Perceptions of the visible world were greatly altered by the invention of photography in the middle of the nineteenth century. In particular, and quite logically, the art of painting was forever changed, though not always in the ways one might have expected. The realistic and naturalistic painters of the mid- and late-nineteenth century were all intently aware of photography—as a thing to use, to learn from, and react to.

　　Unlike most major inventions, photography had been long and impatiently awaited. The images produced by the camera obscura, a boxlike device that used a pinhole or lens to throw an image onto a ground-glass screen or a piece of white paper, were already familiar—the device had been much employed by topographical artists like the Italian painter Canaletto in his detailed views of the city of Venice. What was lacking was a way of giving such images permanent form. This was finally achieved by Louis Daguerre (1787-1851), who perfected a way of fixing them on a silvered copper plate. His discovery, the "daguerreotype," was announced in 1839.

　　A second and very different process was patented by the British inventor William Henry Talbot (1800-1877) in 1841. Talbot's "calotype" was the firstnegative-to-positive process and the direct ancestor of the modern photograph. The calotype was revolutionary in its use of chemically treated paper in which areas hit by light became dark in tone, producing a negative image. This "negative," as Talbot called it, could then be used toprint multiple positive images on another piece of treated paper.

　　The two processes produced very different results. The daguerreotype was a unique image that reproduced what was in front of the camera lens in minute, unselective detail and could not be duplicated. The calotype could be made in series, and was thus the equivalent of an etching or an engraving. Its general effect was soft edged and tonal.

　　词汇解析：

　　perception n. 看法;感知

　　alter v. 更改

　　logical adj. 逻辑的;合乎逻辑的

　　intent adj. 坚决的;专注的

　　react v. 作出反应;起不良反应;反抗

　　impatient adj. 无耐心的

　　topographical adj. 地形的

　　permanent adj. 永久的;不断发生的

　　silver n. 银;银器

　　patent n. & v. & adj. 专利;得到...专利;显而易见的强调

　　ancestor n. 祖先;物种原型

　　multiple adj. & v. 多功能的;倍数

　　reproduce v. 复制;重演

　　duplicate v. & n. 复制;复制品

　　etch v. 凿刻;铭刻

　　engrave v. 刻上

　　tonal adj. 声调的

　　难句解析：

　　The realistic and naturalistic painters of the mid- and late-nineteenth century were all intently aware of photography—as a thing to use, to learn from, and react to.十九世纪中期与后期的现实主义和自然主义画家都高度关注摄影术，将其当作一门可以使用、借鉴而且要适应的技术。

　　The images produced by the camera obscura, a boxlike device [that used a pinhole or lens to throw an image onto a ground-glass screen or a piece of white paper], were already familiar—the device had been much employed by topographical artists like the Italian painter Canaletto in his detailed views of the city of Venice.当时针孔照相机已经为大家所熟识，它是一种是用小孔或透镜将摄影投射到毛玻璃屏或一张白纸上的盒状设备，这种设备已经为很多地貌风景画家所用，像意大利画家卡纳莱托就用它详细记录了威尼斯城。

　　The calotype was revolutionary in its use of chemically treated paper in which areas hit by light became dark in tone, producing a negative image. This "negative," as Talbot called it, could then be used to print multiple positive images on another piece of treated paper.卡罗式摄影法革命性地使用了化学处理的纸片，纸片上受到光照射的区域的色调会变暗于是产生了负像。这种被塔尔博特称为“负片”的东西随后会被用于在另一张化学处理的纸片上洗印多张正像。

　　The calotype could be made in series, and was thus the equivalent of an etching or an engraving. Its general effect was soft edged and tonal.而卡罗式摄影法可以洗出多张照片，因此相当于蚀刻术或雕刻术。其整体的效果是轮廓和色调模糊。

　　填空

　　本篇文章介绍了两种摄影技术_____和__________技术诞生于1839年;_____技术诞生于1841年;两种摄影技术产生了不同的效果：_____得到唯一一张影像;_____可以洗出多张照片

　　Answers:

　　Daguerreotype, calotype

　　Daguerreotype, calotype

　　Daguerreotype, calotype