When you work with computer graphics, you need to pay attention to color space. Color space affects how images are printed or displayed on a screen. What is color space? In this video, author Richard Harrington explains what color space is, how it is used when you edit a digital image, and how to change between the different types.
- When working with computer graphics, it's important to pay attention to color space. This will affect how the images are printed or displayed later on as you move through the digital imaging process. Color space affects many things. Essentially it is a specific organization of color within the file. How the individual colors are represented. Now this can be useful because it allows for color to be reproducible in both analog and digital representations.
Analog being things like print, and digital being computer displays. The three most common types that you'll encounter are going to be RGB, or Red Green Blue color model. Grayscale, that lacks color, but simply uses one detail channel for gray values. And CMYK, Cyan, Magenta, Yellow, and Key, or black depending upon how you like to think of it. Color space can also be referred to as image mode by some software applications.
When working on computers or using an attached display, the most common model you're going to encounter is RGB, or one of its subtle variants. The RGB model is an additive model. As equal colors add up, they equal white. Red, green, and blue. So for example, if pure values of red and green mix together, they'll create yellow. Red and blue mixed together will create magenta, and blue and green mixing together will create cyan.
If an equal presence of all of those colors are visible, then you get pure white light. Now this is important because this is an additive model. The colors combine and create brighter areas. Typically when working with a computer display or a television, there will actually be red, green, and blue elements that control the color of the pixels. Now this is referred to as additive color mixing. The colors combine and get brighter.
It describes what type of light is needed in order to produce a particular color. Different mixtures of red, green, and blue can reproduce almost every color that we see in the visible spectrum. RGB can hold individual values for both the red, green, and blue channels. You may also encounter RGBA. This is the alpha channel, and this can contain transparency data. We'll talk more about transparency in just a moment.
There are some other color spaces that you'll encounter that are quite similar to RGB. sRGB, which is most commonly used for web graphics. Adobe RGB and ProPhoto RGB, that are often used for things like Adobe software, or computer graphic software. And scRGB and CIE RGB, which are used in displays and other formats. We've talked about additive, but what about subtractive, the other side? Well, this is the CMYK model, and it's most commonly used for printed graphics.
Cyan, magenta, yellow, and black, or key. In this case, when you combine cyan, magenta, and yellow inks, they can reproduce additional colors. And you'll also encounter key or black. Now what happens here is that you've encountered this in the past and might not have even thought about it. If you've had to buy ink cartridges for a typical inkjet printer, most people these days either get a combination cartridge that contains all of the inks in one, or separate cartridges that might break it out as cyan, magenta, yellow in one container, or each of those separately even, and black broken out as well.
Now some printers will go a step further and create additional subsets like light cyan, et cetera, but for the most part this is pretty straightforward. And what happens is is that this ink is subtracted, so as the ink is on the page and the light hits it, it generates the color based upon what's reflected. So the CMYK model used subtractive color mixing. In fact you might notice here that those subtractive colors are there, and when magenta and yellow combine, they make red.
Yellow and cyan make green, and cyan and magenta make blue. This is literally the opposite of what was happening over in the RGB space. And that makes sense since additive and subtractive are opposites. This is most commonly used in the printing process, and as the ink is applied to the page, it will affect what light is reflected. It's the reflected light that we perceive as a color. The ink subtracts color from white and thus creates the image.
Most commonly, you'll print on white paper, and as such, these colors are pretty understandable. If you change the color of the paper, then the ink will have different results. CMYK is going to store its values for the cyan, magenta, yellow, and black areas, and when it calls upon the printing device, these inks will be discharged and applied to the page. Now most of the time we're just going to work with RGB graphics. You'll find that Microsoft Office products are fine with those, and the printer will typically do the conversion from RGB to CMYK.
However, if you find yourself working with professional graphics, or other applications, you might encounter some CMYK graphics in your workflow. If this is the case, you might need to make steps to convert those graphics.
- Reviewing essential technological concepts
- Why does file format matter?
- JPG, PNG, and other raster formats
- Converting file formats with Adobe tools and free utilities
- Resizing images
- Matching visual style
- Adjusting the exposure, color, and size of an image
- Making essential image adjustments in Microsoft Word and PowerPoint
- Adjusting images with online image editors
- Adjusting images in a PDF file with Acrobat Pro
- Intellectual property rights