Folks,

I have a G70 currently displaying a good picture (PAL 864p@75hz) but for one thing: A full white image is slightly pink on the right and slightly blue on the left. This is an even gradient across the raster. The tubes all look 100% with no sign or wear at all. There is no vertical variation in colour balance.
Do I have a fault or can this be adjusted out? :confused:

Thanks in advance.

Is it ceiling mounted or floor mounted? do you think you could post a pic?

Ceiling mounted. Connected via 5 x good quality BNC from a lumagen Pro - I’ll take a pic this evening and post tomorrow.

I was trying to rule out a tube toe-in issue. You might also need to make sure the active raster is central on the tube face.

What sort of screen do you have? if it is high gain or has glass beads or something similar you could be getting hot spotting or colour shift...so that the tube closest to either side of the screen is reflecting back at you manafesting itself in what you describe....

Will wait for the pics....

Folks,

I have a G70 currently displaying a good picture (PAL 864p@75hz) but for one thing: A full white image is slightly pink on the right and slightly blue on the left. This is an even gradient across the raster. The tubes all look 100% with no sign or wear at all. There is no vertical variation in colour balance.
Do I have a fault or can this be adjusted out? :confused:

Thanks in advance.

I'm assuming that if you are sitting in the center of the screen, the colors you see are on an all white screen just to the right and left of the center (not near the edges). If I am correct, you are seeing the infamous CRT color shift caused by the angles of the red and blue guns. It is more noticeable on PJs that have shorter throw lenses like your G70 or my Cine 8 Onyx. Not much you can do about it. It *may* be very slightly less noticeable on a lower gain screen, but you won't be able to make it go away. Also, contrast modulation (like my Barco has) can help decrease it a little, but it never completely goes away.

Do the colored areas move if you move your viewing position left & right? If so, it could be caused by color-shift from a high gain screen.

If not, it may be settings of the PJ itself. I haven't learned my way around my G70 yet but aren't there zone adjustments to let you balance the colors in different screen areas?

I’ve posted three pics but my ancient digi camera (handheld) doesn’t show the problem too well. It tends to hot spot the middle which is not there in person and it gets the colour balance completely wrong!

In taking these pictures, however, I noticed an interesting thing:
Looking at the internal white G70 generated white, in person, the white is good and even. Looking at a white generated by the Lumagen Vision Pro, produces the gradient.

I sit directly in front of the screen (1.25 matt) electric roller and the gradient doesn’t change if I move off axis, to either side.

Have a look at the G70 generated test (the one with “TEST MODE” displayed (ignore the “hot spot” in the middle – that’s just my ancient camera)). Look at the left and right – the colour is the same. In person this is a very even white all over. So no tube wear.

Now look at the (grainy – sorry, I’m apologising for my camera again) other “all white” image. I’ve played with the RGB on this one but can’t achieve proper white (must buy a new camera!), you’ll notice that the right side is pinker than the bluer left side. (Any splodges are camera artefacts).

Now look at the image from “Open Range” Again ignore the hotspot (camera) – the sky on the right is pinkish and the left bluish.

I have the Lumagen linked by 5 BNC to BNC 7m commercially made high quality leads.
What do you think?

Must be the source, the blue and red hotspotting would be apparent in the projectors all white start-up screen as well.

Can you go into serviceman mode, and whilst you have the lumagen feeding it a signal go in to one of the registration controls, mag focus, flip thru some of the internal test patterns to bring up the inverse ME pattern to see if this variable colour is source, frequency or projector related.....

Swap cables, bypass the Lumagen try a couple of options.....I don't think it's the projector (yet :rolleyes: )

Yes, if it doesn't show up in the internal all-white pattern, that tends to disqualify all the possibilities I was thinking of. I agree with newbieDAN -- try bypassing the Lumagen. Seems kinda hard to believe the Lumagen would do that, but...

Does the G70 have any colour modulation controls?

Does the G70 have any colour modulation controls?


I've no idea. I've not seen anything in the menus called that. Could it be called something else?

OK, I knew I'd seen something like this when I skimmed through the manual the first time, so I dug back through it and found it. Look on p. 57(EN) of the Installation Manual. In the service menu (ENTER ENTER UP DOWN ENTER) there is a "UNIFORMITY" option. It has a COLOR UNIFORMITY choice that can be off, set to the appropriate setting for the screen type (beaded or matte, as set in the SET SETTING menu), or manual. Manual lets you adjust blue and red in the horizontal direction, so I'm guessing it can resolve your blue/pink shift.

But since I haven't even set my new G70 up yet, I'm not expert, YMMV...

Yup, that'll be it.

Thanks for the suggestion.

Interesting…
From memory there are both brightness and colour uniformity settings: neither of them does anything. I’ve cranked them from one end of the adjustment to the other with no visible impact on the displayed pattern. :confused:

Huh. Then I'm stumped.

If you display ONLY red or ONLY blue, do you notice any brightness difference from left to right? This would be much harder to see than the slight color shifts, but it might be worth looking at.

Thanks for the suggestion.

Interesting…
From memory there are both brightness and colour uniformity settings: neither of them does anything. I’ve cranked them from one end of the adjustment to the other with no visible impact on the displayed pattern. :confused:

As I said way above, these controls won't fix the problem completely but only might make a slight difference.

I clicked on this topic for reasons completely unrelated to CRTs. I am disappointed.

I clicked on this topic for reasons completely unrelated to CRTs. I am disappointed.
:p :D