Find your image file and right-click or control-click it.
Hover over Open With and select the Preview app.
At the top, select Tools and find the option for Adjust Size.
View the image dimensions, including Width, Height and Resolution in PPI.
Finding the resolution of an image is straightforward when you use professional editing software. Adobe Photoshop, Lightroom and InDesign all offer effective tools for resizing and editing digital assets, ready for printing or online use.
What resolution size do I want?
What resolution size you need can vary depending on the project. There are various factors that can determine the ideal photo resolution.
To start with, consider the purpose of your image, how large it needs to be and where it will be used. Here are a few examples to get you thinking:
If so, then using a high picture resolution of 300 DPI may be the best way to print and display them. This value can be tweaked depending on the level of detail required, how far away the viewer will be and how large the image needs to be.
For certain projects, such as large prints, you may be able to use 150 DPI. When viewed from a distance, the difference isn’t overly noticeable to the human eye.
On the flip side, if the final purpose of the image is as a tiny thumbnail, you can usually get away with a lower resolution size.
Online vs offline
Generally, images used online don’t need to be as substantial in resolution as offline or printed images.
So, if you are putting together a personal blog or updating a client’s site, your eye-catching imagery can often be as little as 72 PPI when uploading them to the web.
Ease of storage
Storage is another important consideration when working with large numbers of images. How much storage do you have? Is it better to use smaller images that are easier to store on a server or computer – or on the cloud?
After all, detail comes at a cost. The more pixels an image has, the higher the resolution, meaning a larger file size.
But don’t worry. After you’ve perfected your picture to the right specifications, there are ways to help reduce file size by compressing the image, without sacrificing on quality.
When working with digital assets, you might also need to consider the right resolution for printing. The last thing you need is to spend hours on an asset, only to be disappointed when it comes back blurry and unprofessional after being printed!
Even though images can look great on a screen at 72 PPI, you’ll need to print your images at a minimum of 300 DPI to ensure the best results. If you’re producing work for a client, it’s always a good idea to confirm what their preferred picture resolution is for the final product, so you don’t get any nasty surprises.
The kind of paper you use can also make a significant difference to quality, as different types of paper will absorb ink differently. So, whether it’s a glossy magazine, a poster or a business document, make sure you use the right paper for the job.