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	Light Illusion Forums / Display Calibration /
	Question about Meter Matching and profiling from the lens

	airscapes ZRO	#1 \| Posted: 19 May 2023 12:17
		When taking readings from the lens of a projector, and matching that to reading off the screen taken on a spectro, would there be any detrimental performance or outcome in applying the match while a full cube profile is being created off the lens? Not sure how popular this process is, but it was outlined by someone on avs and it worked quite well for me. Just not sure if I should apply the match while profiling or wait and apply after the readings have been taken. I really like the fact that either works! I guess the only advantage of taking the profile readings with the match enabled is that the luminous reads would be recalculated and look more normal if viewed live Thanks. Doug CS HTL, i1pro, C6, PG, Runco Q750, HP 2.8 target 709 2.2 Q750i/Planar 8150 /HP 2.8

	Steve INF	#2 \| Posted: 19 May 2023 12:26
		There is no difference at all when the Probe Match is applied, other than if set before taking measurements, the values shown are immediately with the match applied... But, we never recommend profiling form the lens. The screen is a very large part of the image colourimetry. Also, as the match would be a huge variation/change in values, you would likely get greater inaccurate readings... Steve Steve Shaw Mob Boss at Light Illusion

	airscapes ZRO	#3 \| Posted: 19 May 2023 13:48
		Yes, I can understand that, however, the increase in light at the low end makes for a much faster, more accurate readings, and a better outcome in gray scale and gamma. The idea is the matching from the screen deals with the major color shift of the screen. I am also using measuring devices from 2011 so they are probably not the most accurate and sensitive and of course the projector is from the same era with low output on a high gain screen that shirts red off axis. The room is far optimal (living room not light tight during the day) so the cube must complete in the time available and reading from the lens did just that. It is never going to be perfect but with the eecolor box and the LUT from CS it looks WAY better than it does without!! Thanks for the fast response! Doug Q750i/Planar 8150 /HP 2.8

	Steve INF	#4 \| Posted: 19 May 2023 14:47
		if you are looking just match the colorimetry, when you do the probe match with the probe pointed at the screen, manually edit the Y Luma values to be the same as when reding from the lens. That way there will be less aggressive probe matching being applied - as only the chroma will be being matched. When generating the LUT, the actual Luma value are not relevant, as they are normalised. Steve Steve Shaw Mob Boss at Light Illusion

	airscapes ZRO	#5 \| Posted: 19 May 2023 20:41
		So once I get the lens facing meter set up and get the reading from that, manually edit the white luminance reading within the screen read data, putting in the high number from the lens read of the white only? Leave the luminance readings of rgb alone? I am not quite sure where that is done, but if I remember a window comes up when doing the match and I assume once the readings are done I can access that data to change it? Or do you mean to find the saved file and edit it directly? Sorry not experienced enough to know but I understand why I am doing it. Doug Q750i/Planar 8150 /HP 2.8

	Steve INF	#6 \| Posted: 20 May 2023 10:15
		You need to edit the value used in the Reference probe data, not the Active. Just edit the Y values to match the Active Probe. Steve Steve Shaw Mob Boss at Light Illusion

	airscapes ZRO	#7 \| Posted: 20 May 2023 13:05
		Not trying to be difficult, but as an example, this is the data in the reference file from last time. I assume I am just changing the white entry in the "L" line, looks like the Luminous reading. What about RGB values in that same line, would they not also need to be changed to match? Thanks, Doug <?xml version="1.0" encoding="UTF-8" ?> <builder_color_space name="[351165] i1proruncoFacingScreen" version="2"> <head> <x red="0.636421" green="0.306464" blue="0.148563" white="0.315679" /> <y red="0.329207" green="0.594352" blue="0.063841" white="0.333378" /> <L red="24.9936" green="88.0595" blue="9.61695" white="123.136" /> <gamma>1.000000</gamma> </head> </builder_color_space> Q750i/Planar 8150 /HP 2.8

Steve

INF

#8 | Posted: 20 May 2023 13:11

Sorry - you actually need to edit all the Y values for RGBW in the Probe match window for the Reference probe.
Make them the same as the Active Probe values, so only the xy values are different.
You can edit then in the Probe Match window directly, as per this example!

Steve

Edit Values

Steve Shaw
Mob Boss at Light Illusion

	airscapes ZRO	#9 \| Posted: 20 May 2023 13:21
		Thanks, that makes sense and I assumed that was the case but wanted to make sure Have great weekend and thanks for the quick response on a Saturday! Doug Q750i/Planar 8150 /HP 2.8

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	Light Illusion Forums / Display Calibration /
	Question about Meter Matching and profiling from the lens

Question about Meter Matching and profiling from the lens