CurtPalme.com Home Theater Forum

[Nashou66]

[AnalogRocks]

Color schmuller, blen in black and white.

Do it old school.

Congradulations on the fix.

[AnalogRocks]

Color schmuller, blen in black and white.

Do it old school.

Congradulations on the fix.

[Nashou66]

Still having a hard time getting this, Not sure what the problem is. I think it might be the EYE One probe but not sure. i changed out the Blu Ray Player also.
If i do the grey scale with out the Probe it looks good. However to do two PJ's by eye and have them match exactly is impossible.
Scott explained to me how to calibrate the Trim Pot capacitors on the peaking circuit , very cool and easy to do. got that set . But when I measure
the grey scale with the probe Blue is way to high for all readings according to the probe. But it looks fine on the Screen. So i follow the probe but
now all shades of grey become green, even the 90-100 IRE show the blue going over the 100% mark but looking at it you'd never know.
So I am going to try to set the grey scale with my Scope and or Multimeter.

The DVE disc tell you in the menu what the millivolts should be for each grey scale IRE. Where on the Vim or VNB would I measure?
Is it even possible to do it this way?

Athanasios

[1031]

Again i suggest that you trye with vim that has not those peaking caps in place..(older 2035-02p/03P) and see if you got better grayscale traking. When i testet that var.cap + resistors (like that new vim has) i foundet that it was near impossible to get good gray scale.

[Nashou66]

I did Jarmo, same thing, it must be the Probe.

Athanasios

[Nashou66]

Ok Im an Idiot!!!! I had Calman set for 0 voltage for the black level(PC value) Doh!!! Just did a quick set up and its all good now!! Well looks like i have some work next week!!.
it's my easter weekend now so family things come first.

Athanasios

[emdawgz1]

[Ridebreck]

Can you really set grayscale by measuring the voltage? Does this take into account differences in phosphors and the lack or presence of C-elements? I guess I was always under the assumption that you needed to measure the actual light coming out of the display. Interesting.

[Nashou66]

Its not so much measuring voltages only inthe PJ but also from the source to make sure you know what level of black its sending. I had the setting in Calman set to 0 volts for 0 IRE, this is a usual PC level or a PAL level for Black. So the source was sending 7.5 IRE as 0 IRE(most NTSC and HD sources) so the meter was set to read black levels starting from 0 but it was being pushed up because 7.5 is the sources black level. Is this is right all you experts out there?

What you can do at the PJ end is measure the patterns voltage for each color so they match, so you can use a scope to see it better, put up for example the
30 IRE window box and if you have two channel or three channel scope its easier as you can check all colors together. i have not done this yet but at least this is how i think its done. Ok, so you have the pattern up, On a marquee you connect the probe to one end of the large 400ohm resistor on the VNB and the ground end to the chassis or ground on the VNB. then you set the scope to show the pattern and adjust the values to the given value for each IRE, match the hight of the pattern for all colors the same and you should have the right amount for that color. I might be a little of in the technique and the actual logic behind it but its close. I idd it with the internal stair step pattern where you make each step the same distance from each other on the scope. each sep is one shade of grey in the pattern.

TSe could explain it better than I.

Athanasios

[Ridebreck]

This is probably a fairly elementary question, but I never did get too far in understanding the fundamentals of setting greyscale. So is true grey just equals parts of R, G, & B, and a certain IRE just a particular voltage level?

What still has me confused is that by my layman's understanding, an 8500 with 180dmb tubes and HD8 lenses would have different color output on the screen than the same 8500 with HD145s. Is this true? I guess my ultimate question is when DVE gives you the milivolt values, is the intention so that you can use it to set the greyscale for the display device, or to check the source device?

[garyfritz]

Yes, color-filtered HD145's will have very different color output. You have to re-calibrate your projector if you switch to color-filtered lenses.

[Nashou66]

It's to set the display device, not many source players have Color management.

The Purpose of the colored lenses for the AC machines and the colored C-elements is to help the phosphor achieve more closely the primary colors of red, and Green . This in turn helps get the secondary colors of Cyan,magenta,and yellow get closer. But now having said this the first attempt at doing the grey scale and measuring the primaries and secondaries on the long bow I was quite surprised to see how close they were. I am sure if i take the colored HD145's they have and put on the HD144 colored it be much better.

Athanasios

[garyfritz]

Oh, you can nail the grayscale exactly with the HD10's. Your grays will look perfect. BUT your fleshtones will look pasty, your greens will look muted, etc. The phosphor primaries aren't right so even if you jigger the balances to get the colors right for gray, the other colors aren't right. (I'm very surprised that your primaries & secondaries were anywhere near right.)

No wait, they already have colored HD145's? In that case you're already good. I don't think colored HD144's would be noticeably different, if at all. I suspect they use the same color filters as the HD145's. I think the only real differences between the HD144's and HD145's is a bit of aperture difference and focal length.

[Nashou66]

No gary these are clear HD145's . I was surprised as well, the green is the one that needs help though.

Athanasios

[stefuel]

[garyfritz]

Ah, OK. Then my original comments stand -- you can nail the grayscale but your other colors will be off. Yes the green is the biggest change, but the red helps a lot too...

[Nashou66]

[garyfritz]

FYI this old post shows comparisons with the HD8b's and color-filtered HD144's. As you said, the green gets the most benefit from the exchange -- the phosphor green is WAY off, and the HD144's move it to nearly dead-on correct SMTPE C green. I never tried swapping out just the green, or trying colored gels on just the green, so maybe the green is enough to get most of the color improvement. For sure the result with R & G color filtering is vastly superior to the unfiltered HD8b's (or your unfiltered HD145's). The native phosphor colors are just not right for proper color rendition.

[stefuel]

How do you find the focus from the 144's/145's vs the HD-8's and how much does it effect the throw distance? I was thinking about putting a set on that smokin 1080P 3600HD that I have.

[ecrabb]

Chip, I can't comment on the sharpness, throw distance or color-filtering of HD-144's, but I can tell you that HD-8's suck ass. Real, usable, resolvable resolution on every one of the half-dozen sets of HD-8's I've seen was down in the 960x540 ballpark. Maybe 600p, but that's really pushing it. I've mentioned several times how crappy I thought HD-8's (and their Sony variants) were, and how much they limited the performance of the lowly 12xx machines. Nobody every agreed with me, but then Perisoft was having trouble getting a sharp image on his 808. I suggest he compare the image on the tube face and on-screen, an sure enough - it was the sh*tty HD-8's that were the problem. They just suck. These are VGA/SVGA-era lenses, that's all they'll resolve.

Based on what I've read from people with XG's and people that have done Joust mods, I think the HD-144's should be a major upgrade.

SC