[doodermonkey]

No matter what there is color in the grayscale pattern using the AVS disc even after calibration of my Panasonic plasma. The one where its a bunch bars in one screen with a top and bottom row.


I can calibrate and then go play with the settings back in the AVS grayscale and even visibly throw the whole grayscale off with a red or green tint for comparison. But when I set it back to what is supposed to be accurate there is still color in spots. The weird thing is it isn't necessarily a uniform tint. It's just color in random steps along the way. Not isolated to the low end or high end or in consistent clumps but like random bars in various spots. It could be red in a spot, green in another..


Also, if I mess with the contrast and turn it up and down the grayscale visibly shifts in color.


Is any of this normal? The picture actually looks pretty good outside of the grayscale when I put it back to what was calibrated, but its bugging me that I am not seeing shades of gray everywhere. I should be able to trust my eyes in this right?

 

[Michael TLV]

Greetings


May not be imagining it. Some sets have poor grayscale linearity and you will have a hard time fixing it. Dark gray to green to med gray to light gray to white. Or some other mix.


Turn the contrast control down by a whole lot and see if it goes away ... down to 60 ... 50 ... 40 ... see what happens.


regards

 

[monkies]

I had a similar post when i calibrated using my DVE disk (for my panasonic tc-p42g10). in the steps, i'll see a gray step, then 2 yellowish tinged ones, etc. all i know is that it's not uniform, and adjusting contrast doesn't affect it. the response i got was basically that some tvs just have this.


what tv do you have?

 

[doodermonkey]

Its a s1 model. Moving the contrast up and down seems to randomly shift which bars are innacurate looking but its not linear like if the white was getting overdriven. Ya guess its just the set and I should ignore it unless whole upper or lower end is tinted?

 

[monkies]

are you viewing in the THX mode? interesting how both of us have panasonics and have these non-uniform gray scale patterns easily noticable...is this something with some recent builds (just got mine in Jan 2010)?

 

[Michael TLV]

Greetings


S1 is not THX certified. Only the G and V and Z ones are.


regards

 

[thomasl]



Quote:
Originally Posted by doodermonkey /forum/post/18120750


The weird thing is it isn't necessarily a uniform tint. It's just color in random steps along the way. Not isolated to the low end or high end or in consistent clumps but like random bars in various spots. It could be red in a spot, green in another..

In addition to what Michael said, if you're looking at a grayscale ramp pattern where there are vertical bars representing 10%, 20%, 30% stimulus, etc. then often your eyes will see a tint to one of the bars not because that bar is tinted that color but because the bars around it are lacking a bit in that color thus your eyes are "drawing" out the color in the one bar that has it. For example, say 30% has a optimal RGB mix (D65) but 40% and 50% are somewhat tinted toward cyan (lacking a bit of red) but not overly so. In this case, your eyes may actually see the 30% bar as slightly red tinted. This is one of the reasons why it is very difficult to accurately calibrate grayscale using your eyes without some kind of visual reference.

Quote:
Also, if I mess with the contrast and turn it up and down the grayscale visibly shifts in color.

When you change contrast, you're changing the display's luminance response. Typically, depending on what the control actually does, you'll see the response shift to the left or right some as you move it down or up respectively.


hope this helps,



--tom

 

[mmoh00]

My 54s1 has the exact same issue. The ramp pattern had slightly different tint in each 5% bar that's not consistent with the grayscale meter reading (deltaEuv

I suspect the way Panny processes and drives the two images (IRE window vs ramp pattern) to the panel are different in some ways. Maybe some bug?


FWIW, I recently got a 65S1 and don't have the same coloring issue. Much better grays across the ramp pattern with similar deltaEuv's below 3.


BTW, I did not try lowering the constrast.

 

[doodermonkey]

Ya must be how panasonic does it. If I am going through the window patterns the grayscale looks great. Also, if I skip to the next pattern on the grayscale I was talking aboutwhere it just shows like 5 bars with the background shifting to variations of gray, the 5 bars will visibly shift color depending on which gray is being displayed on the background.


Weirdness...