Join Chris Orwig for an in-depth discussion in this video The foundation of digital imaging: pixels and bit depth, part of Photoshop CS6 for Photographers.
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I need to give you a little bit of an advance warning here because we're about to dig into a complicated topic. We are going to take a look at the foundation of digital imaging pixels and bit depth. Yeah, we are going to take a look at this complicated topic and see if we can make it simple and understandable. So why do pixels and bit depth really matter? Well, if we can understand these topics, it can help us create better images. It also can help us have more control when we are working on our photographs inside of Photoshop.
Well, to really understand these topics, what I think we need to do is to go back in time for a moment. James Clerk Maxwell was a person who discovered that what you could do is you could create a color image with three different colors: red, green, and blue. And it's a really fascinating story if you're interested in photography and the history of photography. But basically, what he discovered is that he could have these three different negatives, he could then shine light through these negatives with a red or a green filter on each of these.
Well, together, these would then create a color photograph. It was actually really just amazing. It was the discovery of color photography. Well, to this day, the same way that we view images when they're created via light is with these three channels: red, green, and blue. And let's say that we have a color, for example, orange. Well, just to kind of create something, to try to illustrate this, we could say that this orange is made up of 240 red, 12 green, and 15 blue.
In other words, it's kind of like mixing paint together, and all that you need is to be able to mix together these three colors and it can give you a huge range of different options. Well, how is that possible? Well, that's possible because of pixels in bit depth. Let's take a look at a photograph, for example,. Well, here we have an image, and if we zoom in on an area of this photograph, we can see that it's made up of all of these different little pixels. Well, what is a pixel? Well, the pixel is the concatenation or combination of two words, picture and element.
At its base it's this small little picture element, and if we are really getting close into one of these little elements, what we will discover is that these are made up of bits. Now the word bit is a combination of these two words, binary and digit. And I know this sounds a little bit abstract here, but let's dig deeper into what a bit actually is. What is a pixel made up of? Well, a bit is some information, and we can have a certain kind of bit depth.
If we have bit depth, you can see that as we have more bits, well, we have larger file size. We have more info. And bits are made up of this whole concept of you can have something which is either on or off. It's binary. We have two options. Well, the more options that we have, the more colors, the more tonality, the more smoothness that we have in an image so that it looks like a photo realistic picture. Let me explain this. Well, here you can see we have one bit. This can either be black or white.
Two bit, we can have black or different shades of gray as we get up to 8 bit or higher. All of a sudden, we have enough variation so that it looks like continuous tone. And this is really the basis for how our digital images are made. In other words, you know when you zoom in close, you can see that this is pixelated. You're seeing all the corners of the pixels. Yet when you have enough information, you see an image as continuous tone. And in the RGB color space, we have these 8 bits of red, of green, and also of blue.
Each of these channels give us 256 possibilities. In other words, as we combine these different colors or tones together, this gives us a chance to create the 16 million colors. And this is all because of bit depth. So when we go back to our photograph, really we are able to see this picture as continuous tone, as all of these beautiful and vibrant colors, because of these pixels. And these pixels really are created by these different pieces or these different bits.
These bits give us options. This as I mention, gives us the ability to view these beautiful photographs, whether we want to see the colors of a sunset or the pictures in a portrait. And where we start to see this in Photoshop-- or where the rubber meets the road--is here. We will discover, say, in our Levels panel that we will have 256 levels, everything from 0 to 255. You can see those levels here. In this histogram, well, it displays information that we have in our photograph.
We will also find this in other places like in curves. Again, we have that grayscale, 256 levels. You'll also notice were viewing this in the RGB composite channel, these three channels together. Or you can target the specific channels, the red, the green, or the blue, and we will also see this, say, in our Channels panel. Here, you can see our image, it's made up of these three different channels together. And as I mentioned in the beginning of this movie, I know that this concept is a little bit complicated.
Yet I want to share this topic with you because this really is the foundation for our digital images. It's really all about how we have pixels and bit depth. And if we can have somewhat of a working understanding of how our digital images are made, well, it can ultimately help us make better images, and it can give us more control. And as we dig into those controls, whether that's levels or curves or the channels, we can start to understand that what we're working with are these different channels. We know why these exist because these give us this continuous tone full-color image.
And by having this just initial familiarity with this whole concept of pixels and bit depth, well, it can just help us out in our overall process as we seek to become better and more efficient at creating compelling digital photographs.
The course details the features and techniques behind enhancing and retouching photos, preparing them for print and online publishing, and much more. Chris demonstrates how to make basic edits in Camera Raw, develop and save color profiles, work with layers and selections, tone and sharpen, and retouch images while retaining their natural character.
Chris also shares some creative tips and project ideas, such as converting a photo to black-and-white and enhancing a portrait with hand-painted masks. The course also covers workflow details, such as organizing images in Bridge and Mini Bridge, optimizing Photoshop preferences, and calibrating your monitor.
- Getting started with Bridge and Mini Bridge
- Setting up color and performance preferences
- Calibrating your monitor
- Improving images with the basic controls in Camera Raw
- Creating, aligning, and organizing layers
- Using masks for removing or blending images and for sharpening
- Working with vibrancy, hue, and saturation controls
- Enhancing color and tone with Levels
- Using Curves and masks to enhance brightness, color, and tone
- Mastering the art of blending modes
- Correcting and replacing color
- Burning and dodging
- Converting to black and white