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Barco Colour Calibration

Discussion in 'Projectors' started by Alaric, Apr 26, 2006.

  1. Alaric

    Alaric Member

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    Hi There,

    Got a Spyder2 Express today via ebay for really very little cash (£70ish). The bundled software isn't much cop for HT use, but it works with my old Optical and can get the colour info window up and even works with an automation script from AVS. Made a tripod holder via a DVD case, though different in design to the rest as i found one that was smooth and cut a central hole for the censor and used the suckers !

    So i've just been through a black to 100 IRE sweep on Avia and my colour is aparently high 7-8000 for the inbuilt 6500 setting.

    A surgested starting point is 20 IRE and tweaking for x,y of 3.13,3.30 which i've done by increasing red to increase x and decreasing blue to increase y, via my Barcos Red/Blue Gain controls under white balence.

    What do the Red/Blue cut off controls under black balence do ??

    Oh and any tips ???

    Ta,
    Lee
  2. Mad Mr H

    Mad Mr H Member

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    Please post a picture of the test kit you have.........

    Do you use a HTPC?

    Is it not best to try and use the gamma curve to correct things....

    Not sure about all pcs but mine can do individual colours.....just an idea.

    My colourimeter has not seen daylight since I bought it! Or any other kind of light :D


    The black level cut off are for content in an all black screen, I thought the others were for all white.... so a very low and high ire to set those 2.

    PM Garry lightfoot - he is often seen posting about these things.........(And will put me right :rolleyes: )
  3. Godfather

    Godfather Member

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    IIRC you should use a 30IRE field to adjust the blue and red cut offs, and a 70IRE to do the gains. Doing one will affect the other so you'll need to go back and fine tune. Gary is definitely the man to speak to!
  4. Alaric

    Alaric Member

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    Hi,

    Mad - Yep run a HTPC anyway, so computer based analysis is easy for me. I'll try and take a couple of pics tonight. The hardware is a Colorvision Spyder2 which is supposed to be the best for low money. I bought the Express package and use Optical from a previous version and it works fine so is a cheap hardware upgrade if you have the software. The Express software itself is useless for HT use.

    You are supposed to calibrate the PJ to reasonable accuracy before tweaking the HTPC output. I don't know if setting from a standard DVD player would be better than the HTPC output as if your initial HTPC set-up is flawed, then again, how many reasonable stand alone players produce reference levels ?

    I recall trying to set the grey balance by eye on my old BD800 and found that hard, every tweak towards one colour made a colour shift elsewhere, so I've been looking for a measurable method for a while.

    I am curious if there is a post calibration visual check, IE like the colour decoder check in AVIA with the filters or something ? As i would like verification that the meter is working accurately for my system rather than just having blind faith.

    God - Ah, yes, i recall something aeon's ago about that, however the brief instructions i was reading said about IRE 20 and starting there, they only referred to gains, but then i think the guy had a DLP/LCD matchbox.

    I guess once I'm done and happy i should post details of how etc on my web site as i haven't seen reference to a Barco PJ in respects to Spyder2 Calibration.

    Cya,
    Lee
  5. Mr.D

    Mr.D Active Member

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    You adjust the RGB cuts for the lower end of the intensity range 20-30% (IRE) is about right.

    You adjust the gains for the upper end 70-80%.

    They will interact with each other so you have to ping pong back and forth between each until you can make no more improvement to either.

    You should use rader's spreadsheet off the AVS forums to model gamma , this will give you an idea of how best to set Y intensity at each point (adjusting the RGB controls will change intensity in addition to colour). A good starting place is to note the initial Y value at the cut and gain adjustment point ( 20 and 80 for example) and ensure that after adjusting for colour balance you restore the Y to its original value ( adjusting all the RGB settings by the same amounts in a perfect world would vary Y and leave the actual balance alone (x,y) , however you will find you have to readjust the colour balance as you increase the overall intensity.

    Additionally especially on a CRT its best to drop values to balance the colour rather than up them , this way you'll ensure you are not needlessly correcting one overdriven gun with another . Once the balance is achieved adjust for intensity.

    Post calibration check: verify the balck and white point are still correct , readjust if necessary, recheck colour and tint. grayscale ramp will give you indication of any grayscale tracking errors. The deltaE model in rader's spreadsheet gives a good indication as to the visibility of any remaining inaccuracy (below 3 is considered acceptable)
  6. Alaric

    Alaric Member

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    Hi There,

    I think thats the spreadsheet i am using, Has tabs for Avia/DVE/Getgrey + instructions and a HDTV/NTSC/PAL set of tabs yes ???

    Slamming the numbers in from Avia produces some pretty graphs in the initial tabs, but it seems to lack the idiots guide that i seem to require.

    I'm going to try Using 30 IRE and nudging the black cut offs for red/blue and then using the 70 IRE patern and the red/black gains and then re-evaluate the numbers in the spreadsheet.

    I don't know quite how you use the latter HDTV/NTSC/PAL colour part, i guess there are other paterns on the discs for these that you measure against.

    Y is lux or light output yes ??? If so what do you adjust to increase decrease this directly, or is it effectly part of the brightness/contrast pair ?

    Feeding the BARCO PJ RGBHV (port 3 now for HTPC) i have no user adjustment capability for colour/tint as IIRC RGB are pure and hence don't require cut/boost to compensate for gain/loss that happens with composite/s-video. I can however tweak the source (HTPC) later to make any fine adjustments.

    Due to much fiddling with barco's i'm already used to the iterative nature of the beast and that after doing this it will probably affect the contrast/brightness which will in turn affect the gray balence, which will affect....

    One day, if i'm really lucky, i may get to watch a film :eek:

    cya,
    Lee
  7. Mad Mr H

    Mad Mr H Member

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    For those reading this G2 should be set first I guess.

    HOWEVER - many PJ's have had "little fingers" in them and set the actual G2 cablibration point might be wrong within the PJ - the 800/801 series are VERY easy to mess that up.....

    If you G2 set then test the entire range a gun over/under on the entire range can then be G2 corrected, followed by high low points, followed by even more acurate intermediate points....

    A have not looked into this yet, BUT have considered a copy of Avia pro......Someone mentioned that the ire settings were wrong in it though so I held back for now......

    Once you have done this PLEASE set up a complete post about it and all you find, this will make a great FAQ post and of great help to all.......
  8. Mr.D

    Mr.D Active Member

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    The colour standards just effect what primaries you are aiming for and the graphs reflect those aims. Although you might need to raise black point beyond normal viewing setting to get it to read correctly on the sensor ( this isn't a problem just drop it back to normal after the cal)

    Y is intensity (sometimes innacurately referred to as luminance) lux is just a unit of measurement. I actually prefer foot lamberts. When you adjust the RGB controls you don'; just effect colour , if you drop blue it doesn't just push the colour towards green and red it also drops Y . Y is a function of RGB values.

    To adjust Y you have to adjust the individual RGB settings "equally" although you will find the effect of each colour is unequal , green will likely efefct Y more than red and even more than blue, ie an increment of green is worth more Y than an increment of red. So when you "gang" them all together (some displays even have a specific control to do this "All cuts" "All gains") you will likely have to readjust even when you increment tham all by the same amount.

    This is the primary reason to use the rader spreadsheet for modelling gamma. It will give you an indication as to whether Y is too high or too low at your adjustment points.

    Ensure you have black point and white point correctly set before you adjust colour temp. (although you may have to raise black point to allow the meter to read it more accurately , just reset it after the cal)
  9. Alaric

    Alaric Member

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    Hi There,

    Mad - Its a BG808, the G2 setting was done first, particularly after my Red gun amp died (see other thread). I also look into the lenses and check that the tube looks a resonable intensity as per Rolands old instructions.

    I have Consumer Avia, VE and DVE. For the colour balence i'm using Avia and an 11 step black+ IRE 10-100 paterns that i've bookmarked in PowerDVD. I normaly use TT, but the aspect seems wierd with Avia and PowerDVD's bookmarks make things easier to locate. I'd love to see getgrey with a CRT bias, but it says specificaly that its non CRT friendly :(
    Personaly i'd pref to use a PC generated patern but non of the speadsheets alow this and converting one is posibly beyond my colourspace knowledge.

    D - The barco doesn't have a user based green gain/cut control to my knowledge. I see that a colour gain will increase light output, a very Doh thats blindly obvious momemnt !

    Gamma i've yet to get my head round, i just recall it from old doom/quake days where you upped the gamma to see the background and make gameplay easier. I guess from that its another function of light output and shadow detail, though i thought contrast/brightness would effectivly adjust that ???

    cya,
    Lee
  10. Mr.D

    Mr.D Active Member

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    You can adjust chromaticy with red and blue ( dropping blue will increase y as well as x , red will mainly effect x just ensure your white point is healthy before doing the cal , adjust blue to get y sorted out and then adjust x with red , there will be a little interaction).

    Gamma is an oversimplification of the intensity curve of your crt. If you have little knowledge of gamma do some research first (its actually very simple when you cut through all the over complication). If you ensure you somewhat match the intensity back at each adjustment point you won't have significantly effected it during the calibration anyway.
  11. Alaric

    Alaric Member

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    Hi There,

    OK. Just done a first try by adjusting the R/B cut-offs at 30IRE & the R/B gains at 70 IRE.

    My first worrying thing is the Blue cut-off is 0 !

    After running another 11point check and dumping the numbers into the spreadsheet (colorimeter007.xls) i see that from before my colour temp was 7017-8381 and now it is 5800-7300 and my gamma is 2.07 to 1.98, which is technicaly worse for 2.2 !

    I would also say on looking at white fields there is a red push, but that may be my eyes.

    I think i'm going to try again with TT as maybe its something to do with my calibration of that player versus powerDVD.

    cya,
    Lee
  12. Mr.D

    Mr.D Active Member

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    investigate your black point and G2.
  13. Alaric

    Alaric Member

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    Hi There,

    Ok....Whats the black point on the Barco BG808 then, ie how do i set it ???

    I'm fairly certain the G2 is reasonably good, well as good as it gets twisting a fast moving pot while contorting yourself to look in the tubes.

    Any way of measuring the G2 with the spyder gizmo or similar ???

    Ta,
    Lee
  14. Mr.D

    Mr.D Active Member

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    Look mate I really think you should do a bit of research before you mess about with your CRT any more.
  15. Alaric

    Alaric Member

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    Hi There,

    I personaly find that comment along the lines of offensive and unhelpful, which i find a shame as your previous posts on this subject have been most useful.

    You say research, but that is half my problem, if i don't ask questions then it is hard to find out. Your knowledge seems good and sound on Colour theory, but relativly low in terms of a Barco projector. I would guess that your more used to digital displays which seem to work slightly differently, or at least the terminology is different

    I have all the manuals for the BG808 and have been throughly through the install/user ones and they list little in terms of colour calibration. The Service manual is mainly circuit diagrams and rough workings, though there are some settings for pots and voltage. Part of the problem with these beasties is trying to undo someone elses incorrect tweaking as a lot of research out there is quite contradictory and what i've found six months ago on topics has change, sites died, gotten lost and hell i've probably forgoten more than my fair share too.

    I also don't neciseraily trust the set-up, there are lots of things in the loop and its using kit that isn't quite designed to do a job that we probably should not be doing anyway acording to the manufacturer that sold the business anyway....So sorry if i ask and check and maybe even double check some elimentary points.

    Cya,
    Lee
  16. Boris Blank

    Boris Blank Member

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    Hi Lee,

    This thread - http://www.avsforum.com/avs-vb/showthread.php?t=511455&highlight=spyder may be of use to you as well as the Display Calibration forum over at AVS. I'm sure Gary Lightfoot may also be able to help you out as he has recently started calibrating his crt(s) using a Spyder so he may very well offer some advice. The title of your post will be like a magnet to him!
    Paul
  17. Mr.D

    Mr.D Active Member

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    G2 is the pedestal black level , black point is your brightness settings. If these things mean nothing to you then go and do some research because I certainly don't advise you to be adjusting colour temperature without setting these first.

    Sorry if that offends you , try not to blow yourself up . That would be a real shame.
  18. Alaric

    Alaric Member

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    Hi There,

    Thanks Paul, that was one of the early ones that has set me off on this journey anyway. I saw long ago you mentioning that and another AVS thread when the SpyderTV was being released. I'd like to see that software but am a cheapskate as I had the Optical software that most of the AVS group use. I've now played with three sensors, most just looking and wondering. The Sequal Imaging Chroma is very old and while it works with Optical, i was never confident of the readings. I also have a Barco CAST which is technicaly designed for video walls for control rooms or something. I recently got the calibration data for it, but it was a couple or so years out and the software only gave me CIE U' V' +lux data and i knew the lux was out anyway...i managed to convert the data but that gave me really wierd stuff - Shame 'cos its an Ocean Optics USB2000 spectrometer - I may go back to that once i figure some more out !

    Mr D - G2 is master brightness from what i know. Technicaly on the BG808 set by going into the G2 Service menu and then twisting three indervidual pots until the green leds for each tube just turns off. However due to age etc and the fact that i know at least one of the RGB output amps have been replaced (i did it as i had really wierd red once) I'm not sure of the overall acuracy of it. Another method is in the same menu to tweak it until the raster is just glowing. One is subjective, the other maybe measured but could be inacurate. The way the LED is set requires an ocilloscope.

    Black point = brightness level. Now that makes sense, which i can understand and maybe figure out, however due to the nature of things i'd pref to check. Shame you didn't just say that, as the rest of your comments have been helpful and verbose. Don't worry i understand the level of black, contrast etc, it was just the terminology that threw me. Ta
  19. Gary Lightfoot

    Gary Lightfoot Active Member

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    Hi Al'

    I did see this post but MrD was helping out so I didn't offer anything - mostly because MrD knows this stuff better than me anyway. :)

    I still haven't gotten round to calibrating the CRTs as I've still got a few other projects on the go right now, but I was hoping to have had them set up by this time. :(

    I did have a try at Henry's Barco when I saw it some time ago, but we found that we could get 30IRE and 80IRE pretty much to D65, but we couldn't get the others close without throwing out the ones we'd already done. I think you need to tweak the gamma if possible to help bring the colours into line and a Lumagen with it's 11point greyscale adjustment might help if you can't do it with the HTPC, though there must be a way to do this on the 808 without external tweaking - I'm curious as to how it is done which is why I bought a CRT to play with.

    Have you taken a complete set of greyscale readings from black to white and have a graph we could look at? At least we could see what's going on and maybe if Gordon sees this thread he'll offer some pointers as well perhaps.

    IIRC, setting the white and black levels sets the green at those points, and is why you only need to adjust the blue and red after that; in theory your black and white levels should remain set in the most part.

    Gary
  20. Alaric

    Alaric Member

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    Hi There,

    Right, last night i did a re-check if the G2 settings, making sure the lights trimmed off, and checking visualy. The rasters seemed good and balenced.

    Tonight i've just installed the latest TheaterTek 2.3 and then went through Avia with ColourCop to check what the RGB values of each of the Black through to 100 IRE. Its using VMR9 not overlay so this works. TT is running RGB 18/15/18 to 235/233/236 as black and white levels. Having Colourcop open and checking the RGB value each time means that when i have trouble chaper changing etc i make sure i am on the right chapter...TT is a pain for this sort of calibration but if its the player i use then it has to be the one i calibrate for. I've found a semi-automated prog called S2xyY which i've altered the Ini file to 0 time so i have as long as it takes to change chapters and also renamed things so it tells me which chapter rather than just IRE70 etc. Its not automated, but it creates a nice cut&paste txt file of the numbers and doesn't write things down wrong in the dark:D

    Brightness/Contrast was checked prior and run at B42/C62. I also hit the calibrate button in Optical to do the screen synch setting on the white background

    I started off with my previous settings and did a run through which came out odd as i expected. I tweaked the Colour Balences for near 3.13,3.30 with +/- 0.02 and repeated until i got consistent reading within my tollerance.

    I ended up with Rg=52, Bg=49, Rc=36 Bc=23.

    The raw data B,10->100:

    0.326 0.329 0.243
    0.329 0.338 0.265
    0.326 0.348 0.721
    0.314 0.332 1.942
    0.315 0.330 4.092
    0.315 0.330 7.058
    0.316 0.332 11.090
    0.312 0.327 16.135
    0.313 0.329 22.418
    0.317 0.339 29.364
    0.320 0.348 37.810

    Gamma is high at 2.68

    Colour temp is a bit low, particularly at 10/20, but at 30 where i adjusted is at 6400 and is even to 80 where it drops to 6200

    Initial set was :

    0.297 0.26 0.399
    0.301 0.274 0.518
    0.297 0.292 1.488
    0.295 0.297 4.045
    0.297 0.303 8.049
    0.293 0.299 13.703
    0.298 0.31 21.166
    0.299 0.316 30.376
    0.298 0.322 40.444
    0.303 0.332 38.668
    0.302 0.333 42.291

    Whats the best way to export/import Excel images from this data ???

    Cya,
    Lee
  21. Mad Mr H

    Mad Mr H Member

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    Hi,

    Do you find TT 2.3 gives a bit of a "dark" picture ???

    I tried this a few weeks ago and I was not happy with the picture quality from TT 2.3.

    I also found the menu settings were very course for brightness, cont etc.

    I have gone back to power DVD6 for now......

    Might just be my settings but I thought from the start that TT 2.3 seemed to play too dark and loose detail.

    Only my opinion BUT I could net get a picture I was happy with........
  22. Gary Lightfoot

    Gary Lightfoot Active Member

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    The results look promising Al,

    Can you also give us the dE values for each IRE value? As MrD mentioned earlier, it tells you how far perceptually you are from D65, so at a glance we can see if you're in the ball park so to speak. How do the colours look now (especially skin tones)? More natural? Do you have a screen grab option in a paint program (like Paint Shop Pro)? That's one way to grab images for posting. Looking forward to seeing the results. If you can draw up a procedure for other CRT owners who like to tweak and can afford SpyderTV should be able to calibrate it to D65. :)

    MMH,

    Did you set TTs black level using a test disk? That would set the level so that you can see all detail above black. You should check the level with every different source if possible, even when you change DVD players, (software or set top box).

    Mind you, I bought an earlier version of TT and got a refund - I also stuck to PDVD6. :) 2.3 is meant to be much better though, especially with HD content.

    Gary
  23. Mad Mr H

    Mad Mr H Member

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    Hi,

    This is the really wierd thing......

    I was using HD content, and it was terrible!

    No black detail,

    ALSO things that should have been close to black were "BLACK" . Like creases in shirts etc. black jacket BUT should have been able to see the buttons, that kind of thing........

    Set up? Well actually no I did not bother, it was that far off and the adjustments were poor, VERY course and so nasty to work with.....

    I will give it another go but is was as if I had missed a "make things darker" tick box.......

    Like "black" was set above black if that makes sense?
  24. Gary Lightfoot

    Gary Lightfoot Active Member

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    Funny you should say that Andy, but I had exactly the same problem with HD stuff on my HTPC too at one stage (using PDVD or WDVD). I think I fixed it by either reinstalling either the players or upgrading the graphics card drivers) and making sure that it was in hardware assist mode. Now everything looks much better and the black level for both DVD and HD looks the same. Wierd but true...

    Gary
    • Thanks Thanks x 1
  25. Alaric

    Alaric Member

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    Hi Gary,

    Are you talking about the DeltaE versus D65 graph. A quick copy and paste into paint, i didn't know you could do that with Excel and vola all 4 images :

    Attached Files:

  26. Gary Lightfoot

    Gary Lightfoot Active Member

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    Excellent, thanks Al,

    That makes things easier to see. :)

    I've not seen dE as a graph, but it does the job well. It looks a bit lumpy top and bottom, but how does it compare to what it was like before calibration?

    Most sensors in our price range aren't that accurate below 30IRE anyway, and you'll often see graphs like yours (with all pjs, not just CRTs) where the lower IREs are all over the place. If the colours are genuinly off though (and you can see it), you may have to tweak by eye to try and get it looking right before using the sensor to calibrate the rest, and hope it doesn't throw the lower stuff out by too much. One way round it is to move the sensor closer to the pj, but with a CRT, does that mean you're more likely to put the sensor closer to one tube and not get an average RGB reading anyway? Can a diffuser in front of the pj be used to mix the colours for closer readings maybe?

    30 to 80IRE looks pretty good with a little teaking needed above. How does it look now compared to pre calibration?

    With fixed pixel projectors that use UHP lamps, we find that the red output from the lamp is less than the green and blue. So what we do is find where red maxes out and then reduce green and blue down to match.

    Does the Barco have less blue output compared to red and green? If that's the case you'll have to find where blue maxes out at 100IRE, then reduce red and green to match and calibrate from there to get a flatter graph. It may reduce your peak white level though. Another way round it may be to get some more colour acurate lenses which give a better colour balance but I don't know if that does balance the colours or not. What are 'C' elements?

    Gary
  27. Mad Mr H

    Mad Mr H Member

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    "C Element"

    Critical element

    These are used with Liquid Coupled Lens (LC)

    The housing on the front of the tube which contains the Glycol has a lens at the front called the "C Element" is it Part of the lens BUT attached to the tube housing.

    In 9" projectors you can get colour filtered C elements, there is currently some debate over the availablity of 8" units a group of us are trying to get some.....no details yet......

    The 808 series did have an LC option but it is very rare, again a small group are working on this BUT it is very involved and currently the gains are

    1. PJ closer to screen
    2. reduced Halo effect

    BUT this requires, LC housings, new lens, special mountings custom made,

    There is currently a down side that edge focus is then not so good, this is being worked on.......

    ANOTHER WAY is to use coloured glycol from other tubes, Seleco 400 and above I think, Barco 801 for sure and many others, buy dead tubes and use the coloured glycol.

    The use of prime filters has been mentioned by most as not a good option, optical quality filters are needed NOT the usual stage par can stuff.

    It is on my list to try all the above out, just gotta find the time......

    I find there is a lot of talk about all this from people who have never tried this out, in fact some of what I write above even.......

    This thread is great, thanks for sharing it with us all.......
  28. Mad Mr H

    Mad Mr H Member

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    Are you measuring at the screen?

    Center of screen?

    avoiding shaddow of unit?

    OR

    At the actual PJ guns ?

    In front of the lens or at the tube?

    Just curious.....
  29. Alaric

    Alaric Member

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    Hi There,

    Gary - The blue is almost always the weakest colour for a CRT projector to reproduce. There is talk about defocusing the electromagnetic part of the blue focus to increase light output, but i don't like that idea in principle. How quite you adjust to the blue when there are no direct options for green, i don't know.

    As for the picture, i watched King Kong last night and the colours were very vivid and bright, they seemed slightly sacharine sweet, but i don't know what it was suposed to look like....It really did bounce off the screen.

    Mad - Measuring the CRT not the screen. Reading bits on the spyder2 sensor its for measuring the light output not reflected output. I guess any bias the screen adds is not calibrated for though.

    On the BG808 there are two memories for each setting, i've calibrated no.3 and have copied the block to 93 which gave me an inbuilt 6500 colour setting when i watched things the other night. I will run through the measuring again on this as a uncalibrated start point, as i found after i had done it last night my uncalibrated setting was actualy my way off calibration i was talking about above (with the blue cut at 0) hence the uber wierd colour temp for 10% at 16333 !!!

    cya,
    Lee
  30. Alaric

    Alaric Member

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    Hi There,

    Just went back and at the same brightness/contrast settings using the Barcos inbuilt '6500' setting, colour temp is off the chart at 10,000-7,500. dE is off the graph too. Colour i've included below as well as gamma

    Raw data :

    0.281 0.266 0.366
    0.283 0.271 0.395
    0.287 0.290 0.879
    0.284 0.291 2.105
    0.286 0.294 4.215
    0.289 0.298 7.100
    0.285 0.294 11.144
    0.285 0.295 15.958
    0.292 0.306 21.918
    0.296 0.316 28.534
    0.298 0.323 36.520

    Cya,
    Lee

    Attached Files:

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