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Discussion Starter · #1 ·
Temperatures>


Those folks that thought the LT150 appeared a tad blue out of the box in the white areas, you were right!

http://www.dilard.com/dilard/images/lt150/lt150temp.jpg


The temperature is not terrible, but it could be a bit more linear. If course, the brightest areas are the most noticable and on my unit, they did indeed run a bit to the blue.

Luminance (Gamma)s>


Here is a graph of the luminance output when the projector is in 'Natural 1' mode. It could use a little tweaky-tweak, but looks pretty good.

http://www.dilard.com/dilard/images/lt150/lt150lum.jpg


Color Capabilitiess>


The projector won't be able to do the deep, deep reds of a 3-chip DLP, but saving $25,000 in the price should make you feel better about that. There is plenty of saturation in the very slighty orange red, though.

http://www.dilard.com/dilard/images/lt150/lt150cie.jpg


I think that the biggest coloring concern is a deep green, which will come out a little on the pale side (towards yellow). The D-ILA has a green that is in the stratosphere due to the Xenon bulb.


I do understnad that some of these issues are not LT150 specific, but DLP specific. LCD projectors should be able to produce a somewhat more saturated green.


Anyway, enjoy the pictures! I probably won't have a chance to make any more for a little while, but I wanted to get these up while I could.


Mark




[This message has been edited by milori (edited 08-17-2001).]
 

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Quote:
I do understnad that some of these issues are not LT150 specific, but DLP specific.
Could please explain which issues you mean? I thought the color gamut, temperature and gamma were dependant on the lamp, color filters and firmware, not the technology?!?


Thanks for any insight you can share. http://www.avsforum.com/ubb/smile.gif


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Huck
 

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Mark,


Way cool. Thanks so much for posting this research!


Did you happen to plot the "Natural 2" gamma?



-- billy
 

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Mark,


Is it too early to tell yet if we can look forward to improvement in black level? Is it going to let you manipulate the bias voltage (or is that term used only with DILA)?


Bob


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~ The Sultan of Cheap ~


[This message has been edited by RobertWood (edited 08-17-2001).]
 

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Discussion Starter · #6 ·
Hi Guys,


Sorry for the hit-and-run, but I won't have too much more time to spend on this for a little while. Here are the answers to your questions, though.



Arrow,


I am using a pre-release version of Colorfacts for the data.



Huckster,


You're probably right that it could be the bulb technology and not the DLP technology that causes the slightly yellowish greens, but I don't have a Xenon arc lamp DLP (i.e. 3 chip DLP) to compare. I understand that most (all?) single-chip UHP DLPs exhibit similiar characteristics.



Billy,


I haven't done anything more than above ('Natural 1'). Maybe this weekend I can try Natural 2.



Bob,


I just got my LT150 cable yesterday. I don't know anything about if this thing is 'Tweakable'...yet...
 

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Neat Mark. I thought Color Facts was DILA exclusive. But I clearly didn't understand that part of what you do is projector independent.


--Les
 

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It may or may not make much of a difference, but the bulb assembly appears to have a filter on it that reflects purple, while the miiror itself seems to reflect a greenish tinge...

At least to my uncalibrated eyes...

apg
 

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Colorfacts is a general purpose projector profiling package. You can use it on any projector you like and it will find the colour primaries, colour temperature, greyscale linearity, and all sorts of good stuff!


Regards,


Kam Fung
 

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Discussion Starter · #10 ·
Hi Arrow,


Kam is correct, there is nothing D-ILA specific about Colorfacts.


Apg, Interesting observation! So, do you think that the electronics/wheel put out too much green, and then the optics/filter try to correct for it? I hadn't heard that before, but that would be interesting.
 

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Bob,

I believe Bias Voltage is specific to DILA, and maybe LCD, because it is voltage which determines the LCD transmissiveness (reflectiveness, in the case of DILA). I know you know DLP uses mirrors, and thus, I don't think this applies to them.


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David Mendicino
 

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I'm not shy. Those graphs look really cool. I have no idea what they mean.


What are some good links/books for the theory behind this stuff.


--Les
 

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Discussion Starter · #14 ·
Sorry, Arrow. I should have explained things a bit.


The first graph is the "Temperature Histogram" and displays how the grayscale tracks. Black is on the left, white is on the right, and grayscales are between them.


The goal of that graph is to get a flat line, right where the dotted line is displayed. Small errors are difficult to see by eye. This projector has a temperature that is low in the dark areas, but high in the bright areas.


In a nutshell, that means that darks images are a little too reddish and bright images are a little too bluish.


The second chart is the "Luminance Histogram", and follows the same basic pattern (black on the left, white on the right) except displays output luminance. This is mostly a function of the gamma settings in the projector.


The third chart displays a "gamut" of the colors that the projector can produce. Colors in the triangle are reproducible, and those outside the triangle are not. You can determine how closely a device adheres to standards (like NTSC) and find out where the projector will have difficulty producing accurate coloration (green, on this particular unit).


The best way to learn about this stuff is to read the Colorfacts manual <grin>.
 

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Interesting.


I noticed something odd during the Colour Decoder check with Avia. Running the disc in interlaced mode the colours seemed pretty good. However in progressive mode with the same test - the green colour was about 15% to low.


Perhaps this corrobrates what Mark's tests have shown.


Puzzled as to why green drops in progressive mode though.


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milori,

Was this test done with the color wheel white segment disabled? If not, then it probably should be, since the colors should be much better with this white segment disabled.


Thanks,

Ross.
 

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Discussion Starter · #18 ·
White segment was off.
 

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mark,


"The temperature is not terrible."


What are the temperaures at the low and high IRE's? It looks pretty bad to me, unless the range is only a few hundred degrees in either direction.


Thanks




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Noah
 
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