When choosing a home or office printer, most people look primarily at the price, while a minority look at print speed and ink consumption. Almost no one, however, takes into account the DPI value. This determines the quality of the resulting print.
Table of Contents
- What is DPI?
- Is DPI the same as the resolution?
- How DPI Relates to Inkjet Printers?
- Why 300 is considered the “standard” PPI of a digital camera?
- I have also seen 2400 x 600 or 600 x 1200 printer DPIs. What does it mean when DPI has two values?
- Human eye visible resolution limit
- Which consumes more ink 600 dPI or 1200 dPI?
- It is the print head that determines the DPI value
- Standard DPI for printed work
What is DPI?
DPI stands for dots per inch, the number of dots (pixels) per a printed line of one inch. It determines the density of printing dots and, therefore, the sharpness (resolution) of the printed image or text. The higher the DPI value, the more detailed the printed material will be.
If the printer prints at 300 DPI, this means that 300 dots (pixels) can fit in a line 1 inch long. At a DPI of 900, it will squeeze three times as many pixels into the same line.
PPI refers to monitor or display resolution. It is the mathematical value that determines how large the pixels will be when printed out on the screen. On the other hand, DPI is the number of physical dots of ink that are laid down in a linear inch of a printed page. Printers translate the pixels into a series of dots using a process called dithering.
Is DPI the same as the resolution?
Dpi describes how many dots per inch can be printed on a physical piece of paper. This is the standard measurement used to determine the quality of images, and both DPI and PPI are often used interchangeably with the term “resolution.”
If you’ve ever wondered whether the dots per inch resolution of your printer is similar to the resolution of your monitor, the answer is no. While both DPI and PPI are ways of measuring resolution, they are fundamentally different.
For example, a printer with a resolution of 300 x 300 dots per inch means it can print at 300 dots per inch for a given width of the paper. This is vastly different from the PPI resolution of, say, your computer monitor, which has a most common resolution of 72 PPI (1920×1080) – 123 PPI (2560×1440).
Even the 4k UHD 24″ (3840×2160) monitors only have a resolution of 180 PPI. Mobile phone displays are in the range between 200 and 300 PPI.
How DPI Relates to Inkjet Printers?
In general, all inkjet printers work the same way, using the same technology. They use a nozzle to spray the ink onto the paper as it moves through the printer. Again, the print quality depends on the resolution of the printer.
Dpi is frequently used as a marketing tool by printers and advertisers to manipulate consumers into buying specific devices, but it’s important to remember the specs that advertisers use to rate a device can be misleading. For example, even though a printer may be advertised as a 4800 dpi printer, the actual print quality will depend on how good the printer’s ink is and the type of paper.
Why 300 is considered the “standard” PPI of a digital camera?
There is nothing like “standard” DPI (dots per inch) or PPI (pixels per inch). Neither for cameras nor printers.
Many people think that the “standard” number of pixels per inch for a digital camera is 300. This number represents the resolution of one of the first digital cameras, the Kodak DCS520, which had a 3.2 Megapixel CCD image sensor capable of capturing 1600 × 1200 pixels.
I have also seen 2400 x 600 or 600 x 1200 printer DPIs. What does it mean when DPI has two values?
The DPI value can also be two-dimensional. They define dots per inch value for a square inch of, say, printed image. If the printer has a DPI of 600 × 1200, then it will print 600 pixels per inch of width and 1200 pixels per inch of height. Is DPI really that important?
It depends on what you’re printing. While you can get by with a DPI of 300 when printing an office document, with photography, you can safely tell the difference between low and high resolution on the first try. And this leads us to question whether the human eye has any DPI limit?
Human eye visible resolution limit
The exact human eye pixel density or resolution limit is very individual. The eye is said to have a pixel density limit of ~300ppi due to the resolution of the retinal fovea. The fovea is a cone-shaped region of the retina responsible for the high-acuity vision and is responsible for the central vision in humans. The fovea only comprises roughly 1-2% of the area of the retina, but it contains ~50% of the total photoreceptors.
Does this mean you get the best quality output when using the highest resolution printer on the market (9600 dots per inch)? No, because the human eye has its limits and perceives print quality identically from a certain print density onwards.
Print resolutions higher than an individual resolution of an eye are no longer recognizable by the eye. The ability to discern detail decreases rapidly with distance from the image. Of course, the ability to focus is individual, with eye defects being significant. However, we can say that you can hardly tell the difference between a photo with a resolution of 1200 and 9600 dots/inch.
Which consumes more ink 600 dPI or 1200 dPI?
While increasing the resolution of a photo printer from 2200 onwards has no effect on our aesthetic experience, it definitely affects our wallet. This is because, at higher DPI, the printer uses more ink (more dots per inch need to be covered).
It is the print head that determines the DPI value
The technology of its print head determines the DPI range of a printer. Different types of printheads can fit different pixel densities per inch:
- Dot-matrix printers (needle printers): 60 to 90 DPI,
- Inkjet printers: 600 to 9600,
- Laser printers: 600 to 2400.
Standard DPI for printed work
Standard DPI for printing documents
For printing standard, text-based documents, a 300 DPI printer will do the trick.
Standard DPI for photo printing
When printing photos, the resolution is crucial – the resulting quality is primarily determined by the camera you use to take the picture. For example, a device with a resolution of 8 Mpx can record 8 million pixels in a photo – but there is no direct relationship between this value and dots per inch value.
In other words, the camera’s resolution determines how detailed the image you take is. The printer’s resolution then determines how sharp the photo will look on paper.
A printer with a resolution of 600 DPI and above will ensure that your images look good on paper.
If you want to print high-quality photos at home (on high-quality photo paper), reach for a device with a resolution of 1200 × 2400 dpi or higher.
Standard DPI for printing on clothing
The standard resolution for t-shirts, hoodies and other clothing is 300 DPI. This is generally accepted as the standard for printing on clothing and is a good rule of thumb.
T-shirts are usually printed in one of two ways. First, they can be printed with a special dye-sublimation printer to print directly onto the shirt. These printers print at 300DPI and are usually found in specialty shops.
The second way is to print on transfer paper. This is where the image is printed onto special transfer paper, which is run through a heat press. This is usually done at 300DPI or 600DPI, depending on the size of the print.