Let me guess, you've got Facebook albums full of photos.
让我猜一猜，你脸书的相册里充满了照片。
You have photos on your computer desktop, on your mobile phone, on your bedroom wall.
你的电脑桌面上、手机上、卧室墙上都有照片。
You see photos in magazines and newspapers, on the side of buses, and of course, in your family albums.
你可以在杂志和报纸上，或是公交车的侧面看到照片，当然，在你的家庭相册里也有。
We take photos for granted in a major way.
我们将现在的照相技术视为理所当然。
But, creating a picture that looked exactly like the person or thing that you were photographing wasn't always obvious.
但是，要创造出一幅看起来和人或事物完全一样的图像，也就是你所谓的"摄影"，并非一开始就这么简单。
In fact, in the past, it was a big mystery.
事实上，在过去，摄影就像是一个很大的谜团。
How could you, in essence, take your reflection in the mirror and freeze it in there?
从本质上来看，你怎么可能将镜子反射的影像冻结在那并且带走？
In the 9th century, the Arab scientist Alhazen had come up with the idea of using the camera obscura,
在九世纪，阿拉伯科学家阿哈桑想到了一个使用暗箱的点子，
which was literally a dark room, or box, with a single, small hole in one side that let light through.
和字面上的意思一样，它是个黑暗的空间或是箱子，其中一侧有个小洞，可以让光透进去。
This would project the image outside into the wall inside.
这能够把外面的景象映射到内壁。
During the Renaissance, artists like Leonardo DaVinci used this method to introduce 3-D scenes onto a flat plane
在文艺复兴时期，像莱昂纳多·达芬奇这样的艺术家利用了这个原理，将三维的场景投影在平面上，
so that they could copy things, like perspective, more easily.
于是他们就能更轻易地复制例如透视的影像。
In 1724, Johann Heinrich Schultz discovered that exposing certain silver compounds to light
在1724年，约翰·海因里希·舒尔茨发现了当某种银的化合物暴露在光线之下，
altered their appearance and left marks wherever the light touched.
它们的外观会改变，并且会在接触到光线的地方留下痕迹。
Essentially, Schultz found a way to record the images that Alhazen was able to project, but only for a little while.
实际上，舒尔茨所找到的这个方法，可以记录下阿哈桑所投影出来的影像，但却只能维持很短的时间。
Schultz's images disappeared soon after he had made them.
舒尔茨的影像技术，在他发明之后没多久就消失了。
It wasn't until 1839 that people figured out how to project images onto light-sensitive surfaces
一直到了1839年，才有人找到方法，能够让影像投影在对光敏感的物体表面，
that would retain the image after exposure, and thus, photography was born.
并且让影像在曝光后依然能够保留。自此，摄影技术诞生了。
At that point, it was mostly two inventors who fought for the best way to make photos.
在当时，有两位发明家竞相研发最好的摄影技术。
One was British scientist Henry Fox Talbot,
一位是英国科学家亨利·福克斯·塔尔博特，
whose calotype process used paper and allowed many copies to be made from a single negative.
他的卡罗式摄影法以纸张为材料，能够从单一的底片制作出多张相片。

The other inventor, Louis Daguerre, was an artist and chemist in France.
另一位发明家路易斯·达盖尔，是一位法国艺术家与化学家。
He developed something called a daguerreotype, which used a silvered plate and which produced a sharper image.
他发明的技术称之为银版摄影术，就是使用镀银的铜板来产生清晰的图像。
But the daguerreotype could only make positive images so copies had to be made by taking another photo.
但银版摄影只能产生正像，所以要复制照片时，只能再拍一次照片。
In the end, the daguerreotype won out as the first commercially successful photographic process
最后，银版摄影术胜出，成为史上第一个成功商业化的摄影技术，
mostly because the government made it freely available to the public.
主要是因为政府将技术免费提供给民众使用。
So now that photography was available, getting a picture of yourself would be a snap, right? Well, not exactly!
所以，现在有了摄影技术，拍照变得轻而易举了吗？好吧，并非如此！
This process still required a whole dark room at the location of the photograph, which was a big hassle.
在拍照的地方，整个过程仍然需要有暗箱，这会是个大麻烦。
Picture the early photographers lugging enormous trailers with all their equipment wherever they wanted to take a picture.
从图片可以看到，早期的摄影师必须拖着巨大的拖车，载着所有的设备，到他们想要拍照的地点。
Not only that, but the early processes had extremely long exposure times.
不只如此，早期的摄影技术需要特别长的曝光时间。
To get a good photo, you would have to stand perfectly still for up to two minutes!
如果你想要拍摄一张好照片，你必须静止不动两分钟的时间！
This led to development of inventions like the head holder,
这导致了一项像头部支撑架那样的特殊发明，
a wire frame that would hide behind you while supporting your head.
一个藏在你背后的金属架，用来支撑你的头。
It's also why you don't see people smiling in early photographs.
这就说明了为何在以前的照片中，里面的人都不会笑。
It's not that life was that bad, it was just hard to keep a steady grin for more than a few seconds,
这并不是因为当时的生活过得不好，而是要维持一个稳定的笑容好几秒钟是很困难的，
so people opted for a straight-faced look. And then George Eastman came along.
所以，大家只好面无表情的看着镜头。接着，轮到乔治·伊士曼登场了。
Eastman believed that everyone should have access to photography,
伊士曼认为，摄影应该普及到所有人，
and he spent many late nights mixing chemicals in his mother's kitchen to try to achieve a dry plate photographic process.
因此，他不眠不休好几个夜晚，在妈妈的厨房里混合各种化学物质，尝试着实现干版照相的过程。
This would allow exposed negatives to be stored and developed later at a more convenient place
这可以让感光之后的底片，可以送到更方便的地方去保存和冲洗，
instead of carting those dark rooms, necessary for wet plates, around.
以此代替用马车将储存湿版的暗箱拉来拉去。
After starting a business, which initially made dry plates,
伊士曼起初的摄影事业是使用干片，
Eastman eventually discovered plastic roll film that would fit in hand-held, inexpensive cameras.
后来，他发明了胶卷底片，这样就能用在手持、平价的相机上。
These cameras sold by the millions under the tag line, "You push the button, we do the rest."
这些相机总共卖了几百万台，当时打出的广告词是：你只要按下按钮，其余的交给我们！
While Eastman was largely responsible for making photography a universal pastime,
虽然在当时是由于伊士曼才让摄影变得普及，
even he could not have dreamed of the ways photography had since shaped the world.
但是就连他也想不到从那以后摄影型塑了这个世界。
It's now estimated that over 380 billion photographs are taken each year.
据估计，目前每年拍摄的照片总数超过3800亿张。
That's more photographs each day than were taken in the first hundred years after photography was invented. Say cheese!
也就是说，现在每一天增加的照片数量，比摄影术发明之后的100年内所拍的照片数量加起来还要多！笑一个！