Have you ever printed a picture from the Internet and found that it looked blurry or “blocky”? The culprit is usually the image resolution.
Image resolution differs from printer resolution, and it’s essential to understand the difference between them. This article will explain the basics of image resolution and how to determine the best print resolution for your images.
What Is PPI?
The PPI of an image is the number of pixels per inch in a digital image. It is an important measurement when preparing an image for printing because it affects the final quality of the print. Higher PPI values mean an idea will have sharper details and a crisp appearance.
Regarding print resolution, PPI works alongside DPI (dots per inch). In general, higher DPI values produce better quality prints, but this is not always the case, and other factors, such as color accuracy and viewing angles, play a role in overall print quality.
You can usually find the PPI of an image by right-clicking it and selecting Properties. Windows users can also open an image in their Finder app and find the information under the Details tab. In some cases, Photoshop may need to perform a unique process called resampling when changing an image’s PPI. This process involves creating or deleting pixels to preserve image quality.
You should avoid changing the PPI of an image you plan to print. Resampling can produce unintended results such as jagged edges or other artifacts. The best option is to create new ideas at the desired or best resolution for printing rather than resizing existing ones. Raster programs such as Photoshop set the PPI resolution of a new document at its creation, and you will generally see it listed with other parameters in the New Document window.
PPI vs. DPI
Some people use PPI and DPI interchangeably, but the concepts differ. PPI defines the resolution of digital images, whereas DPI describes the physical number of ink dots in a printed image. The difference between these two measurements can significantly impact the quality of an image.
For example, choose a higher PPI to ensure the image is sharp and straightforward if you want to print a photo. On the other hand, you can use a lower PPI for web images since monitors typically have a high enough pixel density to display high-resolution images.
In contrast, you may notice that images downloaded from websites or a quick Google search are often fuzzy and pixelated. This is because they are saved at a very low PPI to save file size and speed up website loading times.
DPI is also important for print because it determines how an image will be reproduced. Printers produce images by spitting out tiny dots of ink on the paper, and the more of these dots there are per inch, the better the image quality will be. It would be best to have a large printer with ink and specialized printing equipment to achieve a high DPI. This is why many professional print services recommend using 300 DPI when preparing digital files for printing.
PPI vs. CMYK
As you zoom in on any digital image, it breaks up into colored squares or pixels. These are the minor elements that make up the entire picture. Knowing PPI for digital and print displays is essential because it tells you how many pixels are packed into an inch of space. If you double the PPI, you get quadruple the number of pixels in that area, meaning the image will be much sharper.
When it comes to printing, the recommended PPI is slightly different. This is because of the way that printers render graphics. While digital media uses a base of RGB colors, print jobs use CMYK, which comprises cyan, magenta, yellow, and black dots. To accommodate these dot-based colors, printers need to be able to print high-resolution images to produce precise, crisp results.
The industry standard for print is 300 PPI. However, higher PPI can sometimes be beneficial, especially when an image is scanned and used for a large printed document or mural. This can reduce the amount of ink needed, which can help cut costs and reduce the time it takes for the printer to complete a job.
While keeping track of all the different units related to resolution can be confusing, it’s essential to understand PPI and DPI for both digital display and print purposes. This will ensure that your designs are as high quality as possible and can be viewed by the broadest audience.
PPI vs. RGB
PPI is a digital measurement of pixels, the smallest addressable element in a raster image. Pixels are part of the RGB (red, green, blue) color space and are the building blocks of digital images.
In contrast, DPI refers to the number of ink dots a printer can deposit on paper per inch. When working with printers, understanding DPI is essential for ensuring your designs look crisp and sharp when printed.
When printing an image at 300 PPI, the tiny dots can combine to produce a full range of colors that look like the original photo when viewed up close. But, if you step back from the print, you’ll see that it looks pixelated.
Because printers use the CMYK (cyan, magenta, yellow, and key/black) subtractive color model to create images, they only have 3 or 4 possible ink dot combinations for each pixel. Hence, they can’t reproduce all 65+ thousand colors the human eye can perceive.
Luckily, some programs can work around this limitation and change an image’s pixel density without losing quality. This process is called resampling and is very common with image editing software.
