Điều chỉnh các mức cụ thể từ hình ảnh Một tính năng hữu ích của công cụ Curves là khả năng lựa chọn một mức độ trực tiếp từ hình ảnh. Điều này cho phép bạn chỉ cần chọn một khu vực cụ thể của hình ảnh dựa trên những gì màu sắc / nhạc chuông bạn nhìn thấy. Để điều chỉnh các mức từ hình ảnh, nhấp vào nút nhấn-và-kéo trong công cụ Curves (xem hình 4,14) | Chapter 4 Understanding Colors Histograms Levels and Curves Tip You should adjust the input levels before you create your curve because adjusting the input levels afterward results in changes to the curve. Adjusting specific levels from the image A useful feature of the Curves tool is the ability to select a level directly from the image. This allows you to simply select a particular area of the image based on what colors tones you see. To adjust the levels from the image click the click-and-drag button in the Curves tool refer to Figure . Then use the mouse to select a pixel in the image containing the tone you want to adjust. A new point is created on the curve. While holding down the mouse button you can move the mouse up and down to adjust the level of that point. Creating a freehand line If 16 points on the curve line is not enough you can create your own line by clicking on the Freehand Curve button refer to Figure . The Freehand Curve button allows you to draw a freehand line directly on the curve window instead of using points to create the curve. The freehand curve can be used by itself to create the curve. You can use the Freehand Curve tool to make slight nonsmooth adjustments to the curve after you have created it with points. Only the areas of the curve that you draw with the Freehand tool are corrected. Tip You can convert a freehand line into a points curve by clicking the points curve button. This is helpful if you need to make some additional adjustments to the points curve after you change it using the Freehand tool. Using the eyedroppers The eyedroppers work the same way for the Curves tool as discussed earlier in the Histogram tools section. Adjusting the image first with the eyedroppers sometimes gives you a better base to start from when making the tonal corrections with the curve. Working in Different Color Modes Photoshop provides several color modes that help when working with images. Ultimately as we discussed earlier in this .
