Large adjustments, should I be worried? Epson 8350 - AVS Forum
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post #1 of 29 Old 01-11-2012, 03:08 PM - Thread Starter
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Just did the first run of calibration of Epson TW-3200 (aka 8350 in the US) using latest AVSHD, PS3, SpyderII and ColorHCFR. After reading several reviews and people saying how well the projector is calibrated out of the box, I was surprised to end up with quite a few settings to get things right.

Here my settings - is there anything that jumps to you as odd?
Basic settings: Cinema, Iris hispeed, eco mode, skin tone 3 (default), NR off, super white off, HDMI range Expanded. I got BTB and WTW to show up, obliterated everything outside 16-235 with Brightness and Contrast.
Brightness -11
Contrast 11
Color Saturation -11
Tint -7
Color temp 7500k
Offset R -3
Offset B 1
Gain R 17
Gain B 3
Green offset/gain 0
Gamma 2.2 (default)

With this I got very good tracking of gray levels: deltaEs well below 4 from 30-100% greys, 20% was around 6. Grey was very close to 6500k, Cyan was quite close to reference, and red Y was ~21% of white Y. There are no clipped colors, and white and black points are good.

So although I had to make quite a few adjustments, they ended up really nicely. The main thing I'm concerned is whether there's something I should be concerned about with the large tweaks, or am I fretting about nothing?

I started with the color temp, perhaps I could get lower adjustments with calibrating with default 6500k - I might try that over the weekend.

edit: forgot advanced settings
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post #2 of 29 Old 01-11-2012, 03:58 PM
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Keep in mind that you are calibrating to the screen as well. It is not uncommon for screen materials to have large shifts due to manufacturing and the material itself. Hence, one of the reasons to use as neutral a screen as possible.

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post #3 of 29 Old 01-11-2012, 06:16 PM - Thread Starter
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Originally Posted by SierraMikeBravo View Post

Keep in mind that you are calibrating to the screen as well. It is not uncommon for screen materials to have large shifts due to manufacturing and the material itself. Hence, one of the reasons to use as neutral a screen as possible.

About that... My screen is actually a custom-made artists's canvas, so it was never even meant to meet any standard. It cost 105 EUR four years ago, a fraction of the cost of a proper screen, and works beautifully - but clearly is not optimal for accurate color reproduction.

For my second run, what's a good point to start? Should I reset color temp to default 6500k before setting Brightness/Contrast or grey levels. In other words, which of the basic settings is most likely to result in unwelcome color shifts, banding or clipping?
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post #4 of 29 Old 01-11-2012, 08:17 PM
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Quote:
Originally Posted by jouko342 View Post

Here my settings - is there anything that jumps to you as odd?
Basic settings: Cinema, Iris hispeed, eco mode, skin tone 3 (default), NR off, super white off, HDMI range Expanded. I got BTB and WTW to show up, obliterated everything outside 16-235 with Brightness and Contrast.
Brightness -11
Contrast 11
Color Saturation -11
Tint -7
Color temp 7500k
Offset R -3
Offset B 1
Gain R 17
Gain B 3
Green offset/gain 0
Gamma 2.2 (default)

With this I got very good tracking of gray levels: deltaEs well below 4 from 30-100% greys, 20% was around 6. Grey was very close to 6500k, Cyan was quite close to reference, and red Y was ~21% of white Y. There are no clipped colors, and white and black points are good.

So although I had to make quite a few adjustments, they ended up really nicely. The main thing I'm concerned is whether there's something I should be concerned about with the large tweaks, or am I fretting about nothing?

I started with the color temp, perhaps I could get lower adjustments with calibrating with default 6500k - I might try that over the weekend.

edit: forgot advanced settings

Couple things here. First you change skin tone to 0, all it does is shift the greyscale and then calibrate with your color temp at 6500k. If you're not going to do a custom gamma calibration set that to 2.4 because at 2.4 it actually is more like 2.2. While you do want to "obliterate" 0-16 with brightness, you want to set contrast just to the point where 255 is still showing. I have the exact same brightness setting as you but my contrast setting came out at +8. If you wan't you can use my cal as a reference.

http://www.avsforum.com/avs-vb/showp...postcount=6147

You're screen will probably net different greyscale settings for sure but everything else should be close.
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post #5 of 29 Old 01-12-2012, 03:19 AM - Thread Starter
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Originally Posted by Droid6 View Post

Couple things here. First you change skin tone to 0, all it does is shift the greyscale and then calibrate with your color temp at 6500k. If you're not going to do a custom gamma calibration set that to 2.4 because at 2.4 it actually is more like 2.2. While you do want to "obliterate" 0-16 with brightness, you want to set contrast just to the point where 255 is still showing. I have the exact same brightness setting as you but my contrast setting came out at +8. If you wan't you can use my cal as a reference.

http://www.avsforum.com/avs-vb/showp...postcount=6147

You're screen will probably net different greyscale settings for sure but everything else should be close.

Excellent tips on skin tone (wasn't sure what it does) and on gamma, thank you! I had an inkling there was something going on when I had to set temp to 7500k.

I'm not sure I agree on the 255. From what I've read there are practically no BDs which have any usable data above 235: BD spec is 16-235 after all. If I calibrate pure white to 255, actual whites from BD sources would be light gray, right?

I'll run a second calibration today or during the weekend.
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post #6 of 29 Old 01-12-2012, 06:09 AM
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Quote:
Originally Posted by jouko342 View Post

Excellent tips on skin tone (wasn't sure what it does) and on gamma, thank you! I had an inkling there was something going on when I had to set temp to 7500k.

I'm not sure I agree on the 255. From what I've read there are practically no BDs which have any usable data above 235: BD spec is 16-235 after all. If I calibrate pure white to 255, actual whites from BD sources would be light gray, right?

I'll run a second calibration today or during the weekend.

235 and 255 are not values of white, they are all white. They are different brightness of the same white. You set white with the gay scale setting, so if done correctly 0-255 will be D65 white just different brightness.. i.e. 10% bright 20% white up to 235 which is 100% white and 255 which is 109% white.
There are several threads out explaining it it comes down to this: if your display will show 255 then make sure when you are done, it still shows 255. All the caveats talked about in those threads aside, if you manually clip everything over 235 by cranking up the contrast you will most likely cause other issues..
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post #7 of 29 Old 01-12-2012, 06:19 AM - Thread Starter
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Originally Posted by airscapes View Post

There are several threads out explaining it it comes down to this: if your display will show 255 then make sure when you are done, it still shows 255. All the caveats talked about in those threads aside, if you manually clip everything over 235 by cranking up the contrast you will most likely cause other issues..

I've read numerous threads, and it boils down to BD content being encoded with only 16-235 of useful information, everything else is either noise or a very rare exception. Therefore I don't see what would be the point of calibrating a PJ to show anything above 235 for BDs.

There might be a point if one uses a PC as main source, and the entire I/O chain supported 0-255.
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post #8 of 29 Old 01-12-2012, 06:40 AM
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Quote:
Originally Posted by jouko342 View Post

I've read numerous threads, and it boils down to BD content being encoded with only 16-235 of useful information, everything else is either noise or a very rare exception. Therefore I don't see what would be the point of calibrating a PJ to show anything above 235 for BDs.

There might be a point if one uses a PC as main source, and the entire I/O chain supported 0-255.

Do what you want.. but when some of that content is displayed, cause it is out there your display may end up showing you some real funky colors.. it is your display, do what you think is best.

Think this was the same question... http://www.avsforum.com/avs-vb/showthread.php?t=1385918
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post #9 of 29 Old 01-12-2012, 07:12 AM
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Quote:
Originally Posted by airscapes View Post

it comes down to this: if your display will show 255 then make sure when you are done, it still shows 255.

The ideal situation is to calibrate gamma and grayscale all the way to maximum white (254). From a practical perspective, one issue with trying to calibrate to the ideal is that displays are limited in the amount of available contrast for gray calibrated to D65. By calibrating gamma and grayscale only to reference white (235), instead of maximum white (254), it's generally possible to make typical whites brighter. A few years ago I believe consumer calibration software such as Sencore and CalMAN focused on the 16-235 range, so typically if you hired someone to do the job that's what you were going to get, gray calibrated to reference white (235). I'm well aware of people claiming "specular highlights" appear in DVD and Blu-ray material and exceed reference white. Since I was unable to verify such claims, I personally question if there's much practical reason to calibrate to the ideal, since primarily what you're doing is dimming typical whites.
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post #10 of 29 Old 01-12-2012, 07:39 AM
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Quote:
Originally Posted by jouko342 View Post

I've read numerous threads, and it boils down to BD content being encoded with only 16-235 of useful information, everything else is either noise or a very rare exception. Therefore I don't see what would be the point of calibrating a PJ to show anything above 235 for BDs.

There might be a point if one uses a PC as main source, and the entire I/O chain supported 0-255.

The 255 number you see on the cal disc represents 235 or the upper limit of your source material. I know that doesn't make sense but trust me that's what it is. Here's a video from Spectracal, notice all boxes are visible up to 255.

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Originally Posted by Droid6 View Post

The 255 number you see on the cal disc represents 235 or the upper limit of your source material. I know that doesn't make sense but trust me

I'll take it that you're talking about computer playback. Typically computers expand video to the computer range, so that 235 from the source ends up output as 255 in the computer range. The more general expectation, for example when using a Blu-ray player, is for 235 from the source to also output as 235. Between the two scenarios, the latter is generally considered the more ideal option.

Note: 255 is not a valid gray luma for typical video found on commercial Blu-rays and DVDs
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post #12 of 29 Old 01-12-2012, 10:34 AM
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Originally Posted by alluringreality View Post

I'll take it that you're talking about computer playback. Typically computers expand video to the computer range, so that 235 from the source ends up output as 255 in the computer range. The more general expectation, for example when using a Blu-ray player, is for 235 from the source to also output as 235. Between the two scenarios, the latter is generally considered the more ideal option.

Note: 255 is not a valid gray luma for typical video found on commercial Blu-rays and DVDs

i may have worded that entirely wrong, haha. This is a difficult thing to explain. If 235 was the highest output of a video signal and you see bars up to 255 on a cal disc then the two aren't directly aligned the numbers on the pattern are just a reference point for clipping.
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post #13 of 29 Old 01-12-2012, 02:46 PM - Thread Starter
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Echoing alluringreality, I'm not talking about computer playback, but BD from a PS3. I merely mentioned PCs as a potential reason to calibrate for 0-255 for those who use it as their main source and whose entire I/O chain supports it.

Since anything outside of 16-235 is out-of-spec for BDs, I still don't see the point of calibrating to 255, as that would leave "BD white" ever so slightly grey. This is assuming something in the chain doesn't expand it to 0-255, which I assume some GPUs would do - in this case whites and blacks could be clipped if the PJ expects a 16-235 signal.

While my current calibration (done to 235) looks good, I haven't scrutinized the whites thoroughly. I'll try to find some movie scenes from my BDs with plenty of whites during the weekend to see if there is any benefit from calibrating to 255.
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Originally Posted by jouko342 View Post

Echoing alluringreality, I'm not talking about computer playback, but BD from a PS3.

That's what I'm talking about too. You should set your projector so you can see the contrast pattern all the way to 254 with your PS3 set to limited.
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post #15 of 29 Old 01-12-2012, 03:36 PM
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So what is a legal value for video?

Y: 177, Cr 173, Cb 162?
legal value for Y are 16-235, for Cr and Cb 16-240.

Surely that's a legal value, but what is it in RGB?
R 248, G 150, B 240

Red and Blue both well above 235.

Assuming rec.709 and a reference white of 83 cd/m (peak white of 100cd/m), that triplet should yeild a color of xyY 0.3240, 0.2383 with a Y of 48.06. If you clip the R and B values to 235, you get xyY of 0.3169 0.2396 and Y of 45.47

This is a dE76 difference of about 5!

If you don't want to take my word for it then perhaps this quote might:
"Consumers tend to think bigger numbers are better - but the clipped
picture will suffer. A home theatre calibrator, on assessing the greyscale response, will be savvy to this trick, and will adjust the display to
follow the gamma curve all the way up to peak." -- Charles Poynton
http://www.spectracal.com/downloads/...e%20colors.pdf

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post #16 of 29 Old 01-12-2012, 03:38 PM
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I think it's most important to make sure that 100% White is as close to 100%R 100%G 100%B as possible. If any of the colors start clipping, then contrast is too high.

When I do this, my contrast usually ends up showing up to 244 flashing on the AVSHD contrast pattern.
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post #17 of 29 Old 01-12-2012, 03:39 PM - Thread Starter
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Originally Posted by Droid6 View Post

That's what I'm talking about too. You should set your projector so you can see the contrast pattern all the way to 254 with your PS3 set to limited.

My understanding is that PS3 outputs all BD/DVD content with YCbCr, and that Limited/Full setting doesn't impact BD/DVD output. I just did a quick test with the AVSHD calibration disk, and didn't see any difference on black or light levels between Limited and Full.
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You should setup a PS3 to use Y,CbCr w/ super white on to the full range for BD playback.

I would use YCbCr for gaming on a PS3 as well since TV's frequently treat RGB differently than YCbCr.

If I did switch to RGB, I would use RGB limited as mixing and matching full range sources with other sources (your wii, your cable or satellite box or any other standard consumer electronics devices) can wreak havoc on the simplicity of your setup, especially if you have it all routed through a receiver.

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post #19 of 29 Old 01-12-2012, 04:27 PM
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Quote:
Originally Posted by sotti View Post

So what is a legal value for video?

Y: 177, Cr 173, Cb 162?
legal value for Y are 16-235, for Cr and Cb 16-240.

Surely that's a legal value, but what is it in RGB?
R 248, G 150, B 240

Red and Blue both well above 235.

Assuming rec.709 and a reference white of 83 cd/m (peak white of 100cd/m), that triplet should yeild a color of xyY 0.3240, 0.2383 with a Y of 48.06. If you clip the R and B values to 235, you get xyY of 0.3169 0.2396 and Y of 45.47

This is a dE76 difference of about 5!

If you don't want to take my word for it then perhaps this quote might:
"Consumers tend to think bigger numbers are better - but the clipped
picture will suffer. A home theatre calibrator, on assessing the greyscale response, will be savvy to this trick, and will adjust the display to
follow the gamma curve all the way up to peak." -- Charles Poynton
http://www.spectracal.com/downloads/...e%20colors.pdf

OK... haha, that being said what is your opinion on how high or low you should set contrast?
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post #20 of 29 Old 01-12-2012, 04:57 PM - Thread Starter
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I just tested white levels with BBC's Planet Earth - Ice Worlds BD, which has plenty of whites all the way to specular. The 235 calibration looked good, but the one I calibrated to 252 had slightly grey whites with no additional detail. This in my view confirms that 235 is the correct calibration - or is there another explanation?

Quote:
Originally Posted by sotti View Post

You should setup a PS3 to use Y,CbCr w/ super white on to the full range for BD playback.

That's my understanding as well, and that's what I've had it set up for years.

Quote:


I would use YCbCr for gaming on a PS3 as well since TV's frequently treat RGB differently than YCbCr.

How can you force games to YCbCr? Is that Deep Color output off in Display Settings?
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post #21 of 29 Old 01-12-2012, 06:30 PM
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Quote:
Originally Posted by jouko342 View Post

I just tested white levels with BBC's Planet Earth - Ice Worlds BD, which has plenty of whites all the way to specular. The 235 calibration looked good, but the one I calibrated to 252 had slightly grey whites with no additional detail. This in my view confirms that 235 is the correct calibration - or is there another explanation?



That's my understanding as well, and that's what I've had it set up for years.



How can you force games to YCbCr? Is that Deep Color output off in Display Settings?

White might not go above 235, because they may have clipped Y at 235 in the mastering processes. That does not mean individual channels can't have excursions into the 235+ range. Plenty of YCbCr values work that way.

I always, always allow as much range to peak white (109%) as possible, which usually means at least 253 visible.

Also how can whites be grey? Whatever is the brightest thing in your field of view is white. My monitor is set to 120cd/m but it can go to 350cdm. If I had two, one at 120 and one at 350, the one at 120 would look grey, but without a brighter reference 120 looks plenty white.

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post #22 of 29 Old 01-12-2012, 06:44 PM
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Quote:
Originally Posted by sotti View Post

I always, always allow as much range to peak white (109%) as possible, which usually means at least 253 visible.

That's always what I've read/done and this thread is the first time I've ever heard of anyone otherwise but it seams like every time I think I know something somebody pops up and says it's wrong. Thanks for clearing that up. Maybe you can clear something else up for me. If video levels are limited to 16-235 why do the patterns always run up to/or near 255? Is it a conversion thing (16-235 to 0-255), do video levels still allow for 236-255 it's just not commonplace or something totally different?
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post #23 of 29 Old 01-12-2012, 07:06 PM
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Quote:
Originally Posted by Droid6 View Post

That's always what I've read/done and this thread is the first time I've ever heard of anyone otherwise but it seams like every time I think I know something somebody pops up and says it's wrong. Thanks for clearing that up. Maybe you can clear something else up for me. If video levels are limited to 16-235 why do the patterns always run up to/or near 255? Is it a conversion thing (16-235 to 0-255), do video levels still allow for 236-255 it's just not commonplace or something totally different?

For the history on it I suggest reading this article.
http://www.spectracal.com/downloads/...e%20colors.pdf

Most of it goes back to the days of analog, when this stuff was being broadcast over the air.

Obviously as pattern discs store pluge (below black) and peak white data, the mpeg encoding scheme allows you to use the full range of Y. The article goes into some detail about why those range stops were set.

As I pointed out several post up, values that are completely with the standard range, when decoded to RGB create values that are much greater than 235.

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post #24 of 29 Old 01-12-2012, 07:17 PM - Thread Starter
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Quote:
Originally Posted by sotti View Post

White might not go above 235, because they may have clipped Y at 235 in the mastering processes. That does not mean individual channels can't have excursions into the 235+ range. Plenty of YCbCr values work that way.

Ok, that's starting to make sense I'm more familiar with (still) photographic color spaces, but I don't know YCbCr.

When I calibrate to 235 I don't get any clipping according to the color bars showing clipping on the AVS HD disc (third pattern on Misc. Patterns IIRC). This would imply they don't "have excursions" beyond 235, and as such are of limited value.

Quote:


Also how can whites be grey? Whatever is the brightest thing in your field of view is white. My monitor is set to 120cd/m but it can go to 350cdm. If I had two, one at 120 and one at 350, the one at 120 would look grey, but without a brighter reference 120 looks plenty white.

My bad, I used inaccurate language. What I meant by "grey" is that the whites have less luminosity when calibrated to 252, than the same setting calibrated to 235. The only difference between the two is contrast setting. The 252 is based on my 235 calibration; I didn't bother to recalibrate the 252 from the ground up. But based on what you said above, I will do that tomorrow - I might be able to get higher than 252.
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post #25 of 29 Old 01-12-2012, 07:32 PM
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Quote:
Originally Posted by sotti View Post

For the history on it I suggest reading this article.
http://www.spectracal.com/downloads/...e%20colors.pdf

Most of it goes back to the days of analog, when this stuff was being broadcast over the air.

Obviously as pattern discs store pluge (below black) and peak white data, the mpeg encoding scheme allows you to use the full range of Y. The article goes into some detail about why those range stops were set.

As I pointed out several post up, values that are completely with the standard range, when decoded to RGB create values that are much greater than 235.

I'm pretty sure I got it now (probably not but I'm going to pretend I do because every explanation makes my brain hurt more).
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post #26 of 29 Old 01-12-2012, 09:23 PM
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jouko342 if you get into a CMS cal make sure you read this guide as it applies to our Epson as well.

http://www.avsforum.com/avs-vb/showthread.php?t=1134710
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post #27 of 29 Old 01-13-2012, 02:18 AM - Thread Starter
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Originally Posted by Droid6 View Post

jouko342 if you get into a CMS cal make sure you read this guide as it applies to our Epson as well.

http://www.avsforum.com/avs-vb/showthread.php?t=1134710

Thank you, excellent post I haven't seen before. Pretty surprising results shown there. How accurately were you able to get the primaries and secondaries to track with the CIE targets with your 8350? Did you use the guide you linked to to get there?

I haven't worked much on getting primaries dead on, yet. I did check them early on, and all of them were oversaturated at 100 IRE (or was it 75) - haven't checked calibrated results.

I used the method described by Curt Palme (and others), where you set Red channel Y to 21% of pure white Y at 75 IRE (had to drop saturation quite a bit), and Cyan to REC 709 reference values of x=0.225 / y=0.329 (I only minimized the sum of deltas as I wasn't able to get to reference with Tint control alone). I did some quick checking with The Tourist and it looked good - but it could be just because the movie is useless as a reference disk since all you do is stare at Angelina Jolie :P

BTW, I re-calibrated with 6500k, skin tone 0 and gamma set to 2.4 as you suggested earlier - you were correct, it resulted in gamma of 2.2 and good calibration. So thank you! Next steps are to re-calibrate with 16-25x (as high as it goes), and go deeper into the CMS to see if I can get the primaries to line up along the CIE chart as per your link.
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post #28 of 29 Old 01-13-2012, 05:26 AM
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I did calibrate my CMS with the guide and at 75% saturation I was able to get all my primaries and secondaries dead on.
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post #29 of 29 Old 01-13-2012, 02:25 PM - Thread Starter
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Originally Posted by Droid6 View Post

I did calibrate my CMS with the guide and at 75% saturation I was able to get all my primaries and secondaries dead on.

I just finished the first full calibration which took around 2 hours, and am very happy with the results DeltaEs around 1 on grayscale, tracking very nicely with 2.2 gamma, 6500k temp, colors and even saturation. I was surprised how well-behaved the CMS was: I set all the saturations at 75% saturation, went back to grayscale and gamma to tweak it back to reference. After returning back to 75% saturation targets I had to make only very little adjustments.

The only issue I have is with green saturation (post here), but I think I can live with that.

Thanks again for all the help, especially Droid6!

Now it's Blade Runner time

edit: BR looked gorgeous, deep blacks, faithful skin tones, and bright whites. That movie never gets old.

edit2: I ended up with going back to 16-235 despite recommendations above. I re-calibrated with 16-235, and as expected whites are now brighter than 16-252, there's no clipping of colors according to the color gradients, and the calibration required less tweaking. Calibrating to 16-235 instead of 16-25x should also improve contrast.
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