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Re: Monitor calibration question.

PostPosted: Mon Mar 09, 2015 6:30 am
by Mike Nagel
Christopher Cox wrote:Correct. My budget doesn't allow for an Eizo. I need to know how to make a comprise option work reliably.


just to clarify again: best case would be a US$9K (or higher) OLED, minimum entry level is Eizo CG...

if ur budget does not allow for that and u can't find a used one (somebody is selling 2 x Eizo CG on LGG), next step is finding a decent low-end screen (full Rec 709 coverage, least amount of uniformity issues [that will be hard], hopefully 10-bit in via HDMI) and use an external LUT box (eeColor) - this worked okay a while ago with the original HP Dreamcolor, but that screen also had wild uniformity issues...

if that does not fly, find again that (cheapo) screen, BMD Mini monitor, and use built-in Resolve 3D LUT...

I would look into lower end Eizo, NEC and maybe Benq... make sure the screen covers Rec 709/sRGB (same gamut).

get decent budget meters: colorimeter (i1D3) AND spectro (i1Pro Rev D) will be ur best choices.

You will have to use Argyll, as I doubt u'll have money left to spend for the premium cal apps.

Re: Monitor calibration question.

PostPosted: Mon Mar 09, 2015 6:38 am
by Paul Provost
If you have no budget, get a BMD mini monitor, send HDMI to the best tv you have at home, put it in cinema/movie mode, and it will be better than a cheap computer monitor and be vaguely close to rec 709. This will "loosely" resemble a real color pipeline.

Re: Monitor calibration question.

PostPosted: Mon Mar 09, 2015 6:47 pm
by Lee Gauthier
Paul Provost wrote:If you have no budget, get a BMD mini monitor, send HDMI to the best tv you have at home, put it in cinema/movie mode, and it will be better than a cheap computer monitor and be vaguely close to rec 709. This will "loosely" resemble a real color pipeline.


+1, folks get good results from Panasonic 10-bit plasmas (you can buy them used, no longer manufactured) and VIZIO 10-bit LCD TVs.

Best low-cost calibration is the x-rite i1 sensor ($150) plus dispCalGUI (free, open source) calibration software that works with Resolve.

Re: Monitor calibration question.

PostPosted: Mon Mar 09, 2015 7:41 pm
by Craig Marshall
Paul's suggestion above is a good one as modern consumer TVs seem to have developed faster than consumer monitors. However, I was disappointed with the HDMI output quality from the BMD mini-monitor as my initial tests with the BenQ PG2401PT reported severely crushed blacks and only an 8bit signal not 10bit like the included SDI output. It could be that the BenQ's HDMI input is only 8bit but I can certainly confirm both DVI and DP inputs are 10bit. From memory, the monitors specs indicate 100% sRGB coverage and 99% Adobe RGB.

FYI, I also use a modern TV as 'client monitor' - a 55" Sony X9000B 4K TV - and it is equipped with HDMI 2.0 inputs which report a 12bit resolution on some input signals. I feed the TV with a long SDI cable from Resolve out of a Decklink SDI 4K I/O card passed through a BMD SDI to HDMI 4K converter right at the set so as a test, I should plug the mini monitor's HDMI output into the X9000B and see what it reports compared with say, the HDMI 2.0 output from my GTX 970 GPU.

Re: Monitor calibration question.

PostPosted: Mon Mar 09, 2015 10:24 pm
by Mike Nagel
decklink mini is 10-bit 422 via hdmi

stating the obvious here:

do not use consumer tvs for grading, exception would be to use them as a client reference real world display... default presets on consumer tvs are severely messed up and DO NOT match default presets on other brands, e.g. Panny vs. Samsung...

Re: Monitor calibration question.

PostPosted: Mon Mar 09, 2015 11:39 pm
by Peter_r
I don't think anyone is going to use a TV with the default presets, more going to the preset that gives the most control and then using a probe to calibrate it as best one can.

Re: Monitor calibration question.

PostPosted: Tue Mar 10, 2015 12:05 am
by Lee Gauthier
Peter_r wrote:I don't think anyone is going to use a TV with the default presets, more going to the preset that gives the most control and then using a probe to calibrate it as best one can.


Agreed.

Most calibration processes for LCD or Plasma HDTVs start by having the user tune the TV to the most neutral setting, and then calibrate from there.

Re: Monitor calibration question.

PostPosted: Tue Mar 10, 2015 12:08 am
by Mike Nagel
u would naturally use ISF mode or Pro modes, but that was a statement in regard to another post in this thread... ;)

none of this is recommended.

Re: Monitor calibration question.

PostPosted: Tue Mar 10, 2015 5:27 am
by Christopher Cox
Lee Gauthier wrote:
Peter_r wrote:I don't think anyone is going to use a TV with the default presets, more going to the preset that gives the most control and then using a probe to calibrate it as best one can.


Agreed.

Most calibration processes for LCD or Plasma HDTVs start by having the user tune the TV to the most neutral setting, and then calibrate from there.


I have another very basic question--

When calibrating a screen which is fed by a PCIe card such as a BMD mini monitor, does the calibration software adjust only the settings in the BMD card to compensate for the screen?

I have to ask that just to make sure I understand the process.

Re: Monitor calibration question.

PostPosted: Tue Mar 10, 2015 7:13 am
by Lee Gauthier
When calibrating a screen which is fed by a PCIe card such as a BMD mini monitor, does the calibration software adjust only the settings in the BMD card to compensate for the screen?

I have to ask that just to make sure I understand the process.


No worries. Here's how it works:

The mini monitor gets the image signal from Resolve directly, without any color adjustment from the OS. The mini monitor converts the signal to HDMI and SDI without altering the color. This signal accurately represents the data coming out of Resolve. So the signal is good, but your monitor isn't neutral.

That means when the signal sends a pixel that is 100% pure white, your monitor shows a pixel that is not. It may be a little green, or a little magenta, or a mixture of several colors. We call this inaccuracy a "bias." Every monitor is biased uniquely, so each monitor must be corrected to neutral individually. Correcting the bias to neutral (so the color from the signal is displayed accurately on the monitor) is called "calibration."

To calibrate, you need an accurate signal going into the monitor (the mini monitor does this), a known color source to test the monitor, a sensor to read the known colors from the monitor, and calibration software to measure the bias based on the innaccuracy of each color sample.

An inexpensive solution is to buy an x-rite i1 sensor, and use dispCalGUI, a free open-source calibration app.

dispCalGUI works with Resolve to generate known color patterns, which the sensor reads and sends to the dispCalGUI software for analysis. When the sensing is done, the calibration software analyzes the samples and figures out the specific bias pattern of the monitor. The app then creates a color look-up table (LUT) that reverses the exact bias, rendering the monitor neutral.

You export the LUT after calibrating, and then load it for output from the mini monitor. So the pure signal from Resolve is being biased in exact reverse of the bias of your monitor. When your monitor shifts the color, it now displays the actual true signal colors, because the calibration LUT has offset the monitor's bias.

Since monitors shift color over time and due to environmental conditions, it's a good idea to recalibrate on a regular basis. Low-volume shops usually calibrate before each big show. High-volume shops calibrate on a regular interval, but not in the middle of a job.

Hope that clears it up a bit.

Re: Monitor calibration question.

PostPosted: Tue Mar 10, 2015 7:17 am
by Lee Gauthier
does the calibration software adjust only the settings in the BMD card to compensate for the screen?


If you find yourself working with an app isn't compatible with the mini monitor, you can use the computer's HDMI out to the HDTV in another input. This will probably be an 8-bit signal, but it's better than nothing.

To calibrate your computer's HDMI out, you'll have to use a color calibration system that works with the color profiling in your OS. Once you have the HDMI calibrated, you can switch inputs back and forth when you use different apps.

As I said, it's not ideal, but it can get you close enough to get work done.

Re: Monitor calibration question.

PostPosted: Wed Mar 11, 2015 9:43 am
by Ruben Carmona
I work with a HP ZR2740w. The 24" version of it is also very good for its price.

Calibrating with a Spyder4Elite. Very satisfied.

Re: Monitor calibration question.

PostPosted: Wed Feb 15, 2017 5:43 am
by Joel Goodman
Hi, thanks for this thread. I was wondering if you might help me take it one step further. I have Davinci, then a blackmagic Mini-monitor which splits off to a Sony Trimaster as the operator display (primary) via SDI and then the client display, an LG Oled via the mini-monitor HDMI. How do I go about calibrating the sony and the LG individually as both run through the mini-monitor?
Any help appreciated.

cheers

J

Re: Monitor calibration question.

PostPosted: Wed Feb 15, 2017 5:00 pm
by Paul Provost
you need to calibrate each display using each display's onboard menu controls along with calibration software/probe etc. Obviously you can't generate a calibration LUT to use inside resolve.