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| The Digital Darkroom The In-Computer editing forum. |
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#1
30-10-06, 12:41
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Optical illusion
Spehen's Flower shot comments reminded me of this link.
An Interesting effect. http://bobatkins.com/photography/tec..._illusion.html
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Rob ----------------------------------------------------- Solar powered Box Brownie Mk2 Captain Sunshine, to be such a man as he, and walk so pure between the earth and the sea. WPF Gallery Birdforum Gallery Last edited by robski; 30-10-06 at 13:11. 
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#2
30-10-06, 12:58
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Very interesting - you cannot believe your eyes!!
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http://www.aviation-photography.co.uk/
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#3
30-10-06, 13:05
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That was fascinating, thanks for the link robski.
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Christine Iwancz Gallery upload limit is 4 photos per 24hrs Gallery Posting Guidelines here http://ciphotography.freehostia.com/index.php Equipment= Canon 7D, 40D, 400 f5.6, 75-300, 100mm Macro, 18-55, Canon 70-200 f4, Tokina 12-24mm, Kenko pro 300 1.4,1.5 and 2.0x, Jessops ext tube set, Canon 580 flash. Home made ring flash. . Close-lens.
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#4
30-10-06, 17:59
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Wonderful link. Thanks Rob.
BTW I am not at all surprise. I learned very well about the eyes illusion and the kind of moron I am long back dating back to the time I married my beloved wife. Good she is not reading this or if she does, Honey my account is been hacked...
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S a s s a n . ------------------------------ "No one is going to take our democracy away from us. Not now, not ever. " JOE BIDEN
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#5
31-10-06, 18:48
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hate to be a spoilsport, but only the dark squares in no shadow and light ones in FULL SHADOW are 120/120/120. The light ones are otherwise 206/206/206. The dark ones in shadow are 62/62/62. Also a thicker 120/120/120 bar only matches the dark squares as expected. The illusion ONLY applies to squares A & B and other light squares in full shadow, ie it amounts to a visual underestimation of the degree of shade. A selection 120/120/120 copied to the edge of shade sticks out.
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#6
05-11-06, 17:40
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Quote:
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#7
06-11-06, 03:16
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Quote:
__________________
S a s s a n . ------------------------------ "No one is going to take our democracy away from us. Not now, not ever. " JOE BIDEN
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#8
06-11-06, 10:12
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This is about visual perception of luminance, which to the eye is comparative, ie takes account of the lighter or darker background around a specific patch of the picture. The computer on the other hand measures the absolute values, which I have recorded above.
You can get do an equivalent simple exercise on human perceptions of heat compared to thermometer readings by filling 2 bowls of water with cool and fairly hot water. Dipping your hands in in different sequences gives you a very different impression of the temperatures of the 2 bowls than if you stuck a thermometer in. BTW no spelling mistakes as I am taking notice of FF2 underlines. Try the counter-intuitive approach that solved my FF problem ie if you want the spell-checker ON, TURN IT OFF, quit and restart. Now turn it on & next time it may work.
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