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Refelctions greater than 1 and L*

P

Paco Rosso

Jan 1, 1970
0
CIELab L* is defined from Y and the Yw which is the Y of the "white".
BUT:
If I have specular reflections in a scene (not in a laboratory) this Yw
should be the Greater luminance in the scene, not the luminance of a
perfect diffuser ¿Isn't it?

By chance: I put in scene a white card as the reverse of the kodak gray
card. That is my "Yw"? Then all "specular" reflections will achieve a
L* 100. If the scene has no fluorescence, and there is no light source
on the frame, and only a uniform ligth is enlightneing the scene: If I
measure a tone and read 3 stops (photographically talking) or greater
than the read of the gray card I will have a reflectance greater than
1. So I supose I whould count the greater "usefull" luminance as "Yw".

¿What do you think about it?

--
/*--------------------------------------*/
Francisco Bernal Rosso
Luz-Color-Fotografía
Webpage at:
http://pacorosso.blogspot.com
http://pacorosso.fotopopular.com
http://www.geocities.com/pacorosso
http://www.fotoforum.net/socios/b/b_f/fotos.htm
http://www.michelle7.com/contributors/r/paco_rosso.htm
 
P

Paco Rosso

Jan 1, 1970
0
video guy - www.locoworks.com a formulé ce martes :
I think you need to buy an incident meter.

I have 2 incident meters. Gossen profisix and Gossen multisix.
No, seriously, it is not a problem of measurement, but of processing. I
try to understand L* in that cases when we have luminances greater than
2.45 steps over the 18% medium gray.


--
/*--------------------------------------*/
Francisco Bernal Rosso
Luz-Color-Fotografía
Webpage at:
http://pacorosso.blogspot.com
http://pacorosso.fotopopular.com
http://www.geocities.com/pacorosso
http://www.fotoforum.net/socios/b/b_f/fotos.htm
http://www.michelle7.com/contributors/r/paco_rosso.htm
 
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