# Relationship between pixels and resolution

### Pixels and Resolution

Each pixel in a digital photo adds to the size of the image file. If you pack your image with pixels, you have to deal with its huge file size. To keep your pixel count. A high resolution image is an image with high density of pixels, that is, with several families of pixels in its composition. The greater the number. In today's article, we will discuss the underlying relationship between these two popular tech jargons, display resolution and pixel density.

Pixels have subpixels, which are composed of three colors, namely RGB Red, Green, Blue — the primary colors Pixels do not get compressed when you pack more of them in a screen.

But instead, smaller pixels have to be created for a sharper display. Here are a few images to help you visualize what we have said before. If you have come across the x resolution also known as HDthen it simply means the screen has pixels in width and pixels in height.

### The Relationship Between Display Resolution and Pixel Density (PPI) - Mr. Geek

Put it simply, a screen A can have the same number of pixels as screen B, but screen B can have a higher PPI if its diagonal screen size is lesser. This means, more pixels packed into a small area gives a sharper image due to High PPI and automatically a higher resolution of the device. Take the 15 inch MacBook Pro Retina as an example.

Display resolution vs. PPI

The image below shows the mathematics involved in calculating the PPI of a device in 2 steps. The sample device is an iPhone 5 with Retina Display.

In step 1, you calculate the diagonal resolution of the iPhone 5 display in pixels. With the final result in hand, you can compute the PPI by dividing the diagonal resolution pixels with the diagonal size inches.

Now, if the iPhone 5 had a smaller screen size with the same number of pixels, the denominator in the PPI equation would reduce hence giving you a higher PPI. This is obvious as there would be more pixels per inch, hence a higher pixel density. Like wise, if the screen size is constant and the pixels are increased, you would again get a higher PPI. What is a pixel? A digital photo is not one non-dividable thing. The amount of these pixels and the way they are distributed are the two factors that you need to consider to understand resolution.

Pixel count The first kind of resolution refers to the pixel count which is the number of pixels that form your photo. In order to calculate this resolution you just use the same formula you would use for the area of any rectangle; multiply the length by the height. For example, if you have a photo that has 4, pixels on the horizontal side, and 3, on the vertical size it gives you a total of 13, Because this number is very unpractical to use, you can just divide it by a million to convert it into megapixels.

Pixel density The other kind of resolution is about how you distribute the total amount of pixels that you have, which is commonly referred as pixel density. Now, the resolution is expressed in dpi or ppiwhich is the acronym for dots or pixels per inch.

So, if you see 72 dpi it means that the image will have 72 pixels per inch; if you see dpi means pixels per inch, and so on. The final size of your image depends on the resolution that you choose. If an image is x pixels it means that it will print at 15 x 10 inches if you set the resolution to dpi, but it will be While the size of your print does change, you are not resizing your photo image fileyou are just reorganizing the existing pixels.

In summary, no resolution is not the same as size, but they are related. So quantity equals quality?

• Difference between Pixel and Resolution
• How to Understand Pixels, Resolution, and Resize Your Images in Photoshop Correctly

Because of the aforementioned correlation between size and resolution, a lot of people think that megapixels equal quality. And in a sense it does because the more pixels you have to spread out, the higher the pixel density will be.

## How Do Pixels and DPI and Resolution and Picture Size and File Size All Relate?

However, on top of the quantity you should also consider the depth of the pixels, this is what determines the amount of tonal values that your image will have. In other words it is the number of colors per pixel. For example, a 2-bit depth can store only black, white and two shades of grey, but the more common value is 8-bit. This is already more that the eye can distinguish which means that bit or bit will look relatively similar to us.

Of course, this means that your image will be heavier even of the size is the same, because there is more information contained in each pixel. This is also why quality and quantity are not necessarily the same. Therefore quantity helps, but also the size and depth of each pixel determine the quality. This is why you should look all the specs of the camera and its sensor and not just the amount of Megapixels.

How to choose and control image size and file size?

First of all, you need to choose the outlet for your photo, there is a maximum density that you need.