Correct gamma curve on 436SXE

[tig]

I wondered if anyone could help me with my attemps to calibrate my pioneer 436SXE using a spyder2 with HCFR software version 1.22 and the free patterns dvd?

After several attempts at measuring greyscale, making adjustments to RGB highs and lows and adjusting the secondary colours only I have managed to get almost exactly 6500k and 100% RGB saturation(delta-e 3 or less)from 10-90ire. However I cannot get anywhere near 2.2 along the whole gamma curve without adjusting the RGB highs and lows to such an extent that the picture becomes so dark that it's unwatchable.

Can I get close to the correct gamma across the range on this plasma or is it just not possible?

[D65]

Which gamma preset did you use?, 1, 2 or 3.

1 will give you the highest on a pio.

I ISF'd mine, and I get about 2.3.

Be very carefull trying to calibrate gamma issues using the grayscale, make sure brightness and contrast are what they should be first. When you trie to get a higher gamma count using the grayscale, it could very well be that your picture has degraded while your gamma is higher.

Dimitri

[Gordon @ Convergent AV]

Tig: Other thing to be aware of is that the power control will affect gamma curve

[D65]

Very true indeed.

When I put mine on powersave, It completely messes things up. In the form of an S-shaped gamma curve.

Dimitri

[tig]

Thanks Dimitri and Gordon for the quick replies.

I've currently got gamma set to 1 on the screen and get 2.2 gamma at about 10ire. The curve looks a lot like an "S". Power control is set to standard. I've set brightness and contrast using the spydertv software to 0 and 35.

I've included pics of the graphs for gamma, colour temp and rgb levels for 436SXE screen gamma settings of 1 and 2. I have also adjusted the secondary colours but not the primaries as you suggested in a previous thread Gordon.

Any ideas?

Thanks in advance,

Tig.

[D65]

Tig,

Your colortemp. looks pretty good. But your gamma is way off.

Are you sure the pio is not on powersave?, because that's exactly what it looks like. A pioneer usually has pretty good gamma when calibrated properly.

But I doubt this problem has been caused by a bad calibration.

What dvd player are you using, and what signal are you feeding the screen?.

Dimitri

[tig]

Hi Dimitri,

My screen has 4 settings in the power control section: standard, save1, save2 and picture off. I have it set to standard.

I'm using a PS3 as my source, via hdmi, set to upscale to 1080i with RGB range limited, super white off and the patterns disc is the one provided by hcfr.

Incidentally I have used the rgb highs and lows to get a higher gamma figure, but as I said in the previous post the picture is then so dark that it's unwatchable.

Thanks,

Tig

[tig]

Dimitri,

I see from one of your previous posts in a thread, you had the same problem as me in that when you got your gamma close to 2.2 your picture was also too dark to watch. I haven't adjusted the primary colours but I have with the secondaries, if this makes any difference.


" p.s. I get a very dark picture after calibration also, the wizard in datacolor takes me all the way in the - area of the pioneer, in between -30 and -10 for all rgb levels. "

How did you resolve the problem?

Thanks,
Tig

[Gordon @ Convergent AV]

If you have -30 to -10 for rgb drive and cut off in the ctemp menu then something is wrong. Forget wizards. Use your eyes and the tools. Stick everything back to midpoints in ctemp and aim for D65. After you've done that recheck brightness and contrast. Then adjust secondaries if you want, then go and check greycale is still D65.

[D65]

Tig,

Don't use the grayscale wizard.

Just use continuous readings and go back and forth between the cuts and gains. The wizard will take you back every time you use it, untill you end up somewhere in the -30's rgb's.

It's a very resctrictive(and silly) way to adjust the grayscale. And I don't understand what's the use of it. My colorfacts software has it, but I never use it anymore.

If your software has continuous readings, that's the way to go.

It coul very well be the problem relating to your gamma issue.

Dimitri

[tig]

Thanks Dimtri and Gordon,

I'll reset everything, use my original brightness and contrast figures and get as close to 6500k as I can.
Looks like I've either been trying to fix something that can't be fixed or my readings are wrong.

Thanks for the advice guys.

Tig

[D65]

Sure,

Post your findings when you're done.

Dimitri

P.s. leave green at 0 and adjust both red and blue to reach your target. favor blue errors(if nescessary)

[tig]

Dimitri,

Thanks for all the help. Here's my latest effort to improve the gamma curve.

It seems I won't be able to get perfect gamma(without the picture being too dark) by adjusting rgb high/lows, brightness or contrast, so looks like I'll have to compromise.

Thanks, Tig

[D65]

Tig,

This is not a calibration issue to my knowledge. I'm sure you set the grayscale and front panel controls correctly. Your color temp. looks very respectable with a delta 3 or less.

The graph looks like my gen. 6 on powersave(exactly).

What happens when you trie another powersave option?, either 1 or 2?.

Can you borrow another dvd player and run a grayscale for gamma comparison, this would rule the ps3 out...

Dimitri

[tig]

Dimitri,

I'll give it a try over the next couple of days on powersave 1 & 2 and run some more measurements with my Arcam dv27 for comparison. The dv27 will have to be connected via component so hopefully this wont affect results compared to connecting with hdmi on the PS3.

Thanks again,

Tig