Print resolution and screen (or source file) resolution refer to two different concepts related to the quality and clarity of images, but they are often confused due to their similarities. Let’s delve into each term and their differences:
Print resolution refers to the number of dots or pixels per inch (DPI or PPI) that an image contains when it is printed on a physical medium, such as paper. It is a critical factor in determining the sharpness and clarity of printed images. A higher print resolution results in finer details and smoother gradients in the printed output. Printers use dots of ink or toner to recreate an image, and higher resolution images can represent these dots more accurately.
For example, a standard quality print might use a resolution of 300 DPI, meaning there are 300 dots or pixels per inch. This is a common standard for producing high-quality printed materials like brochures, magazines, and posters. If you were to print a low-resolution image with fewer dots per inch, it might appear pixelated or blurry.
Screen or Source File Resolution
Screen resolution, also known as source file resolution, refers to the dimensions of an image as displayed on a digital screen, such as a computer monitor, smartphone, or tablet. It is typically measured in pixels. Screen resolution determines the clarity and quality of an image as it is displayed digitally.
Common screen resolutions include 1920×1080 (Full HD), 2560×1440 (Quad HD), and 3840×2160 (4K Ultra HD). The higher the resolution, the more detail can be displayed on the screen. However, screen resolution doesn’t directly translate to print quality. An image that looks crisp and clear on a high-resolution screen might not necessarily translate well to a high-quality print if its resolution is inadequate.
- Print Resolution: Expressed in DPI (dots per inch) or PPI (pixels per inch).
- Screen Resolution: Expressed in pixels (width x height).
Purpose and Output
- Print Resolution: Primarily concerned with the quality of printed materials.
- Screen Resolution: Pertains to the quality of digital display on screens.
- Print Resolution: Higher DPI/PPI indicates finer detail in printed output.
- Screen Resolution: Higher resolution screens show more detail on digital displays.
Scaling and Display
- Print Resolution: Not affected by screen size; the same image will have the same print resolution on different paper sizes.
- Screen Resolution: Varies with screen size; the same image will have different screen resolutions on screens of different sizes.
What is good resolution for printing?
This can depend on the printer used for printing. In the early days of laser printers, a common print resolution was 300 dpi which is a great resolution for typical 8.5 x 11 standard document laser printing. 300 dpi is the most common print resolution in consumer black and white and color laser printers, with some higher quality and more expensive laser document printers printing up to 1200 dpi. High quality home and prosumer inkjet printers typically print at 1200 dpi. Posterprintshop uses the highest quality commercial inkjet printers available from Epson and Roland which print at 2400 dpi for extremely high photographic quality prints. You can learn more about the printers Posterprintshop uses and our commitment to quality here. At 2400 dpi, it’s impossible to see the actual dots making up the print with the naked eye.
What source file resolution is needed for high quality printing?
This can be a confusing question for many when you try to apply print resolution (300 dpi, 1200 dpi, 2400 dpi) to screen or source file resolution. DPI is irrelevant when discussing source file resolution, instead what is important to focus on is the overall pixel measurements in each dimension. This is a measurement of how many pixels across (width) by how many pixels down (height) are in the source file. A 1024 px by 800 px file is rather small and doesn’t have enough pixels to be enlarged to a huge poster without getting blurry at larger sizes. A 2700 x 3600 pixel file size has enough pixels to look photo quality when we enlarge it to a 36 x 48 poster.
A general rule of thumb is that the more pixels (x by x) in your source file, the larger you can print without losing quality. Always try to get the highest resolution source file possible for large format printing. We have a great guide to file preparation and typical image sizes and the suggested source file resolutions in our HELP – File Preparation article.
Finally, a common misconception for customers trying large format printing for the first time is the thought that you need to match source file resolution to the printer resolution (thinking that you need a 2400 dpi source file for our 2400 dpi printer resolution). This is impossible to achieve when you understand everything explained above. With this thought process, a 2400 dpi source file would be 2400 x 2400 just to print a 1″ inch by 1″ print. By the time you create a 2400 dpi source file for a 36 x 48 poster, you’d have a 86400 x 115,200 source file which is not only too large for most software to handle, but probably too large to upload quickly. All of those pixels in the source file are overkill and not needed. Why? As we’ve explained above, source file (screen resolution) and print resolution are two different things. The same 2700 x 3600 pixel file could be saved at 300 dpi, 1200 dpi, and 2400 dpi – but it’s still the same 2700 x 3600 pixel source file. This is why you don’t use the term ‘dpi’ when referring to your source file but instead focus on the total pixel dimensions (w x h).
How does a source image saved at 300 dpi look photo quality when printed at 2400 dpi?
As mentioned in the previous section, the source image’s dpi is irrelevant and doesn’t translate to printer resolution. Instead, what’s important is the total pixel dimensions (w by h, or 2700 x 3600 as an example) of the source file. What ‘dpi’ it’s saved at is not important. Large format poster printing uses commercial RIP software (raster image processing) that takes the source image and rasterizes it to the 2400 dpi used by the printer. It’s a complicated process that you don’t need to worry about other than knowing that our high quality RIP software (we use Onyx Thrive, the industry leader), to take your source image and ‘blow it up’ to the dpi used by the printer to create an ultra high quality photographic print.
You can find more information about image resolution and how it works in large format printing in our resolution article. You can also use our File Quality check to test your image to see how large it can be printed without losing quality.
Print resolution is focused on the quality of printed materials, while screen resolution pertains to the clarity and detail of images displayed on digital screens. It’s important to understand these differences to ensure that images are appropriately prepared and optimized for their intended use, whether in print or digital formats.