Basic Guide to Color Calibration using a CMS (updated and enhanced) - Page 52

So I wanted to confirm something from the Curt Palme site.

I am going to calibrate a Projector (RS2) and was going to buy the EyeOne Display 2/LT - well that was until I read the statement below. Does anyone use the EyeOne for projectors? What is your thought about this? The Spyder 3 is significantly more in their package but I obviously don't want to waste the money on a product that won't work very well for projectors. I don't care about the tripod part as I have one

The EyeOne Display 2/LT meter is the least expensive, reasonably accurate sensor recommended for home theater enthusiasts for direct view display calibration (not projector calibration - see the CalMAN Enhanced Spyder3 below). We do not recommend the Display 2/LT for front projector calibration as it does not include a tripod mount and the diffuser is not great for illuminant measurement (pointed directly at the lens on front projectors). The EyeOne Pro, the Chroma 5 and the CalMAN Enhanced Spyder 3 are better choices for front projector calibration (see below).

I use the LT from a tripod with no problems whatsoever. I originally just used masking tape to hold it in place and it worked fine, but my tripod was a little short, so I bought a $5 piece of aluminum and bent a right angle into it and drilled a hole it in, bolted it to the tripod removable bracket and now have about a 24 inch extension to the tripod. I just use 2" wide masking tape to hold it to the aluminum extension I made. Don't use the diffuser, just remove it and point the LT at the screen. I position mine so that one of the tripod legs is against the screen wall. That way, every calibration the meter is the same distance from the screen (about 20"). I then move the meter up and down, left and right and tilted forward, tilted back, until I get the highest Y reading (I use HCFR and set it to take continuous readings). I then lock everything down on the tripod and start calibrating.

I've never used a spyder probe, but am completely happy with the LT.

Thanks for the feedback. Yeah the diffuser comment was kind of confusing to me. First it said don't use the LT with projector due to bad diffuser. Then separately I saw over there - remove the diffuser.........

appreciate the feedback - anyone else feel free to chime in. Looks like the Eyeone is all I need and a lot "easier" to spend just over $150 vs $380.......

Tripod I have one that should do it fine and as you say attaching it shouldn't be a major issue

The Chroma 5 will be faster and I use multiple readings, usually 2, to smooth out the variations from one reading to the next. But be advised that HCFR does not support the C5. CalMan and ChromaPure do.
I use ChromaPure with the C5 and really like that program.

This post suggests the Colormunki:
http://www.avsforum.com/avs-vb/showp...postcount=1530
but that radiometer is only supported by CalMan at this time. AFAIK it is not NIST certified, the C5 is. Suggest you read the ColorMunki thread on the Cal forum before deciding.
http://www.avsforum.com/avs-vb/showthread.php?t=1215746

Thanks!

Received the ChromaPure/Chroma 5 today.

I had a request to show my homemade tripod mount, so attached are the photos (I couldn't see how to attach photos to the PM).

And 2 more.

I also own an i1Pro and this works fine with that, although I run the masking tape all the way around the body of the i1P.

Congratulations. Look forward to hearing hearing about your experience with the new toys.

knd - thanks a bunch

The link on the ChromaPure Site under the Lightness and Brightness article doesn't work.

http://www.chromapure.com/colorscience-lightness.asp

"What gamma value is closest to a perfect inverse of the lightness function? This source reports it as 2.32. Others claim that it is 2.35."

Works for me

Looks like a cut and paste error.

Or a CMS (content management system) [sorry couldn't resist] typo.

The link was in the sentence I quoted, not the article link I posted above.

(http://www.chromapure.com/http%7C//w...com/index.html)

By the way, doesn't that really mean the best gamma is at least two values?

Another possible reason for non-linear affects would be if your color balance is not linear when making changes to luminance. When altering the luminance at one of the control points, you'll be shifting the luminance response a bit thus shifting the color balance a bit as well. For example, if you have a spike of blue (e.g. 105%) at 65% stimulus and you lower the luminance around 70% using the ~70% 11pt control then it may be that you shift the blue spike closer to 70% stimulus thus it looks as though the color balance at 70% has changed. If the color balance across the entire stimulus range is linear then this effect wouldn't happen. On one of my Samsung displays, I have a distinct blue spike between 50%-60% but where I see it (50,55,60) depends on where I put the contrast control. So, I could see this as being one reason why one might see changes in the color balance as you alter the luminance at certain points even after initially optimizing the color balance.

cheers,


--tom

I have a question for those who have a lot more experience and technical knowledge at this than I do, although if I expend too more hours at this 'hobby', I should be able to qualify for a graduate degree pretty soon

My question is, which has more affect in reducing posterization/color banding, reducing saturation (all primaries are oversaturated) or the primary's brightness (all were too bright). After getting close on my grayscale (red is the problem child which the built-in defaults allow to run way low so I let it run a bit low but much better than the defaults), I started seeing skin tone highlights blow out on many HD TV stations (haven't seen it occur on BR disks).

So after giving up for a bit and reading more on the various approaches and compromises to balancing the color gamut, I focused on the saturations and primary's overall brightness. Basically, most colors were over-saturated at 25/50/75/100% but way under-saturated at 25/50/75 if I brought the 100% primaries in line (saturation wise). So I again compromised and decreased each primary's brightness using the color control and making a trade-off in saturation to get close in brightness (red is about 10% low, green/blue are 4-8% high) with most of the 25/50/75% saturations pretty close to target saturation leaving 100% somewhat over-saturated.

This seemed to eliminate (or make it almost undetectable) the skin tone posterization on those less-than-perfect TV stations. While I know grayscale can impact this area, since I reduced the red signal to avoid any blowout or clipping/tinting, that suggests this really is mostly a color gamut issue. I'm a type of person that just 'needs' to know what what fixed it (everything I've read suggests it's a 8 bit color conversation error for the larger gamut), but I would like to know, which of the two issues is the most important to target, primary too bright or primary too saturated (since I have to use both color controls to deal with the brightness issue).

Thanks in advance for any insight you can provide so I can sleep better at night :

P.S. My overall color reproduction is substantially better at this point.

[quote=Meret;18178100]I have a question for those who have a lot more experience and technical knowledge at this than I do, although if I expend too more hours at this 'hobby', I should be able to qualify for a graduate degree pretty soon
Snip....
IMHO the first task is to check for design deficiencies in the TV, using a benchmark like S&M:
http://www.avsforum.com/avs-vb/showt...ghlight=spears

The S&M showed among other things that the LG BD390 player was seriously clipping whites above 235 reference and that my LG 55LH90 had problems with cadence.
The white clipping would affect calibration so I now use the ChromaPure calibration disc in an old Panasonic S97 or AVSHD in a Panasonic BD60. The Getgray pattern disc is also very good.

The more one knows about the TV the better one is prepared to tackle calibration.

Here's one that is offered (I worked with another person on design).

It works well with the standard Chroma 5 / I1 Pro Mount and handle heavier meters like the K-10 and has vertical stability.. (adjustable horizontally - K-10 can go 20" from the center of the tripod head to the end of the boot.).

Just wanted to say that I am glad I ran into this Forum. I read all of the very first few pages and will continue to read them in order untill all have been read to better understand calibration. I am new to this and this is a great read for me. Special thanks to Tom for his write-up. It was very informative. I have bought some tools and software and am now venturing forward with my quest.
I will be calibrating my Sammy PN58B860 Plasma when I feel I am ready to tackel the job.

Thanks to all

Guys

I have a dpt-94 meter and HCFR. please look at my before and after CIE charts.

I know the Pio CMS sucks but I'm concerned that I had to move Green to -11 to get it to the after point.

Complete after settings: 0,-1,-11,-1,+2, -2

thx



bob

The dE is more important than the charts.

Do you mean from the gray scale run?

bob

Tom

How do you see de values on the CIE chart and how do you interpret them?

I understand how they work on the rgb scale.

thx

bob

Hi all, this is a great thread and the first post has helped me learn a great deal. I bought a Enhanced C5 a few weeks ago and have been going over the learning process. The FAQ for setting color and tint with a meter is priceless.

I love the control, to be able to experiment with your tv and find what works best over time. I have a Regza 55" 670U LED and would like some honest input.

*) I have tried both Gamma 2.25 and 2.33, using the Gamma slider on the tv, and feel 2.33 loses a little bit of detail (appears to crush a bit). It also is not close to the 2.2 gamma at 10% Tom recommends.

*) I've calibrated with both LD on and off (I use full field patterns on the AVS disc) because of a slight blooming issue in a dark room. When LD is on, and you watch a movie with dark scenes in a dark room (6500k backlight only), blooming can be very obvious and the you can see the zones turning on and off. With LD off, you do not see this, but you get the standard bright screen with no signal, which is quite annoying to me as an ex plasma owner.

Now, if I watch the movie in the early AM, with a small amount of ambient light coming in (no real reflections), I can no longer see blooming and have deep rich blacks. IMHO, these tv's, as well as other LCD's, are not made for the complete dark viewing like newer plasmas. I'm fine with this, because I have a 60w light off to the side that does not interfere with the tv, which is how I watch nightime tv.

*) I have a new DMP-BD85 coming, and will recalibrate when it gets here, to ensure there are no differences from the BDP-320. My question is, with an LCD like this with some ambient light, should I set the gamma slider where I get 2.2 at 10% and then deal with the result, or is say a 2.25 gamma, with a higher 2.28 (what I have now) at 10% low enough. That is with Gamma -2, so I can raise it to get the lower 10% close to 2.2, but the way this tv usually works, is that a 2.2 gamma at 10% will yield a lower total gamma than 2.2, so I will not be able to hit 2.2 at 10%, it'll be slightly higher.

If I am making any sense . I've set brightness with 3 diff discs (always 9-10), and it always takes major brightness adjustments from there to effect the 10% number towards 2.2, as in one of Tom's recommendations. So, it's my thinking that I have to set brightness right, then get my gamma where I want with the slider.

Long story short, it's my guestimation that I need to set brightness, shoot for an overall 2.2 gamma with the slider, which will prob yield 2.23 or 2.24 at 10%.

Thanks for any straightening of my confusion