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Discussion Starter · #1 ·
I have been trying to calibrate my NEC LT150 for the best picture quality possible. I am currently using the natural2 gamma setting. I am currently using the Hoya filter, and clear segment mod. At the default settings under natural2, reds and fleshtones seem much too pink looking and colors oversaturated. Under "picture", I turned the color down a couple of notches to the left and bumped the hue a couple of notches to the right. Now reds look better (still not perfect), but yellows look pretty off (kinda greenish?). I really have no further way of adjusting. Is this the best color I can get? Does the solution lie in adjusting the white balance (ex. R brightness/contrast, G brightness/contrast, B brightness/contrast)?
 

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You must budget for either the Avia or Video Essentials DVDs. Use the disc to set up the black and white levels (brightness and contrast), saturation (colour), and phase (hue) correctly. Once this is done, then get to the more advanced white balance tweaking by searching for LT150 and white balance related threads on this forum. This topic has been well covered in the past.


Good luck.
 

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i used AVIA several times to adjust the settings on mine, and it's very frustrating. i can never get it close to perfect, only a rough aproximation.

and yes, i do go in and adjust the white balances, and then have to go back and adjust the other settings again.


my yellows have always tended to a greenish hue. when i try to get them closer to magenta, it really throws the other colors off.

i've learned to live with the greenish yellows, although it would be great to fix that, but that seems to be a major dillard-type investment which i'm not prepared to make at this time.


i did recently drop down the color and that has improved the image (w/out using avia to check the settings).


i think i may spend another hour or two trying to re-calibrate soon.


in any case, using avia did get me into the ballpark at least.

when i first got the pj, it seemed like i felt i had to optimlly adjust the settings for each movie, and then sometimes, w/in the same movie depending on the nature of the scene (outdoors sunlight, interior dark, interior light, etc)
 

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Discussion Starter · #5 ·
I was referring to the white balance of the LT150 itself. I have already calibrated brightness/contrast/color/hue using Avia. But like I said, the red looks ever so slightly off, and the yellow is pretty unacceptable. When I search for "lt150 white balance" under "Digital Projectors - Under $5000 USD MSRP" it comes up with nothing. Could you point me in the direction of some good threads? Thanks!
 

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David - I was referring to the controls on the projector itself. Of course, if one is using the LT-150 with an HTPC, some adjustments can be performed at the source end, while others can be done at the display end. If one is using multiple inputs on the 150, it probably makes sense to set the projector to defaults and adjust stuff at each source if possible. If only one source is used, then it is up to you to see which adjustments work better for you. I use my 150 with an RP-56, and so do all the tweaking at the projector end. I should re-phrase that 'do' to 'did'. I haven't touched the 150's controls in ages. I have been in video nirvana for quite a while now.


We have discussed the use of the 150's white balance controls in quite a bit of detail in the past and I do not want to repeat myself (they were long and detailed posts). After doing the colour wheel mod, and using an FL-D or CC-20R filter, the white balance controls must be set to maximise the dynamic range of the projector. This is done by setting R, G, and B bias (or brightness) at a level such that when a low voltage (~5 IRE) signal is sent to the projector, one can see the faintest hint of that signal being projected on the screen. Thus no useful portion of the video signal just above black is clipped and shown as black - often referred to as crushed blacks. This ensures full reproduction of low level detail. In a similar fashion, the R, G, and B gain (or contrast) levels are set such that high level signals are reproduced at maximum output without clipping the top end which can result in crushed whites. Avia, with its moving black and white bars is perfect for checking clipping with digital projectors.


Once this is done, the LT150 is operating optimally. Where we got lucky is that with the 150, the combination of:


1. colour wheel design (it has colour segments of unequal lengths);

2. UHP bulb spectrum (strongly biased towards blue-green);

3. optics, firmware etc. (NEC designed a good one here);

4. FL-D or CC-R filter (thanks to Guy Kuo's work); and,

5. max'ing dynamic range using white balance controls;


produces a nice and even gray scale that is still a tad blue, but nowhere as cool as it is out of the box. Reds are beautiful (the rose petals in American Beauty are a good test) and yellow looks like the skin of a lemon (on my setup anyway). The added bonus of the colour wheel mod is that now absolute black becomes darker by about 30%. This lets low level detail stand out even more prominently, in effect increasing the low level contrast of this projector. Add a high-power screen and the colours take on unbelievable punch.


Colchak, I am surprised you are having difficulty with Avia and the 150. I found setup to be very straightforward and simple, and the results were very good. This is even before I mod'ed the projector and started playing around with filters and white balance.


Jeff, with the forum reorganization, I am not sure how old threads are archived any more. You may want to look at posts by me relating to white balance, and also by Guy Kuo on the same topic. This will take you to the right threads where quite a few other LT150 stalwarts have posted their methods/experiences.
 

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I also had trouble setting up the LT-150 with the pulse needle patterns in Avia. Especially with the blue filter, it seemed rather abritrary where I ended up since no matter how far I pushed the levels in either direction, the needle was never highly visable. I often found myself saying "that might be it or it could be my imagination".


Also my eyes got tired squinting through the plastic strip. Could the PJ be adjusted by taping the colored plastic over the lens? That might make it easier.


Any tips folks have on using AVIA correctly would be appreciated. The website does not provide much details and neither it nor Video Essentials seems to have detailed enough instructions. A pdf. file that you could pull from the DVD or website would be an added benefit (hint - hint, Guy I know your out there).
 

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The only place in Avia where the coloured film strips are required is when one is adjusting saturation (colour) and phase (hue). In an advanced case, the coloured strips come in handy when setting the levels of R, G, and B gain in the white balance controls.


Why would you be using the blue strip with the needle pulse pattern anyway? The needle pulse pattern is used for setting white level (contrast) and does not involve any colour adjustments.


Avia has detailed help screens which explain how and which pattern to use the film strips with.
 

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Question on LT150 calibration:

Should I do the black and white level calibration, and white balance with the FLD filter on, or install it afterwards?

thanks,

Jose
 
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