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Discussion Starter · #1 ·
Gentlemen ,


I've formely used my Toshiba RPTV 40" 16:9 which has been ISFed ( very natural and beautiful color , red which is red ...) to adjust my preset color temperature GAIN on a 4000 hours SONY 1252 . I've fed my Tosh 5109 DVD player to both my projector and my RPTV at the same time with The Fith Element and The BEE GEES One night Live . I eyeballed to correct the color of my projector and the results are very rewarding , both look almost identical now . The values of GAIN are R 125 , G 95 , B 120 . I didn't touch my BIAS values , I guess they were default factory values and are almost identical between 140 and 150 for R , G and B .


Recently a friend of mine used those numbers on his recently purchased 1600 hours 1271 , and the results are more than expected : beautiful and identical colors on his 1271 like on my 1252 .


So 2 conclusions :


1- The 1252 and the 1271 must have the same factory G2 adjustments .


2- If you have not tinkered with your G2 adjustments , you just save yourself an ISF calibration with those numbers !


Enjoy your ISF Sony 12XX .


N.Nguyen
 

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Oh you are sly. The Optical Comparator is used principally in the same manner to set the gray scale. While viewing the displayed image through the device you compare it to the calibrated light source displayed in the device. However the settings that you recommend would not be consistent across the 12XX series. There are many other factors to consider, for example tube wear, power supply output, and signal source just to name a few.
 

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Discussion Starter · #3 ·
Tim ,


Your remarks show indeed your knowledges of the subject . In my 'enthusiastic rush' to post the 'announcement' , I didn't include the usual ubiquitous YMMV but the colors of the the Fith Element movie I saw with the 1271 ( with a different DVD player ) are as close as you can get , for normal working condition 12XX ( not too much tube wear , power suplly in normal condition...) , to an ISF picture without having to pay for a calibration !


Regards ,


N.Nguyen
 

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Mr Nguyen,


It's easy enough for owners of 127x series projectors to record their current values for Bias and Gain and then try your numbers to see what they think.


I guess your idea is that if the projector is fed a accurate source such as NTSC accurate standalone player (is there such a thing?) or a O-scope verified NTSC accurate video output from a HTPC, and the G2 are set at factory presets, and the tubes are relatively free of wear, then the same numbers for Bias and Gain should produce the same results. One serious flaw with that approach is the variance of screens. Since these projectors are used in conjunction with a screen that should be part of the equation. I've seen tests of screen material and the colors and their associated prominence vary from one screen to the next.


It's interesting at least that your not specific about Bias, Brightness and Contrast. Since these all effect the greyscale directly. I've found Bias to be more critical for greyscale tuning than Gain.


Thanks and Good Luck,


Brian



Edit: The other thing I forgot to add is although I've never had a visit from an ISF technician (apart from a short social visit from Mr. Chuck Williams) it seems unlikely that the ISF calibration would only involve Bias and Gain adjustments. In the least, an ISF technician would insure your focus and optics were not somehow mis-adjusted and would also accurately set you black and white level. In the best of cases you would chose an ISF technician with experience with your particular machine who could spend more time tuning it to a top level of performance.
 

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Discussion Starter · #5 ·
Mr Hampton ,


Thank you for sharing your valuable thoughts on the subject .


When I started about 2 years ago to be involved in this HT hobby, after a certain time , considering the amount involved , I decide not too easily though ( for me anyway ) , to get my HD RPTV ISFed by a very competent ISF tech in Montreal , pretty flat 6500 K curve from 10 to 90 IRE and a little bit raised in the extreme ends. Actually it was a full blown calibration : geometry, focus ,convergence ... and also with the grey scale calibration , the only ISF recommended calibration . And the real improvement I could see is in the color rendition , the other improvements in clarity, sharpness , 3 dimensionnality , more detail in dark scenes... are more or less debatable , at least on my set ( actually some people are disappointed after having their set ISFed , pictures are darker, less sharp ... ) . When I got my 1252 , of course after a good setup , focus ( did not do the astigmatism yet ), convergence , geometry ...without much effort I was able to get the real important improvement ( the balance of colors ) when you get your projector ISFed . Even if I'm in scientific fields with a few engineering degrees and being in Mid and Hi-end audio , I'm more of a " the proof is in the pudding " , " what you hear and what you see is what you get " type . And yes I can tell you that the colors are right on after living 2 years with an ISFed set . And I only thought if more people can benefit , it's money well spent.


About the screen , I've calibrated the colors firstly on a Draper 2500 , then use now a DaLite Hi Power ( which I really love despite all what a lot of people can say like hotspotting, I never saw anything like it on my screen , yes the view angle is narrow , but I sit right in the middle of the screen ! and I can

also lowered down a lot my contrast ) and my friends' screen is a home made low gain screen from Home Depot material. And within human detectable viariations , all I can say is the colors are more than less the same on those 3 screens, what can I tell you more ? Ok if you measured them they may not be exactly the same , but I can only see with my eyes !


Now about the BIAS , I did'nt touch it , did'nt even bother to mark them down , but they are in the 140-150 range , which are pretty much the same thing . The brightness is 45 and the contrast is , well variable . When I use the Gain R125 G95 B120 , the contrast is 60 , now I double up the Gain R250 G190 B240 and the contrast is only 30 now but this contrast setting depends on how bright you like your pictures but doesn't , at least to my eyes , change the balance of the colors , which I think this whole ISF business is about .


Regards,


N.Nguyen
 

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N.Nguyen,

Thank you for posting this information. While it is good to heed the advice that Brian Hampton provides, I think it is great to post this kind of information. I will try these values on my Sony 1252 (w/ a Dalite HiPower screen just like you) and see if it improves the picture from the values that I already have.
 

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Hello All


It's nice to share info but it's totally useless

I calibrate a couple of the Sony 12XX series and never came with the same numbers

You should check this by reset the 6500 to factory default and show the settings here and compare this with others

You will see that they are different


Rob
 
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