Chương 4: Tìm hiểu về màu sắc, biểu đồ, Levels, và Curves Phần Trăm: Điều này hiển thị tỷ lệ điểm ảnh với mức độ mà ở hay dưới các mức dưới con trỏ chuột. tỷ lệ phần trăm được tính toán dựa trên tỷ lệ phần trăm của tất cả các điểm ảnh trong hình ảnh, vì vậy mức độ xa nhất bên trái là 0% và mức độ xa nhất bên phải là 100%. Cache Level: Điều này hiển thị các thiết lập cho cấp bộ nhớ cache hiện tại nếu Cache sử dụng cho biểu đồ được chọn. | Chapter 4 Understanding Colors Histograms Levels and Curves Percentile This displays the percentage of pixels with intensity levels that are at or below the level under the mouse cursor. The percentage is calculated based on a percentage of all pixels in the image so the level to the farthest left is 0 and the level to the farthest right is 100 . Cache Level This displays the setting for current cache level if the Use Cache for Histograms is selected in the Preferences dialog box. Adjusting images with the histogram tools Some Photoshop tools provide histogram tools to help you better see how to adjust and correct images. Although we cover using the tools such as the levels adjustments in subsequent chapters you need to know generally how they work. The tools that Photoshop provides all have the same basic components. As an example look at the Levels tool in Figure . The input levels are represented as a histogram. Below the histogram view are three triangular control handles that allow you to easily adjust the input levels of the channel in the image. To the right of the histogram are three eyedropper tools that allow you to select dark light and midtone points in the image to quickly adjust the input levels of the channel. The following sections discuss briefly how to use these tools. We discuss the tools in more detail in subsequent chapters as we get into correcting and adjusting images. FIGURE The Levels tool showing the histogram utility that Photoshop provides in several different tools Control handles Using the handles to adjust the histogram The dark handle on the left controls the minimum level for the channel the white handle on the right controls the maximum level for the channel and the middle gray handle controls the balance of middle tones between the high and low levels. 107 Part I Getting Started with Adobe Photoshop CS5 So what do the histogram controls really do To help clarify notice that most of the level values in the histogram shown in
