72 dpi resolution or 300 dpi for digital solutions
Most people think they know what dpi means. Unfortunately, that isn’t actually always the case, because the majority is wrong. A picture or a digital image doesn’t actually have a dpi value. Read on for a full explanation.
Dpi or ppi – Which one is it?
Dpi stands for “dots per inch”. When an image is produced, dpi describes the dot density, which gives a value to the level of detail of the screened visuals. It technically describes printed dots per inch. Ppi, or “pixels per inch”, determine the size of an image in relation to the screen resolution in pixels.
A pixel contains color information. Overall this means that the dpi value tells you how many printed dots are in a pixel square. People often refer to dpi as resolution – that’s actually a mistake. The resolution of an image is usually given in ppi, because it is about pixels, not about the dots that are needed for printing. Monitors don’t have dots, they have pixels, so when talking about screens and monitors, ppi is actually also the one to use .
What does “72 dpi resolution” or “300 dpi resolution” mean?
And because of that, dpi isn’t used in web design, either, because here only pixel matter. Many web designers still encounter the mysterious “72 dpi” or “300 dpi”, but it only means that these terms are used mistakenly when talking about digital images. This is probably the case because frequently used programs like Photoshop, give users the option of changing the resolution manually, even though this is only confusing meta-data, that should really be called ppi.
In reality this information is only useful to layout programs like InDesign, by telling it in what size an image should be loaded into the program in relation to the page you’re working on. In the end, these programs are used to bring something to paper. If you save an image with a size of 100×100 pixels, once with a resolution of 72 dpi and once with 300 dpi, you will see that both images still are 100×100. The “resolution” has no effect on a digital image.
Graphic designers on the other hand do think about the dpi value, because they have to think about what the image will look like printed. So they’re always assuming the best resolution possible. For them, the value shows how many dots per inch will be printed onto a piece of paper to print the image. In this case, ppi is less important.
Conclusion: Images on a screen
The level of detail of an image when it is produced on a monitor is not only dependent on the number of pixels, but also on the size of the displayed image in inches. Dpi value and therefor specifications like “72 dpi resolution” or “300 dpi resolution” are irrelevant where specifications about length and width are not needed.
The pixel density however depends only on the monitor that is displaying an image. Once it’s clear how large the image is that’s supposed to be displayed, you can determine the resolution that is needed. You yourself actually don’t have any influence on how large a pixel is being displayed on any screen.
So without the size, you don’t have a real ppi value. And since it doesn’t have any influence on the quality of the image, you could change it however you like.