📄 第03章 色彩理论与图像文件格式.htm
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style='mso-spacerun:yes'> </span></span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>除了前述的主要色彩模式还有一些不太常用的色彩模式。</span></p>
<h4><span lang=EN-US>1. 索引模式</span></h4>
<p class=MsoNormal><span lang=EN-US><span
style='mso-spacerun:yes'> </span></span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>索引模式也称映射模式，在索引模式下，我们只能使用</span><span lang=EN-US>256</span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>（</span><span lang=EN-US>8bit</span><span style='font-family:
宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman"'>）种颜色。</span></p>
<h4><span lang=EN-US>2. 灰度模式</span></h4>
<p class=MsoNormal><span lang=EN-US><span
style='mso-spacerun:yes'> </span></span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>灰度模式中只存在灰度，最多可以达到</span><span lang=EN-US>256</span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>级灰度。灰度图像中的每个像素都有一个</span><span lang=EN-US> 0</span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>（黑色）到</span><span lang=EN-US>255</span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>（白色）之间的亮度值。灰度值也可以用黑色油墨覆盖的百分比来度量（</span><span lang=EN-US>0% </span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>等于白色，</span><span lang=EN-US>100%</span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>等于黑色）。使用黑白或灰度扫描仪生成的图像通常以“灰度”模式显示。</span></p>
<p class=MsoNormal><span lang=EN-US><span
style='mso-spacerun:yes'> </span></span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>在灰度图像中，色彩饱和度为零，亮度是唯一能够影响灰度图像的要素，亮度是光线强度值，</span><span
lang=EN-US>0%</span><span style='font-family:宋体;mso-ascii-font-family:"Times New Roman";
mso-hansi-font-family:"Times New Roman"'>代表黑色，</span><span lang=EN-US>100%</span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>代表白色。</span></p>
<h4><span lang=EN-US>3. 位图模式</span></h4>
<p class=MsoNormal><span lang=EN-US><span
style='mso-spacerun:yes'> </span></span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>位图模式就是只有黑白两种像素组成的图像。</span></p>
<h3><a name="_Toc75316282"><span lang=EN-US>3.1.3<span
style='mso-spacerun:yes'> </span></span></a><span style='mso-bookmark:
_Toc75316282'><span style='font-family:宋体;mso-ascii-font-family:"Times New Roman";
mso-hansi-font-family:"Times New Roman"'>色彩对比</span></span></h3>
<p class=MsoNormal><span lang=EN-US><span
style='mso-spacerun:yes'> </span></span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>生活中的色彩往往不是单独存在。我们观察色彩时，或是在一定背景中观察，或是几种色彩并列，或是先看某种色彩再看另一种色彩，等等。这样所看到的色彩就会发生变化，形成色彩对比现象，影响心理感觉。</span></p>
<h4><span lang=EN-US>1. 色彩对比 </span></h4>
<p class=MsoNormal><span lang=EN-US><span
style='mso-spacerun:yes'> </span></span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>在色彩对比的状态下，由于相互作用的缘故，与单独见到的色彩是不一样。</span></p>
<h5><span lang=EN-US><span style='mso-spacerun:yes'>
</span>(1) </span><span style='font-family:宋体;mso-ascii-font-family:"Times New Roman";
mso-hansi-font-family:"Times New Roman"'>同时对比和<span class=GramE>继时</span>对比</span></h5>
<p class=MsoNormal><span lang=EN-US><span
style='mso-spacerun:yes'> </span></span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>当两种或两种以上色彩并列配色时，相邻<span class=GramE>两色会互相</span>影响，这种对比称为同时对比。</span></p>
<h5><span lang=EN-US><span style='mso-spacerun:yes'>
</span>(2) </span><span style='font-family:宋体;mso-ascii-font-family:"Times New Roman";
mso-hansi-font-family:"Times New Roman"'>边缘对比</span></h5>
<h6><span lang=EN-US><span style='mso-spacerun:yes'> </span></span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>两种颜色对比时，在两种颜色的边缘部分对比效果最强烈，这种现象称为边缘对比。</span></h6>
<h4><span lang=EN-US>2. 色调对比</span></h4>
<p class=MsoNormal><span lang=EN-US><span
style='mso-spacerun:yes'> </span></span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>在色彩三种属性中以色调差异为主形成的对比称为色调对比。</span></p>
<h4><span lang=EN-US>3. 亮度对比 </span></h4>
<p class=MsoNormal><span lang=EN-US><span
style='mso-spacerun:yes'> </span></span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>在色彩三种属性中以亮度的差异形成的对比称为亮度对比。</span></p>
<h4><span lang=EN-US>4. 纯度（饱和度）对比</span></h4>
<p class=MsoNormal><span lang=EN-US><span
style='mso-spacerun:yes'> </span></span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>在色彩三种属性中以纯度差异形成的对比称为纯度对比。</span></p>
<p class=MsoNormal><span lang=EN-US><span
style='mso-spacerun:yes'> </span></span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>以上对比在实际应用中单独存在的情况比较少，往往是两种或者更多种对比同时存在，只是主次强弱不同而已。</span></p>
<h2 style='margin-top:7.7pt;margin-right:0cm;margin-bottom:7.7pt;margin-left:
0cm'><a name="_Toc75316283"><span lang=EN-US>3.2<span
style='mso-spacerun:yes'> </span>图像文件格式</span></a><span style='mso-bookmark:
_Toc75316283'></span><span lang=EN-US style='font-size:10.5pt;mso-bidi-font-size:
10.0pt;line-height:150%;font-family:"Times New Roman";mso-fareast-font-family:
宋体'><o:p></o:p></span></h2>
<p class=MsoNormal><span lang=EN-US><span
style='mso-spacerun:yes'> </span></span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>要对图像进行处理，不仅要了解图像的色彩模式，还应了解图像文件的类型及保存的方式。</span></p>
<h3><a name="_Toc75316284"><span lang=EN-US>3.2.1<span
style='mso-spacerun:yes'> </span></span></a><span style='mso-bookmark:
_Toc75316284'><span style='font-family:宋体;mso-ascii-font-family:"Times New Roman";
mso-hansi-font-family:"Times New Roman"'>图像文件的压缩方式</span></span></h3>
<p class=MsoNormal><span lang=EN-US><span
style='mso-spacerun:yes'> </span></span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>由于图像文件包含的图像信息量非常大，保存在磁盘上会占据很大的空间，所以一般图像文件都采用压缩的格式。从压缩后图像信息的完整性看，图像文件的压缩分为有损压缩与无损压缩两种。</span></p>
<h4><span lang=EN-US>1. 有损压缩</span></h4>
<p class=MsoNormal><span lang=EN-US><span
style='mso-spacerun:yes'> </span></span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>有损压缩是对图像本身的改变，在保存图像时保留了较多的亮度信息，而将色相和<span class=GramE>色纯度</span>的信息和周围的像素进行合并，合并的比例不同，压缩的比例也不同，由于信息量减少了，所以压缩比可以很高，但图像质量也会相应的下降。</span></p>
<p class=MsoNormal><span lang=EN-US><span
style='mso-spacerun:yes'> </span></span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>利用有损压缩技术可以大大地压缩文件的数据，但是会影响图像质量。</span></p>
<h4><span lang=EN-US>2. 无损压缩</span></h4>
<p class=MsoNormal><span lang=EN-US><span
style='mso-spacerun:yes'> </span></span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>无损压缩是对文件本身的压缩，和其它数据文件的压缩一样，是对文件的数据存储方式进行优化，采用某种算法表示重复的数据信息，文件可以完全还原，不会影响文件内容，对于数码图像而言，也就不会使图像细节有任何损失。</span></p>
<p class=MsoNormal><span lang=EN-US><span
style='mso-spacerun:yes'> </span></span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>无损压缩方法的优点是能够比较好地保存图像的质量，但是相对来说这种方法的压缩率比较低。</span></p>
<h3><a name="_Toc75316285"><span lang=EN-US>3.2.2<span
style='mso-spacerun:yes'> </span></span></a><span style='mso-bookmark:
_Toc75316285'><span style='font-family:宋体;mso-ascii-font-family:"Times New Roman";
mso-hansi-font-family:"Times New Roman"'>位图图像与矢量图形</span></span></h3>
<p class=MsoNormal><span lang=EN-US><span
style='mso-spacerun:yes'> </span></span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>计算机图像文件分为位图图像和矢量图形两大类</span></p>
<h4><span lang=EN-US>1. 位图图像</span></h4>
<p class=MsoNormal><span lang=EN-US><span
style='mso-spacerun:yes'> </span></span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>位图图像也叫做栅格图像，</span><span lang=EN-US>Photoshop</span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>以及其他的绘图软件一般都使用位图图像。位图图像由像素组成。像素是组成位图图像的最小单位，是图像中的一个颜色点。</span></p>
<p class=MsoNormal><span lang=EN-US><span
style='mso-spacerun:yes'> </span></span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman"'>位图适用于具有复杂色彩、亮度多变、虚实丰富的图像。使用位图格式的绘画程序叫做位图绘画程序，例如</span><span
lang=EN-US>Adobe Photo</span><span lang=EN-US style='mso-hansi-font-family:
宋体'>shop</span><span style='font-family:宋体;mso-ascii-font-family:"Times New Roman"'>。</span><span
lang=EN-US style='mso-hansi-font-family:宋体'><o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><span
style='mso-spacerun:yes'> </span></span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman"'>位图占用存储空间较大。常见有</span><span
lang=EN-US style='mso-hansi-font-family:宋体'>PCX</span><span style='font-family:
宋体;mso-ascii-font-family:"Times New Roman"'>、</span><span lang=EN-US
style='mso-hansi-font-family:宋体'>BMP</span><span style='font-family:宋体;
mso-ascii-font-family:"Times New Roman"'>、</span><span lang=EN-US
style='mso-hansi-font-family:宋体'>DLB</span><span style='font-family:宋体;
mso-ascii-font-family:"Times New Roman"'>、</span><span lang=EN-US
style='mso-hansi-font-family:宋体'>PIC</span><span style='font-family:宋体;
mso-ascii-font-family:"Times New Roman"'>、</span><span lang=EN-US
style='mso-hansi-font-family:宋体'>GIF</span><span style='font-family:宋体;
mso-ascii-font-family:"Times New Roman"'>、</span><span lang=EN-US
style='mso-hansi-font-family:宋体'>TGA</span><span style='font-family:宋体;
mso-ascii-font-family:"Times New Roman"'>和</span><span lang=EN-US
style='mso-hansi-font-family:宋体'>TIFF</span><span style='font-family:宋体;
mso-ascii-font-family:"Times New Roman"'>等。</span><span lang=EN-US
style='mso-hansi-font-family:宋体'><o:p></o:p></span></p>
<h4><span lang=EN-US>2. 矢量图形</span></h4>
<p class=MsoNormal><span lang=EN-US><span
style='mso-spacerun:yes'> </span></span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>矢量图形由矢量定义的直线和曲线组成，</span><span lang=EN-US>Adobe Illustrator</span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>、</span><span lang=EN-US>CorelDraw</span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>、</span><span lang=EN-US>CAD</span><span style='font-family:
宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman"'>等软件是以矢量图形为基础进行创作的。矢量图形根据轮廓的几何特性进行描述。图形的轮廓画出后，被放在特定位置并填充颜色。移动、缩放或更改颜色不会降低图形的品质。</span></p>
<p class=MsoNormal><span lang=EN-US><span
style='mso-spacerun:yes'> </span></span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>矢量图形是用一组指令集合来描述图形的内容，这些指令用来描述构成该图形的所有直线、圆、圆弧、矩形、曲线等图元的位置、维数和形状。</span></p>
<p class=MsoNormal><span lang=EN-US><span
style='mso-spacerun:yes'> </span></span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>矢量图的优点也就在于它在任何解析度下输出时都同样清晰。因为矢量图形与分辨率无关，可以将它缩放到任意大小和以任意分辨率在输出设备上打印出来，都不会影响清晰度。因此，矢量图形是文字（尤其是小字）和线条图形（比如徽标）的最佳选择。</span></p>
<p class=MsoNormal><span lang=EN-US><span
style='mso-spacerun:yes'> </span></span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>由于计算机显示器呈现图像的方式是在网格上显示图像，因此，矢量数据和位图数据在屏幕上都会显示为像素。</span><span
lang=EN-US style='mso-font-kerning:0pt'><o:p></o:p></span></p>
<h3><a name="_Toc75316286"><span lang=EN-US>3.2.3<span
style='mso-spacerun:yes'> </span></span></a><span style='mso-bookmark:
_Toc75316286'><span style='font-family:宋体;mso-ascii-font-family:"Times New Roman";
mso-hansi-font-family:"Times New Roman"'>图像文件格式</span></span></h3>
<p class=MsoNormal><span lang=EN-US style='mso-font-kerning:0pt'><span
style='mso-spacerun:yes'> </span></span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman";mso-font-kerning:0pt'>图像文件格式指的是数字图像以什么方式保存在磁盘上。不同的图像文件格式，其用途会有所不同，用以打开的软件也会有所区别，当然，当前流行的图像软件，一般都能打开不止一种格式的图像文件。</span><span
lang=EN-US>Photoshop</span><span style='font-family:宋体;mso-ascii-font-family:
"Times New Roman";mso-hansi-font-family:"Times New Roman"'>所能打开的图像文件格式有数十种之多。</span><span
lang=EN-US style='mso-font-kerning:0pt'><o:p></o:p></span></p>
<h4><span lang=EN-US>1. PSD格式</span></h4>
<p class=MsoNormal><span lang=EN-US><span
style='mso-spacerun:yes'> </span></span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman"'>这是著名的</span><span
lang=EN-US>Adobe</span><span style='font-family:宋体;mso-ascii-font-family:"Times New Roman"'>公司的图像处理软件</span><span
lang=EN-US>Photoshop</span><span style='font-family:宋体;mso-ascii-font-family:
"Times New Roman"'>的专用格式</span><span lang=EN-US>Photoshop Document</span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman"'>（</span><span
lang=EN-US>PSD</s⌨️ 快捷键说明
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