Comments on: Malaysian nibbles http://www.ronanpalliser.ie/blog/2009/11/11/malaysian-nibbles/ A regularly-updated blog of a photographer in Dublin, Ireland Wed, 08 Feb 2012 12:38:40 +0000 hourly 1 http://wordpress.org/?v=3.2.1 By: Ronan Palliser http://www.ronanpalliser.ie/blog/2009/11/11/malaysian-nibbles/comment-page-1/#comment-126 Ronan Palliser Wed, 11 Nov 2009 19:08:15 +0000 http://www.ronanpalliser.ie/blog/?p=2162#comment-126 Thank you JC - that makes a lot more sense. I knew there was something off with my interpretations of the colours, but couldn't tie it down. The yellow shadow being from daylight makes total sense - i.e. the yellow is due to the tungsten or candle light which can light part of the daylight sources shadow. That's the key element I wasn't considering. So the sources are correct, but the daylight source is above the subject and to the left, the smaller tungsten/candles source is above but behind the dish. Thanks for the clarification and for directing me to your image. I'm going to refer readers to your comment. Thank you JC – that makes a lot more sense. I knew there was something off with my interpretations of the colours, but couldn’t tie it down. The yellow shadow being from daylight makes total sense – i.e. the yellow is due to the tungsten or candle light which can light part of the daylight sources shadow. That’s the key element I wasn’t considering. So the sources are correct, but the daylight source is above the subject and to the left, the smaller tungsten/candles source is above but behind the dish. Thanks for the clarification and for directing me to your image. I’m going to refer readers to your comment.

]]> By: JC Dill http://www.ronanpalliser.ie/blog/2009/11/11/malaysian-nibbles/comment-page-1/#comment-125 JC Dill Wed, 11 Nov 2009 17:36:37 +0000 http://www.ronanpalliser.ie/blog/?p=2162#comment-125 I think you have the light sources backwards. The color of light in a shadow reveals and informs us of the source of the light that falls in the shadowed area. The yellow colored shadow's *light* comes from an incandescent or candle light source (a yellow light source) and the reason this shadow is yellow is because it's the shadow of the daylight light source, none of the bluer daylight falls in this area. The daylight is blocked, the incandescent or candle light fills the shadow, so the shadow is yellow. The bright specular reflection in the red dish shows us the direction of the daylight source. Because of the soft edges of the yellow shadow the daylight source is a "wide" source such as a window or skylight admitting blue "bright sky" light into the room. The shadow is in 2 colors because the incandescent light is filling part of the shadow with yellow light. The areas where the incandescent light is also blocked the shadow is dark red. This has a hard edge, which indicates that the yellow light (the blocked light) is coming from a small light source such as a bare light bulb. The shadow lines up almost exactly with the rim of the dish, indicating that the light source is overhead, and directly behind the dish, such as an overhead light fixture ~10 feet up and ~20 feet behind the dish. I learned this in a colored lighting exercise in a lighting class. See: http://portfolio.jcdill.com/2008/December-2008-1/7085093_NoLTw#454131493_rTH8B The figure is chrome. It clearly shows the colors of the light - blue on the left, magenta on the right. The figure is standing on yellow paper. The green shadow is from the blue light hitting the paper (blue + yellow = green), and the magenta light is blocked by the figure. The red shadow is showing the magenta light falling on the yellow paper (magenta + yellow = red), and the blue light is blocked by the figure. The green shadow is caused by the magenta light, and the red shadow is caused by the blue light. I think you have the light sources backwards. The color of light in a shadow reveals and informs us of the source of the light that falls in the shadowed area.

The yellow colored shadow’s *light* comes from an incandescent or candle light source (a yellow light source) and the reason this shadow is yellow is because it’s the shadow of the daylight light source, none of the bluer daylight falls in this area. The daylight is blocked, the incandescent or candle light fills the shadow, so the shadow is yellow. The bright specular reflection in the red dish shows us the direction of the daylight source. Because of the soft edges of the yellow shadow the daylight source is a “wide” source such as a window or skylight admitting blue “bright sky” light into the room.

The shadow is in 2 colors because the incandescent light is filling part of the shadow with yellow light. The areas where the incandescent light is also blocked the shadow is dark red. This has a hard edge, which indicates that the yellow light (the blocked light) is coming from a small light source such as a bare light bulb. The shadow lines up almost exactly with the rim of the dish, indicating that the light source is overhead, and directly behind the dish, such as an overhead light fixture ~10 feet up and ~20 feet behind the dish.

I learned this in a colored lighting exercise in a lighting class. See:

http://portfolio.jcdill.com/2008/December-2008-1/7085093_NoLTw#454131493_rTH8B

The figure is chrome. It clearly shows the colors of the light – blue on the left, magenta on the right. The figure is standing on yellow paper. The green shadow is from the blue light hitting the paper (blue + yellow = green), and the magenta light is blocked by the figure. The red shadow is showing the magenta light falling on the yellow paper (magenta + yellow = red), and the blue light is blocked by the figure.

The green shadow is caused by the magenta light, and the red shadow is caused by the blue light.

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