CurtPalme.com Home Theater Forum

jrodefeld · Joined: 19 Mar 2012 Posts: 16

Hello everyone,

I recently bought a used Pioneer KRP-500m plasma display. I want to perform a full calibration myself rather than spend the money for a "professional" calibration.

I want to have the best meters to use to get the greatest accuracy. I looked around and I found that I can buy an X-Rite EyeOne Pro spectrophotometer for remarkably low prices. Obviously a spectrophotometer will provide far greater accuracy than a colorimeter.

I already had an i1 Display 2 meter but I bought it used and I am sure that it is giving me inaccurate readings now. From what I understand, a spectrophotometer will not degrade over time and will give exceptionally accurate readings.

I want to know however, just HOW accurate a used EyeOne Pro spectrophotometer is. Do they degrade AT ALL? If I buy one used should I have ANY reservations about its accuracy?

Second, I read that a spectrophotometer is usually not sufficient by itself as it is unable to read accurately certain aspects of calibration (like contrast and gamma). Therefore most people also get a colorimeter to use on those aspects that the spectrophotometer can't accurately test for.

Now, my question is how much of a calibration can be done with only an EyeOne Pro and what needs to be done with a colorimeter?

I also read that while colorimeters are inaccurate (due to shift and degradation), if you reference them to a spectrophotometer they can become extremely accurate, even the inexpensive ones. As I already have an i1 Display 2 meter would there be any reason at all to buy a more expensive colorimeter if I can simply reference the Display 2 to the EyeOne Pro?

I think I understand the fundamentals of calibration pretty well. I am familiar with the software and I think I can perform the steps competently. The problem I have is worrying about the accuracy of my readings. That is why I want an Eye One Pro so I can be confident that the readings are precise.

Could you please advise me on when to use a spectrophotometer and when to use a colorimeter? I want to get "professional" like results on my KRP-500m and with the right meters and a bit of practice I think I could achieve that.

Any help or advice you could offer would be very appreciated.

Thanks.

Nashou66 · Posted: Tue Apr 02, 2013 3:10 pm Post subject:

I have an i1pro that i thought was maybe going bad. I sent it to Spectracal and they said it was dead on. ( it was my method that was wrong not the meter). They also told me they have had i1Pros over 7 years old that measured just as well. they said they never had a bad i1Pro come through their labs.

So what you do now is buy the i1 Pro and use it to profile the D2. The D2 will now have the same accuracy of the i1 pro and it will read much faster.

Later you can upgrade to a better Tri stimulus like the i one D3 or C6.

So every time you calibrate a display just do a quick Profiling of the D2 to the i1 Pro. I do the same.

Athanasios

**kal**

jrodefeld · Joined: 19 Mar 2012 Posts: 16

Thanks for the help.

I am still confused about one thing though. If a person already has a Spectrophotometer like the EyeOne Pro why would they ever want a more expensive colorimeter?

I mean, if an i1 Display 2 can be dead on accurate after being profiled to an EyeOne Pro what would be the advantages to a more expensive and "nicer" colorimeter?

**kal** · Posted: Tue Apr 02, 2013 6:25 pm Post subject:

Some reasons:

Something like the newer Display 3 reads incredibly fast - much faster than the Display 2. Very handy when doing auto-calibrate. You can be done in 30 mins instead of hours. For example, the Display 3 reads about 3 times after than the Chroma 5 which is already much faster than the Display 2.

The main advantages of the Display 3 is that it reads much more accurately, consistently, and lower (closer to black) than the lower end meters. It even reads better than some of the other higher end, more expensive meters. For example, the more expensive Chroma 5 is rated to read down to 0.01 cd/m2 light output while the Display 3 is able to read down to 0.003 cd/m2 (0.001 fL), or about one-third as bright. This is due to the Display 3 lens system which is able to capture and focus more light onto the filter diodes, providing much better low-light sensitivity and much faster readings (similar to the Hubble).

With the Display 2 you're not really going to be able to do any really low level work.

The Display 3 is also one of the easiest devices to use because, like the Chroma 5, it requires no dark reading calibration. Some meters require that they be covered up and a reading taken either when they're first connected or every 10-20 minutes as you calibrate. It only takes a second but it annoys a lot of people. For comparison sake, the Display 2/LT, EyeOne Pro / EyeOne Pro 2, and Hubble requires a dark reading when the meter is initially connected. The EyeOne Pro / EyeOne Pro 2 and the Hubble then also require periodic dark readings throughout the calibration session.

This is all from my FAQ here:

http://www.curtpalme.com/forum/viewtopic.php?t=11436

Kal

jrodefeld · Joined: 19 Mar 2012 Posts: 16

HogPilot · Posted: Thu Apr 04, 2013 11:38 am Post subject:

**kal** · Posted: Thu Apr 04, 2013 1:04 pm Post subject:

+1 to what what HogPilot wrote.

If doing 30/70 IRE points it's not much of a big deal. Low level gamma work however would be a nightmare. You'd be sitting there for hours. Most of the time waiting.

Kal

jrodefeld · Joined: 19 Mar 2012 Posts: 16

I bought an Eye One Pro on ebay the other day. It should arrive in a few days.

I have been plotting out how to do this calibration and I have a very simple question I can't seem to get a good answer to.

What should be my target gamma?

Now obviously the KRP-500m is a very high contrast display. I will be calibrating two modes, the ISF Day mode and the ISF Night mode. I was thinking for the night mode (where I watch in total darkness) I would shoot for a higher gamma, like 2.4 or 2.5. And for the day mode, I would stick with 2.2.

Does this make any sense? I really don't quite understand gamma that much. I have heard a lot of people recently claim that 2.5 is actually the target gamma. I somehow suspect that the KRP-500m with its massive contrast ratio will benefit from a higher gamma, at least at night.

Could anyone shed some light on this? Thanks.

**kal** · Posted: Sun Apr 07, 2013 3:09 pm Post subject:

There's lots of confusion on gamma, with no "one" answer. Somewhere between 2.2 and 2.5 is certainly where you should be aiming. You're in the right direction with the logic of day vs night.

See what looks good.

Kal

Nashou66 · Posted: Sun Apr 07, 2013 7:45 pm Post subject:

Gamma should consider the Viewing environment your planning on using and the Display technology.

If your main viewing is in a very dark environment then 2.3 to 2.4 would be ideal for most displays especially CRT

2.2 is the understood "standard" and does work well in room with some ambient light.

Also Just to make sure you did get an i1 PRO because the new i1 Display Pro is sometimes confused with the i1 Pro.

The i1 PRO

Nashou

Spanky Ham · Joined: 22 Mar 2006 Posts: 3967 Location: Comedy Central

I don't want to sound to much like a jerk, but you almost sound like you don't have a basic understanding of everything that you need to do for a calibration. Have you read Kal's primer? Actually you should read everything on the calibration forum. There is a big learning curve to this and you should ask yourself how much time you want to invest.

jrodefeld · Joined: 19 Mar 2012 Posts: 16

jrodefeld · Joined: 19 Mar 2012 Posts: 16

I have a few questions I would like to ask the members of this forum regarding my calibration effort.

First, a followup question regarding gamma. For my "ISF Night" mode, I will watch basically in complete darkness (or extremely low light). For this reason, I would like to try a higher gamma than 2.2. I was thinking of shooting for 2.4. From what I understand, a higher contrast ratio will yield an image that is more dynamic, with a higher appearing contrast that is more punchy. However there is a risk of black crush or low level detail being not revealed.

I have heard in several forum posts of calibrators who use a lower gamma at 0 to 30 IRE and then a higher gamma at 30 to 100 IRE.

Is this acceptable? Could you calibrate a gamma the gradually rises from 2.1 to 2.2 at 0 to a solid 2.4 or 2.5 at 30 to 100 IRE?

Would there be a tangible benefit to doing such a thing?

I don't know if any of you have any experience with calibrating the Pioneer Kuro plasma displays. But I really don't know how to calibrate the gamma. When I calibrate the grayscale using the RLow, RHigh, etc controls, I generally get a pretty flat gamma of 2.2. But how to I change that to, say, 2.4 across the board? There is something called "ISF Gamma" which supposedly controls the gamma in some way, but I don't really know how to use it.

I have heard that the Kuro Elites are able to achieve a pretty flat gamma response anywhere from 2.1 or so to 2.5.

Do any of you know how to calibrate gamma on these displays? Or, generally speaking, how to create a custom gamma like what I am describing above?

Second, I am using the Eye One Pro and I used it to calibrate the grayscale of my ISF Night mode. It seemed to work quite well without any major problems. I was able to get a pretty accurate grayscale without too much effort.

I used the actual Eye One Pro meter, rather than profiling it to the Display 2. I had heard that the Eye One Pro is significantly slower than a colorimeter like the Display 2. But that was not my experience. In general it seemed as quick as the Display 2, which makes me concerned that I am not using it right.

Also, it has been said that the Eye One Pro does NOT do well in low light conditions. So can I trust my grayscale readings at the low end? (0 to 30 IRE}. If the meter is inaccurate at those low light conditions, would that significantly affect my calibration results?

If I profile the Eye One Pro to the Display 2, would it not only be as accurate as the Eye One Pro in normal conditions but also be MORE accurate in its low light readings?

Is it a major impediment to an accurate calibration that the Eye One Pro can't do well in low light conditions?

Thanks for the help.

jrodefeld · Joined: 19 Mar 2012 Posts: 16

Does anyone have any response to the previous post? I would appreciate the help.

Nashou66 · Posted: Wed Apr 17, 2013 3:26 am Post subject:

You can do the Gamma method you mention. Just try it both ways and see which you like best. its trial and error.

Aslo I noticed with HCF program the i1 Pro is as fast as a Tri but with other Programs it is not.

I did not catch which program you are using.

But even had said that it read as fast I remember its repeatability at lower than 30 IRE was not consistent as with a tri stimulus unless i set the program to read more times or use a longer read time.

Athanasios

jrodefeld · Joined: 19 Mar 2012 Posts: 16

I tried a gamma of 2.35 to 2.4 and I didn't like the way it looked. Too dark. The best gamma seems to be somewhere between 2.2 and 2.3.

With that said, I have been improving and now I am able to get a perfect grayscale and a perfect gamma at around 2.25. But as far as the colors are concerned, I am a little confused, although they are better than they were before. I just don't know if the delta E errors for the primaries and secondaries are what would be considered "good" or if they could be improved upon.

Basically, I am getting Red with a delta E of 1.5 to 2. Green with a delta E of around 3. Blue with a delta E of around 6. For secondaries, I am getting Yellow with a delta E of 1 to 1.5. Cyan with a delta E of around 1.5 to 2. Magenta with a delta E of around 8 to 9.

Is this considered a "good" result for color? Obviously Magenta is the one that is off by the most, followed by Blue. The others look pretty good. Which ones are more important to get right?

How low a delta E would be considered imperceptible? Should I be shooting for delta E under 3? My understanding is that for primaries, it is more important that Red and Green be accurate than Blue. So Blue at 6 or 6.5 wouldn't be that noticeable?

As for secondaries, Yellow and Cyan have pretty low Delta E's but Magenta is way off. What does that affect? How perceptible is an inaccurate Magenta on picture quality?

Thanks for the help. I am still learning about calibration and I have been able to progressively get better results as I learn more.

How good are my primaries and secondaries?

Any feedback would be very much appreciated.

jrodefeld · Joined: 19 Mar 2012 Posts: 16

I have another question that I hadn't thought of until I read some other posts on calibration. I am using the AVS 709 disc to calibrate. Should I be using the 75% color windows or the 100% color windows to calibrate?

I have always been using the 100% windows, but I have read that some insist that you use the 75% windows to calibrate. Why is this? What should I do? I really don't understand this that well. What is the difference in the readings of the 100% windows vs the 75% windows?

Which one will give me the most accurate readings? Thanks.

HogPilot · Posted: Tue Apr 30, 2013 9:51 pm Post subject:

jrodefeld · Joined: 19 Mar 2012 Posts: 16

On a related note, as I am calibrating a plasma, I am curious which patterns I should be using to calibrate the grayscale. I was using the regular windows in the AVS 709 disc but then I heard some people claim that for plasmas, I should be using the APL patterns instead. I am a bit confused about the whole APL/ABL thing in relation to plasma tech and calibration. From my understanding, I am trying to get the gamma to be consistent when viewing normal content. And I believe the APL patterns simulate average content more than the windows, is that correct?

I actually went and checked the grayscale using the APL large patterns and it was significantly off compared to the windows. The gamma was not uniform at all and was far too high. It was not at all flat and measured like 2.37 on average when on the windows, it measured 2.5. I haven't checked the small APL patterns, but I suspect it will be significantly different again.

Which patterns should I use to measure the grayscale? Do I want the gamma readings to be (relatively) consistent between the windows and the apl patterns? Which will give me the best readings?