裡面提到的三原色天然寫真印畫法
可能是指這個
http://www.loc.gov/exhibits/empire/making.html

We know that Prokudin-Gorskii intended his photographic images to be viewed
in color because he developed an ingenious photographic technique in order
for these images to be captured in black and white on glass plate negatives,
using red, green and blue filters. He then presented these images in color in
slide lectures using a light-projection system [right] involving the same
three filters.

這位老兄特製了一台三合一相機. 可以一次拍三張塗有感光劑的玻璃片
這個拍出來是黑白負片

他在三個鏡頭前面分別加上R.G.B濾鏡. 如此等於得到同一張影像的R.G.B三色色板

然後放像時再套色上去. 就得到了彩色照片


等於是最早的彩色照相分色製版
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