What is the difference between DPI, Resolution, and Pixel?
When terms like resolutions, pixels, and DPI are used most people rarely understand that these words are used to explain a digital image file and are all related one way or the other. Are you the one who often gets confused between DPI, resolution, and pixel? Are these words sounding alien to you?
Understanding these terms will help you a lot in printing the right quality, optimize pictures for the web and also will save your time and efforts.
In this article, the relationship between DPI, pixel, and resolution will be demystified and also you will get to know that how all these can impact the quality of your picture from a printing perspective.
What is Pixel?
What makes up a digital picture on your computer/mobile screen is basically called a pixel. If a picture is opened in any image editing program on Mac/PC and then zoom in enough, you will notice that the picture is a precisely organized mixture of equal and small-sized squares. All these squares are called pixels and they are organized in columns and row patterns.
The total amount of pixels and how these pixels are divided are the two important aspects that are needed to understand resolution.
Pixel Count
Pixel count is the total number of pixels that form an image. The formula to calculate resolution is the same as the one to calculate the area of a rectangle; multiplication of length by height. For instance if an image has 4500 pixels on the horizontal side and 3000 on vertical side then you get 13500,000. Because this is an unpractical number, it is divided by a million in order to convert it into megapixels, so the megapixel in this case is 13.5.
Pixel Density
Pixel density is the distribution of all the pixels that you have. Here the resolution is often expressed in DPI which is basically the short form of dots per inch. So if you notice 72 dpi in an image it means that the image will have 72 pixels per inch.
The final size of the photo depends upon the resolution that you go for. If a picture is 4500×3000 pixels it means that this image will print at 15×10 inches if the resolution is set to 3000 dpi but at 72dpi it will be 62.5×41.6 inches. Here the print size changes but the photo is not being resized only the existing pixels are reorganized.
Relation between Pixel and Resolution
A high-resolution image has many pixel families in its composition and that is why such pictures have high pixel density. For a picture to have a better and greater resolution it must have a greater number of pixels. A picture that has low resolution will automatically have fewer pixels and less definition and details.
The resolution of any picture is defined by these calculations:
PPI: It is pixel per inch. PPI is linked with digital devices screens. A pixel is equal to the point of light coming from any monitor, and then PPI utility is to report the pixels quantity on a screen inch with the same 2.54cm.
DPI: It is Dots per inch. It is just like PPI. The only difference is that number of points replaces the pixels in a printed inch. If a picture has more dots that means that it will have more detail and sharpness.
Does Resolution Define the Size of the Image?
The answer to this question is both yes and no. The dimensions of an image can be determined through resolution because the higher the picture resolution the better and bigger the dimensions can be. But the opposite is quite common. You can make a file in A4 size with 300 or 1000 dpi without altering the picture dimensions just by adding more color dots and making the image sharper.
Image Size and Image Quality
It is often asked if image size is the quality. The answer to this question is not always. When it comes to resolution the image quality can be linked to the size. But the quality of production can be analyzed in angles, colors, format, and lighting.
Image Size and File Size
People also confuse the image size with file size. Image size is the dimensions of the image and file size is all about the space image will occupy in a hard drive.
How to control and choose file and image size?
Before doing anything you need to choose the outlet of the image, a maximum density is needed here. If you want to upload the image online then 72 dpi is enough but for printing, it is not suggested. In the case of printing, you need 300-500dpi. But this also depends on the type of monitor and printer because each monitor and printer has a slightly different resolution.
Setting DPI in CZUR Scanner Software
The CZUR Shine Pro Book and Document Scanner is a modern technology-based scanner with all the advanced features that are needed for a quality scanning of any document/book within A4 size. The Sensor of this advanced scanner is 5 Megapixel with a resolution of 3280×2460/270 DPI.
The Shine Pro 800 is 8Megapixels with 270 DPI. If you want to change the format from A4 to A3 then the DPI of Shine Pro 800 is 206.
In the advanced CZUR E18 scanner, it is quite easy to set DPI in the scanner’s software. Below is a picture to guide you about the setting:
