Wait…what?! But everyone always tells you that 300 dpi is high resolution. Have you been lied to? Well, not exactly. Let me explain:
If your image is 300 dpi, but only 2x2cm in size, you will only be able to print a non-pixelated image at a maximum measurement of 2x2cm. If you print it any larger, say 5x5cm, you will see pixelation, which is loss of image quality. So, technically, the 5x5cm image is still 300 dpi, but it's been stretched to from 2x2cm to 5x5cm, resulting in a pixelated image:
This is a 72 dpi image. You've been told 72 dpi is inferior and low resolution, yet the image is crisp. How is this possible?
While this image might be not be 300 dpi, it is 20.83cm wide at 72 dpi. This means there is enough pixel information contained in the image to be able to print a crisp photo at 5x5cm.
How this plays out in practice:
The easiest way to relay what size photo you need is to start with the size your photo will be printed. Let's say you need a corporate head shot for a magazine article. If the final image will be printed at 6x9cm, you need to ask your photographer for a 6x9cm 300 dpi image. That way, you will be guaranteed the correct resolution for your image. Just asking for a 300 dpi image won't necessarily mean you'll receive the image at the correct size. Make sure to add in the measurements of the image, and you're all set.
One last thing: Remember that while your photo's resolution may look sufficient on screen, that doesn't guarantee it will be high enough resolution to be printed clearly. Always check the size of the photo before printing.
Till next time,
Marinda