Image quality in a coded language?

Fortunately, you don't need to be an engineer or a secret agent to understand these two terms!

Let us first begin by defining them:

DPI = Dots Per Inch. This term refers to the number of dots required to create an image.

PPI = Pixels Per Inch. This term refers to printing screens.

What we are talking about here is the resolution, or the capacity to render the tiniest details of an image. The term DPI is that most often used for digital imaging, while PPI is more commonly employed in the printing industry.

Image Capture (camera and digitizing)

Most of the time, digital camera resolutions are indicated in "megapixels". For example, a 16.3 megapixel camera has a resolution of 4928 dpi x 3264 dpi, which adds up to 16.3 million pixels.

The higher the resolution, the smaller the pixel size, and the finer the recorded details will be.

See these examples below for a demonstration of this formulation:

600 dpi schema

3000 dpi schema


600 dpi image

3000 dpi image


In this case, DPIs have very little to do with the quality of the finished image. A thermal printer with a resolution of 312 dpi will give results that are as good as those obtained with an ink jet printer of 1400 dpi!

Here DPIs only indicate different print qualities for the same type of printer.

To obtain quality prints with an ink jet printer, a more important factor is the diameter of droplets in PICTOLITRES. The higher the number of pictolitres (i.e. 4 pictolitres), the more precise the rendering will be. The number of base colors used 6, 8 or 11 is also an important aspect to consider when it comes to the quality of the final image.

PS: Read our photo advice on printing to find the ideal resolution your camera must have according to the printing format desired.

Resolution vs compression in JPEG?

A high level of JPEG compression could misguide you on your reading of your image quality. Despite a good resolution, if it is too high, the effect will alter the outline and clarity of the subjects you’ve just photographed. The advanced amateur will choose to save his images in a RAW format file in order to get more flexibility in treating the image and obtain an image with maximum quality in a TIF format, not compressed. Please refer to our photo advice on RAW files.


In choosing a camera, the desired results should be your first consideration. Would you like to make souvenir photos, enlargements or Web images? Different resolutions (DPI) for as many uses.

Go for it, and Happy Shooting

With the cooperation of Jacques Bourdage, PFE.