Friday, April 28, 2006

20060428 Practice of Color to B/W

晚上錢得樂突然問我彩色轉黑白的經驗,傳給我這個網頁 ─ 耀輝的旅行與攝影筆記上「一種彩色轉黑白的方法」。我反正上網無聊,也隨便找一張圖來試試 :P

這是原圖:



直接去飽和 ─ 效果不錯,但左側的叮咚橋招牌黑掉了:



使用 Photoshop CS2 的 Grayscale 功能 ─ 叮咚橋回來了,亮部也比上一張更亮些:



色彩空間轉成 Lab,取 L channel ─ 用在這張圖上顯得太亮了:



使用 Channel Mixer [R+30, G-20, B+30] ─ 廟顯得很平:



使用 Channel Mixer [R+85, G+30, B-40] ─ 減去藍色頻道的值之後,天空顯得黑多了,屋簷突起部和凹下的地方反差很大,整張看來不太自然:



20D 因為有內建黑白功能,也提供了許多數位彩色濾鏡可套用,所以要拍黑白照片很簡單,不過要處理好就比較麻煩了。一般要作得好的話,數位彩色濾鏡的使用會是一個重點,主要是利用某種色的濾鏡只允許該色通過的原理,來加深(變黑)或淡化(變白)照片裡的色彩元素,達到突顯主題的效果。

另一方面,20D 因為感光度可支援到 ISO 3200 的關係,拍彩色照片時或許雜訊太多不好使用,但用在黑白照片上卻可能因為粗粒子的加入讓影像效果有另一種變化,這也算是雜訊的廢物利用吧 :P

Mobile01 上也有一篇關於色彩濾鏡在黑白照片的使用文章:
[老舊知識〕黑白攝影用的濾鏡(增加及修正部份資料)

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