colorimeter for CRT's?

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deezdrama
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colorimeter for CRT's?

Post by deezdrama »

What colorimeter probes available these days work for calibrating CRT's and whats the process look like?
Dochartaigh
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Re: colorimeter for CRT's?

Post by Dochartaigh »

Not going to lie that I have a ton of experience doing this myself, but DO know what people tend to use from research since I'm in so many CRT groups and own so many PVM/BVM's.

I picked up an X-rite Colormunki Display off eBay for maybe $85. It uses the same exact sensor as the way pricier version (forget its name), but it's a little slower to do its thing (like seconds, nothing crazy).

Then the free software most use is HCFR, an open source display calibration software. Lots of videos on YouTube about how to calibrate CRT's (including PVM/BVM's) with this software.

Also be aware (and this is over my head for sure) that for a 'proper' calibration it's NOT just about the service menu settings while using a probe. It involves opening up the CRT and using an oscilloscope and such to tweak the hardware as well - this is talked about in most service manuals (well, I guess I should clarify in PVM/BVM manuals – I own way less consumer CRT's to know their intricacies as well). Sometimes replacement of parts like caps is needed if something won't get up to spec properly.
H6rdc0re
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Re: colorimeter for CRT's?

Post by H6rdc0re »

I fail to see why you would need to recap or even open a CRT display for color calibration.
nissling
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Re: colorimeter for CRT's?

Post by nissling »

deezdrama wrote:What colorimeter probes available these days work for calibrating CRT's and whats the process look like?
Basically all of them.

Or rather... Any colorimeter that you can profile with a spectrophotometer, or that has a color profile available for CRTs. The i1D3 (nowadays sold as the Calibrite ColorChecker Display) does and it's an excellent choice. I've seen some people suggest using RAW XYZ instead for a proper color profile but due to the peaks in IR at around 720nm that CRTs output you'll probably end up with some really weird readings. I strongly recommend using a generic CRT color profile for the meter or creating your own if you have the right tools.

As for software I prefer CalMAN tho I have looked into ColourSpace too lately. Never been a fan of HCFR but that's primarily a personal opinion; If you're new into calibration then it's probably a good place to start.
Dochartaigh
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Re: colorimeter for CRT's?

Post by Dochartaigh »

H6rdc0re wrote:I fail to see why you would need to recap or even open a CRT display for color calibration.
It's all outlined in detail in the service manuals - most of which is WAY beyond my comfort zone... I should also note that some of the below I mention isn't 100% color calibration, but in my eyes if your picture is blurry, blooming, has faint zig-zag stripes through it, or if your pure white screen shows up with streaks of red all through it because your red convergence is messed-up -- all of that in my book still falls under color calibration type stuff (as if that isn't right, you'll never, ever, get the picture looking proper and calibrated).

To give specific examples, just reading through the manual and listing some stuff I'm quasi-familiar with tweaking: you have to adjust focus via knobs inside the case (and can't have a nice color calibrated picture if everything is blurry), landing /convergence/ purity/ uniformity is adjusted via rings and dials/pots inside; G2 is via internal dial on most PVM's I believe - on a BVM the manual says it's in a menu but you need an oscilloscope (meaning, again, have to be inside the CRT's case) to set it properly.

Need a signal generator for most of this stuff too... digital multimeter is needed as well once you get more into things like checking if the high voltage regulator (integral to limiting bloom of the image, and having it look the best which is all part of 'calibration' in my eyes) is adjusted correctly.

If any of these adjustments can't be made within spec, that's when you would have to diagnose 'why', and where it's very likely a part or parts are worn/out-of-spec and need to be replaced. I'm most familiar with this on PVM's where if I just can't get the geometry right, no matter how much I turn pots or adjust the values, if new caps are installed in the deflection area for example -which I've only done meagerly– then it's back WAY, WAY better than before...

Probably lots of other stuff I skipped over I could have listed to, but I admittedly don't even know what some of this means TBH lol... just casually browsed through a random service manual for one of my BVM's in order to cite the above (hopefully I didn't screw up the verbiage too badly ;)
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elvis
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Re: colorimeter for CRT's?

Post by elvis »

nissling wrote:
deezdrama wrote:What colorimeter probes available these days work for calibrating CRT's and whats the process look like?
Basically all of them.
There appear to be a few budget models lately that are dropping support for refresh based displays. The Spyder X comes to mind. Any idea if that actually works on CRTs?

Yes, I know it's "cheap garbage". But not everyone can afford top of the line gear.

I'm still using an X-rite i1Display clone (older model, "Colourmonkey Display", OEMed from the X-rite) which I picked up for around $100 second hand at the time. The newer "Pro" version available today advertises a higher peak nit rating, which I don't need, but it's still nice to know that's available and CRT compatible.

The downside is the cost, clocking in at about $250 retail.
nissling
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Re: colorimeter for CRT's?

Post by nissling »

Haven't used the Spyder X so I wouldn't know.
elvis wrote:Yes, I know it's "cheap garbage". But not everyone can afford top of the line gear.
Depends on where you live. In Sweden the Spyder X is in a very comparable price range as the i1D3/Calibrite Colorchecker Display and thus there's no practical reason to go for the Spyder.

Considering how poor and unrealiable the meters from Datacolor have been historically, I honestly don't see why you would want to save $100 to get a Spyder when the Calibrite are both faster and more reliable. Considering how much time and effort you must spend into learning to calibrate monitors, going with the Spyder is a fairly weird choice to cut down costs considering that we are at most talking about price differences at $100-120. Especially considering that you cannot rely on the measurements you get from the Spyder.

EDIT: Comparing them on Amazon, the Spyder X Pro is priced at $129 while the Calibrite ColorChecker Display is $144. I have a really, really hard time seeing how spending $15 extra would break your bank.
Dochartaigh wrote:It's all outlined in detail in the service manuals - most of which is WAY beyond my comfort zone... I should also note that some of the below I mention isn't 100% color calibration, but in my eyes if your picture is blurry, blooming, has faint zig-zag stripes through it, or if your pure white screen shows up with streaks of red all through it because your red convergence is messed-up -- all of that in my book still falls under color calibration type stuff (as if that isn't right, you'll never, ever, get the picture looking proper and calibrated).
What you mention is mostly a question of servicing and installation. Calibrating a display is about comparing its image performance against a given reference, like BT.709, SMPTE-C or EBU, and correct inaccuracies without introducing new errors. In case your white balance is off, it needs to be calibrated. If the image is all fuzzy and blurry, it should be considered defective and needs to be fixed. It can be an easy fix or a very difficult fix.

I'd say your post makes perfect sense overall as there's no point in calibrating a display that has obvious color tints across the screen. However, there is a fundamental difference between servicing and calibration as they require vastly difference knowledge in technology as well as experience. Calibrating a display is about much more than just getting strraight RGB greyscale readings, much like servicing electronics requires more than just knowing how to replace caps. They are two very different rabbit holes and very few people have really gone through both, but I think it's good to have an understanding of each.
tongshadow
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Re: colorimeter for CRT's?

Post by tongshadow »

I bought an i1 Display Pro last month and it's a remarkable tool, very fast and precise readings and is capable of detecting very dark black levels, to the point I never managed to reach absolute 0 luminance without absolutely crushing black levels.
And according to other owners, it ages pretty well due to it using special filters that dont degrade, keeping the readings accurate even after longs periods of time.
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elvis
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Re: colorimeter for CRT's?

Post by elvis »

nissling wrote:Considering how poor and unrealiable the meters from Datacolor have been historically, I honestly don't see why you would want to save $100 to get a Spyder when the Calibrite are both faster and more reliable.
I certainly agree with you. I've always been disappointed by the rapid and substantial drift in Datacolor equipment in years gone by. And likewise I'd rather spend that extra on the Calibrite, given that I personally will be calibrating quite a number of displays.

Typically the issue is convincing others to bother buying the second cheapest rather than the cheapest, in the name of quality. That's a battle I just can't seem to win with others, especially when their argument is that they're only going to ever use it on a single display (which is never true, by the way, because as soon as they've calibrating their gaming displays, they realise the benefit ad want to calibrate other displays in their house).
pcb_revival
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Re: colorimeter for CRT's?

Post by pcb_revival »

I have a number of display types which could benefit from a calibration but have a nagging feeling that getting a professional product might be a waste of money after reading about quality control of said products and the apparent complexity of getting a calibration from my maybe miss-guided point of view.

Its one of those I coulda shouda done that.

Is there a product or opensource design that can be used with a raspberry pi or similar as a cheap entryway and is there good calibration knowledge primer - YouTube or a write up somewhere.
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Einzelherz
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Re: colorimeter for CRT's?

Post by Einzelherz »

Dochartaigh wrote:Not going to lie that I have a ton of experience doing this myself, but DO know what people tend to use from research since I'm in so many CRT groups and own so many PVM/BVM's.

I picked up an X-rite Colormunki Display off eBay for maybe $85. It uses the same exact sensor as the way pricier version (forget its name), but it's a little slower to do its thing (like seconds, nothing crazy).

Then the free software most use is HCFR, an open source display calibration software. Lots of videos on YouTube about how to calibrate CRT's (including PVM/BVM's) with this software.

Also be aware (and this is over my head for sure) that for a 'proper' calibration it's NOT just about the service menu settings while using a probe. It involves opening up the CRT and using an oscilloscope and such to tweak the hardware as well - this is talked about in most service manuals (well, I guess I should clarify in PVM/BVM manuals – I own way less consumer CRT's to know their intricacies as well). Sometimes replacement of parts like caps is needed if something won't get up to spec properly.
I woulda written all of this above here except that Dochartaigh already did. I, too, use a colormunki + HCFR. It works great, after a learning curve of getting used to.

http://www.curtpalme.com/forum/viewtopic.php?t=10457 Is the thread I used to help me get through the process the first few times. It has a good rundown.
deezdrama
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Re: colorimeter for CRT's?

Post by deezdrama »

Thanks for all the replies. I was looking at the colormunki and hcfr after watching a few videos on it.
I tried to do a little more research but read comments about certain probes not working with refreshing monitors so figured id ask.
How complicated are these to just get a decent simple color calibration?
I have a dozen or so pvms and consumer rgb sets id like to get calibrated but since they are just for gaming a "close enough" result is all I really need.

I havnt had a ton of time to research the topic with work and also trying to self teach crt troubleshooting.
Ive recapped almost a dozen crt's.... Some full recaps, most just power, neck board, and deflection circuits.
Its become a breeze for me to knock out a recap in an hour and have fixed alot of geometry issues and also just do it as general maintenance now on any crt I have open.
The problem is I have a couple sets with no power issues and beyond checking fuses and cold solder joints or throwing my esr meter on caps Im clueless how to troubleshoot a crt.
Ive ordered several books from the 90s but they all seem to be written for service techs who already know a great deal.

Anyway... I been reading Samuel M. Goldwassers faq on crt repair which is a little easier for the beginner to digest.
So ontop of wanting to learn crt troubleshooting and repair beyond just being a cap replacer Id like to learn to color calibrate crt's..... But again, I dont need to be super accurate, is hcfr and a probe the definite way to go or is there simpler approaches that get you close enough? Like using gels or something?
tongshadow
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Re: colorimeter for CRT's?

Post by tongshadow »

deezdrama wrote:Thanks for all the replies. I was looking at the colormunki and hcfr after watching a few videos on it.
I tried to do a little more research but read comments about certain probes not working with refreshing monitors so figured id ask.
How complicated are these to just get a decent simple color calibration?
It's essentially just displaying a color pattern (pure white, 30% white and 10% white are commonly used) and changing your monitor's color parameters (usually RGB Gain for white and RGB Bias/Cutoff for darker grey tones), through the service menu, to achieve the specified values your colorimeter is reading.

it's very simple when you actually do it, but it can be pretty involved if you're serious about getting the proper white balance point throughout the whole greyscale, and if you own a PVM you'll indeed see in practice they're all it's cracked up to be.
nissling
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Re: colorimeter for CRT's?

Post by nissling »

pcb_revival wrote:I have a number of display types which could benefit from a calibration but have a nagging feeling that getting a professional product might be a waste of money after reading about quality control of said products and the apparent complexity of getting a calibration from my maybe miss-guided point of view.
The Datacolor meters have historically speaking had poor quality control. The X-Rites/Calibrite ones however are more than good enough for consumer useage and are even used by many professionals.

Most people think that calibration is only about getting good looking graphs and readings. This is not true at all. Most of the procedure of a calibration is more about learning and understanding how a display works and functions. This is especially true among consumer grade TVs as they all function different and controls often don't work quite as you'd expect. Once you've understood the fundamentals and limitations of a display, you can more easily make adjustments that put the final image closer to target and make less compromises.

A graph over a greyscale with "perfect" readings don't say anything about the image in practise. Most often you measure 10 to 21 steps of the greyscale, making the readings only a small sample of all the shades. The ones you're not reading can be completely messed up. And the reading itself doesn't point out what compromises have been done to achieve the reading. Whatever values that are not mesaured may be completely off and will be very clear for just about anyone when looking at a greyscale ramp. Same thing with colors. You may manage to get secondaries and primaries at 100% saturation to read correctly but if any two opposite primaries and secondaries don't cross the read white point you've messed up the color matrix (basically there should be a straight line between red and cyan, magenta and green as well as blue and yellow that all go through the read white point).

Personally I think it's overall a great investment to start learn how to properly calibrate your displays. You'll get a much more consistent image and will be able to enjoy video game, movies, photos etc in a much more accurate way. However, getting good at calibration will take time and effort like anything else. As mentioned earlier, good readings don't always indicate that you've got a good image. Meters and signal generators should be seen as tools. You, the end user, is still the one performing the calibration.
tongshadow
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Re: colorimeter for CRT's?

Post by tongshadow »

This is why I like WinDAS/SONY DAS, basically foolproof if the tool is good enough for the job.
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NewSchoolBoxer
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Re: colorimeter for CRT's?

Post by NewSchoolBoxer »

H6rdc0re wrote:I fail to see why you would need to recap or even open a CRT display for color calibration.
I think most people have no need to do this and shouldn't be opening up a CRT to begin with. Spending over $100 for tools and equipment, can pass. My L2 PVM's whites have the vaguest tint of yellow that I never noticed until I placed a consumer CRT next to it. I'm okay with this.

That said, this is a hardcore place where people will spend hours to calibrate a CRT for perfection. I appreciate Dochartaigh's expert advice. If colors shift enough, maybe I will spend the time and money and calibrate. I'll never justify spending what PVMs cost today to replace the L2.

Other point is antique liquid/gel electrolytic capacitors will definitely fail at some point and are all probably out of spec now. Worst case, one leaks fluid over PCB traces that you could have avoided by replacing it earlier.

The internal AC to DC PSU is going to have to be maintained for similar reasoning. Lowered capacitance will send more ripple voltage/current into the circuity that will heat up television and age it faster.
Dochartaigh
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Re: colorimeter for CRT's?

Post by Dochartaigh »

NewSchoolBoxer wrote:
H6rdc0re wrote:I fail to see why you would need to recap or even open a CRT display for color calibration.
I think most people have no need to do this and shouldn't be opening up a CRT to begin with. Spending over $100 for tools and equipment, can pass. My L2 PVM's whites have the vaguest tint of yellow that I never noticed until I placed a consumer CRT next to it. I'm okay with this.

That said, this is a hardcore place where people will spend hours to calibrate a CRT for perfection. I appreciate Dochartaigh's expert advice. If colors shift enough, maybe I will spend the time and money and calibrate. I'll never justify spending what PVMs cost today to replace the L2.
I'm honestly no expert at the internal workings of a CRT, like at all (I mean, I technically own a multimeter but can do only like 3 simple things with it lol, with nearly no diagnostic ability on my end).

BUT, having 100+ PVM/BVM's pass through me in the last 4-5 years or so, I'll tell you right now the most common things I have to fix before I feel comfortable passing a monitor onto a fellow enthusiast, in descending order is: adjust the geometry, deal with a rotated image, adjust focus, fix convergence, and fix purity (or usually just reduce as much as I can).

EVERY SINGLE one of the above requires opening up the monitor on most models (ok, geometry only if it doesn't have a service menu; and some fancier models can rotate via the menu too – but what I said still holds true for most...).

Every single one of those, like I said before, kinda has to be done before you even start with color (and color TBH is the last thing I worry about, and only if it's noticeably off when next to one of my calibrated sets – the vast, vast majority have been pretty decent so I never touch it since we're playing video games and not color grading ancient videos in most cases).

Nearly every single one of those most-common type of issues I've experienced we of a degree where I really never needed any specialty tools for the most part, so no investment required either... It's just if you get deeper into it, or are into perfection, or have a really bad issue (like unfixable geometry without replacing caps), then of course it goes on from there in expertise and tools needed and such.
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