tailieunhanh - Photoshop CS4 for Dummies phần 4

" Máy ảnh độ phân giải: kỹ thuật số máy ảnh chụp từng hình ảnh trong một số cụ thể của các điểm ảnh. Kiểm tra hướng dẫn sử dụng máy ảnh của bạn hoặc mở một trong những hình ảnh trong Photoshop và chọn ảnh ➪ Kích thước ảnh. Hãy nhìn vào số lượng điểm ảnh mà máy ảnh hồ sơ cho chiều rộng và chiều cao của bạn. nhân | Chapter 6 Making Color Look Natural 111 Converting between color modes or gamuts done with the Image Mode menu can reduce the quality of your image by compressing different colors into a single color value. You would not for example want to convert from RGB which has a comparatively large number of colors available to CMYK with a more restricted color gamut and then back to RGB. After colors are compressed by a conversion you can t restore their original values by converting back to a wider gamut. Does a color model make a difference Although the image itself has a single color mode you can use any of the available color models when defining a color in Photoshop. Say for example that you re preparing to use the Brush tool to paint some artistic elements for your latest project. The project is in RGB mode because you ll be printing it with your inkjet printer. You can use the Color panel to define your foreground color any way you please RGB CMYK Grayscale Lab or even HSB hue saturation brightness which isn t available as a color mode just a color model . It doesn t matter how you set up the Color panel which you do through the panel s menu as shown in Figure 6-4. When you add the color to your image Photoshop uses the nearest RGB or CMYK equivalent. Notice that the Color panel menu in Figure 6-4 doesn t list Duotone or Multichannel. Those are color modes only not color models. A couple of other things to note about working with the Color panel The warning triangle visible in Figure 6-4 in the lower-left corner of the panel indicates that the selected color is outside the CMYK color gamut. Clicking the swatch to the right would select the nearest equivalent color. If that is you were actually working in CMYK Figure 6-4 Choose your preferred color model from the Color panel menu. mode. Also note that the background swatch is selected in the panel high- lighted with a black outline click the foreground swatch to make changes to .