tailieunhanh - Tài liệu Photoshop cs5 by Dayley part 50

kênh màu là một thành phần cốt lõi của cả hai màu sắc và hình ảnh màu xám. hình ảnh màu bao gồm các kênh màu riêng biệt mà, khi kết hợp, tạo nên màu sắc trong hình ảnh. Tìm hiểu về các kênh màu sắc và các công cụ mà Photoshop cung cấp sẽ giúp bạn tận dụng tốt hơn các dữ liệu màu trong hình ảnh của bạn. | CHAPTER Channels Color channels are a core component of both color and grayscale images. Color images are composed of separate color channels that when combined make up the colors in the image. Understanding the color channels and the tools that Photoshop provides will help you make better use of the color data in your images. Photoshop provides two main tools to help you manipulate and manage the color channels in images the Channel Mixer and the Channels panel. Using these tools you can see manipulate and even create channels in your image to increase your options when making selections and adjustments. This chapter discusses using the Channel Mixer to mix swap and combine the color data in your images and using the Channels panel to manage channels create and use alpha channels and create spot color channels. IN THIS CHAPTER Using the Channel Mixer to enhance grayscale Understanding the Channels panel Creating duplicating splitting and merging channels Creating and using alpha channels Adding spot color channels to images Understanding Color Channels In Chapter 4 we discussed how the images that we see are just light emitted from a computer screen or reflecting off a photo. We also discussed that the colors we see can be divided into the levels of three frequency ranges of light-stimulating receptors in the eye. Photoshop uses this same concept to represent digital images. Each pixel in a color digital image contains a series of values that define the actual color of the pixel. For example each pixel in an RGB image contains a value describing the level of red a value describing the level of green and a value describing the level of blue. A channel is the series of values for only one color for the entire image. For the red channel each pixel contains only one value describing the level of 341 Part III Selections Layers and Channels red. Splitting the image into individual color channels allows Photoshop to provide some very powerful tools when editing images .