positionForPages[18]={page:18,positions:[{w:"达盖尔银版照相法是利用镀有碘化银的钢板在暗箱里进行曝光，然后以水银",p:[0.068350,0.826451,0.893375,0.826451,0.893375,0.781962,0.068350,0.781962,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025025]},{w:"蒸汽进行显影，再以普通食盐定影，得到的实际上是一个金属负像，但十分",p:[0.068350,0.879822,0.893350,0.879822,0.893350,0.835378,0.068350,0.835378,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000]},{w:"清晰而且可以永久保存。由于曝光大约需要",p:[0.068350,0.933156,0.543350,0.933156,0.543350,0.888711,0.068350,0.888711,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000]},{w:"20",p:[0.555896,0.933156,0.580896,0.933156,0.580896,0.888711,0.555896,0.888711,0.012500,0.012500]},{w:"到",p:[0.580896,0.933156,0.605896,0.933156,0.605896,0.888711,0.580896,0.888711,0.025000]},{w:"30",p:[0.618427,0.933156,0.643427,0.933156,0.643427,0.888711,0.618427,0.888711,0.012500,0.012500]},{w:"分钟，因此，早期摄影",p:[0.643427,0.933156,0.893427,0.933156,0.893427,0.888711,0.643427,0.888711,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000]},{w:"多拍摄静物、风光、人像等等。这是达盖尔的银版摄影作品《静物》。",p:[0.068350,0.986489,0.843427,0.986489,0.843427,0.942044,0.068350,0.942044,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025000,0.025077,0.025000,0.025000,0.025000,0.025000,0.025000]}]};