Write details about image size brush and color
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What are pixels?
The term pixel is short for "picture element", and pixels are the tiny building blocks that make up all digital images. Much like how a painting is made from individual brush strokes, a digital image is made from individual pixels.
In Photoshop, when viewing an image at a normal zoom level (100% or less), the pixels are usually too small to notice. Instead, we see what looks like a continuous image, with light, shadows, colors and textures all blending together to create a scene that looks much like it would in the real world (image from Adobe Stock):
A digital image open in Photoshop. Image credit: Adobe Stock.
A closer look at pixels
But like any good magic trick, what we're seeing is really an illusion. And to break the illusion, we just need to look closer. To view the individual pixels in an image, all we need to do is zoom in. I'll select the Zoom Tool from the Toolbar:
Selecting the Zoom Tool.
Then, I'll click a few times on one of the woman's eyes to zoom in on it. Each time I click, I zoom in closer. And if I zoom in close enough, we start seeing that what looked like a continuous image is really a bunch of tiny squares. These squares are the pixels:
Zooming in closer reveals the individual pixels.
And if I zoom in even closer, we see that each pixel displays a single color. The entire image is really just a grid of solid-colored squares. When viewed from far enough away, our eyes blend the colors together to create an image with lots of detail. But up close, it's pixels that create our digital world:
A close-up view of image pixels, each displaying a single color.
The Pixel Grid
Notice that once you zoom in close enough (usually beyond 500%), you start seeing a light gray outline around each pixel. This is Photoshop's Pixel Grid, and it's there just to make it easier to see the individual pixels. If you find the Pixel Grid distracting, you can turn it off by going up to the View menu in the Menu Bar, choosing Show, and then choosing Pixel Grid. To turn it back on, just select it again:
Going to View > Show > Pixel Grid.
Zooming back out to view the image
To zoom out from the pixels and view the entire image, go up to the View menu and choose Fit on Screen:
Going to View > Fit on Screen.
And now that we're zoomed out, the individual pixels are once again too small to notice, and we're back to seeing the illusion of a detailed photo:
At normal viewing distances, pixels blend together to create the image.
See our complete guide to navigating images in Photoshop
What is image size?
So now that we know that pixels are the tiny squares of color that make up a digital image, let's look at a related topic, image size. Image size refers to the width and height of an image, in pixels. It also refers to the total number of pixels in the image, but it's really the width and height we need to care about.
The Image Size dialog box
The best place to find the image size information is in Photoshop's Image Size dialog box. To open it, go up to the Image menu and choose Image Size:
Going to Image > Image Size.
In Photoshop CC, the Image Size dialog box shows a preview area on the left, and details about the image size on the right. I'll be covering the Image Size dialog box in more detail in the next tutorial. For now, we'll just look at the information we need:
The Image Size dialog box in Photoshop CC.
The pixel dimensions
The width and height of an image, in pixels, are known as its pixel dimensions, and in Photoshop CC, we can view them next to the word Dimensions near the top of the dialog box. Here we see that my image has a width of 4509 pixels (px) and a height of 3000 pixels:
Photoshop CC includes a new Dimensions option at the top.
If the dimensions are shown in a measurement type other than pixels, like inches or percent, click the small arrow next to the word "Dimensions" and choose Pixels from the list:
The dimensions can be displayed in different measurement types.
This tells us that my image contains 4509 pixels from left to right, and 3000 pixels from top to bottom:
The pixel dimensions of the image.
Finding the total number of pixels
To figure out the total number of pixels in the image, we just need to multiply the width and height values together. So in this case, 4509 x 3000 = 13,527,000, or roughly 13.5 million pixels. You don't really need to know the total number of pixels. But as you gain more experience with resizing images, you'll find that knowing the total number of pixels beforehand will give you a good idea of how large you can print the image, as we'll see next when we look at image resolution.