basics of color correction (tv part)

[rodneyb56060189]

I found this really good and concise explanation of color basics re: basics.  It was some guy in Los Angeles, who won't mind me sharing this.

I just copied pasted stuff to notepad and won't edit the thing ...you'll get the idea the way it is...It's pretty cool way of just explaining and might help eliminate some confusion, like my own, for example.

=========begin paste=====

The Mini Monitor isn't just a TB to HDMI adapter, like the adapters your can buy for $7 off Amazon.

It converts a computer data signal to a TV signal. Fundamentally different types of signals. This is why you can't just plug a TV directly into your HDMI port in your computer. It would show up as second computer monitor, extending your desktop, displaying a computer signal.

TV video signals can be progressive, interlaced, different frame rates, and adhere to standard formats like ATSC, PAL, etc., encoded in Y'CbCr. Computer video signals are different beasts entirely, and computer monitors that are color-accurate and 10-bit for graphics work still are not equipped to handle interlaced signals or the various frame rates you find in TV signals.

The Mini Monitor's purpose is to allow you to view a true TV signal.

Thus BMD would never need to build in a second-screen full screen video playback like Premiere or FCP into Resolve, at least for color correction, because that could never be a true TV signal. It might, however, be useful in Resolve's growing capacity as an NLE apart from color correction, to be used purely as a non-accurate preview for editorial purposes (which is what Premiere and FCP and other NLEs are doing).

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The issue here is the type of signal. As the broadcast online editor and/or colorist, you are responsible for shaping and delivering the actual deliverable end product: an electrical signal. Not a picture, not an image, not a video. These are higher-order constructs that exist in our minds. The actual thing that we are delivering, wether by file or by tape, is a representation of an electrical signal. A very particular type of signal. You need to monitor the kind of signal you are going to deliver. So you have to monitor your images as a TV signal.

A computer display with an application window full-screened is a computer signal with information about all sorts of stuff. It is not a TV signal.

You need to be able to "see" your signal. This means to view the pictures encoded by that signal, and at the same time measure various other properties of that signal via a set of external scopes. You do this to ensure that your signal is in technical compliance with laws that govern TV signals in your region, and to help make color correction decisions.

You use a Mini Monitor to get a TV signal out of your grading app, then monitor that signal on a calibrated TV and a set of external scopes. Your signal is managed by the Mini Monitor, containing only your TV signal.

Plugging your monitor into the computer, you are seeing a signal generated by the graphics card containing other information managed by the OS. We don't want to "see" or monitor that. That's not what we are delivering.

Think of it this way: the Mini Monitor turns yours computer into a "TV station" of sorts. You use your calibrated TV to "watch" the TV signal "broadcast" by your computer-turned-TV station.

Same metaphor extends to grading movies. In this case, your UltraStudio or other monitoring device feeds a projector. Your computer then becomes a movie theater projector, and you watch it in a grading theater on a silver screen.

It's all about the signal.

[D Fosse]

It may be a "true TV signal", but how can he talk about color correction without any color correction? Or does he really believe that a mini monitor displays "correctly" out of the box, or even that two mini monitors will display identically? Of course they don't, and of course they won't.

[rodneyb56060189]

Thanks for your input. Are you saying this is philosophically unsound ? Or that a breakout box and capture/play cards, maybe with a loop, with an oscilloscope to test voltage ( IRE scale ) is necessary to fine tune it ??

??

[davescm]

Hi Dag

I've just read the article and it appears to be talking about the Black Magic Mini Monitor (or similar) which is not actually a monitor but a piece of hardware which generates TV signals from your computer. To be fair he does say those signals should then be monitored on a calibrated TV and [with] a set of external scopes.

Monitor calibration is as far as the video world go - and that does include black /white /greyscale and nowadays 3D color LUTs. I use Calman for that calibration.  The ICC profiling step that we then use in colour managed applications (such as Photoshop)  is not used in the video world.

So what he is suggesting is using a device that will take the "numbers "from the computer and generate a TV signal without any OS color management/correction - then view that signal on a calibrated video monitor (and external scopes) is the way to ensure accuracy of adjustment and correction for video.

Dave

[D Fosse]

OK, then I misunderstood a bit. Half-way there, calibration but no profile. Better than nothing.

I did know that's how the video world works. I have a range of emulations on my Eizo, including Rec.709 and DCI P3 (with practically full coverage), and I think they are quite accurate as such. Eizos are widely used in pro video.

But the precision level of a profile it can't match. That's why the profile is there, to pick up where the calibration stops.

[davescm]

https://forums.adobe.com/people/D+Fosse  wrote

I did know that's how the video world works.

I thought you would know Dag.  I added the extra paragraphs above for the benefit of anyone looking in (this being the Lounge).

Dave

[rodneyb56060189]

yes, thank you ! As a place to bring really smart people together to explain things to newcomers ( whatever their sources and products go to ) this is a really cool place ! Thank you so much !

As it happens I also ordered a 'field monitor' or 'reference monitor' to go along with the mini monitor card. That is calibrated I hope, and has some build in LUT's ( rec 709 etc. ) which hopefully will do some cool stuff when I use HDMI out from my graphics card ( using CS6 for example ) just to get a look at the TV signal. I have no clue if that will work yet until I install the card, drivers and see how CS6 interacts. Worse come to worse, I can put a clip into resolve, that I'm using in Ppro, ( just the color part of resolve) and see what I see re: Y, Cb, Cr. )  I have no clue what will happen cause I haven't installed it yet.

You are being so helpful and explaining things so well that I feel people who visit the lounge re: this subject will benefit tremendously from your expertise and experience with PPro and delivery !

Thank YOU !

[davescm]

rodneyb56060189  wrote

As it happens I also ordered a 'field monitor' or 'reference monitor' to go along with the mini monitor card. That is calibrated I hope.............

A monitor may have been calibrated at the factory but that does not take away the need for regular calibration going forward. If you are serious about colour, invest in the hardware and software to calibrate the monitor. For video that means test signals and a hardware device to measure the screen output - you cannot calibrate by eye.

For computer imagery - a calibration & profiling software package along with a hardware measurement device (e.g. i1Display).

Dave

[rodneyb56060189]

DOG DELIVERS TO DOG

The nice Fed Ex dog is on it's way to deliver BM card and reference monitor.

The apt. building I live in has a complicated 'buzzer' system and sometimes drivers don't know how to use it to contact tenants to get in building, and announce their arrival. Consequently, just like a dog waiting for it's owner to come home from work, I have my nose pressed to the glass window looking for the Fed Ex truck to pull into the parking lot.

I hope I can get this stuff to work with CS6. Investigations on internet have lead to nothing but confusion, contrary information, and a general sense that nobody in the world ( including manufacturers and software developers ) have a clue what is going on !

[rodneyb56060189]

1.30 pm MN. time, still got nose pinned to window. Mailman came, UPS came, no doggy delivery truck yet.

: (

[rodneyb56060189]

oh oh.

got doggy delivery. put card into pig ( not connected to internet since 2013 ). drivers wouldn't install for card (from little SD card sent by BM with card) due to some 'signing law which requires internet connection'. OMG. So, I moved router and now have about 20 yards of wires and cables intersecting my living room, and hooked up pig to internet. The pig is now required to download and install roughly 143 windows 7 pro updates, whereupon at some point some secret stuff will allow me to install the drivers from BM.

This could be the beginning of the END for the pig and win 7.  OMG !  All because I can't install little drivers from BM ( which by the way advertises some sort of 'game' stuff when you go to install drivers, which blows my mind ). Goodbye cruel world !

[rodneyb56060189]

I won't even TRY to explain what happened. Holy poop !

Finally got driver installed I guess ( cs6 has Blackmagic options now ). I now have 'unknown hardware' in machine ( aka mini monitor card) . I will try to connect it after I catch my breath a while, see if it actually WORKS. What a royal MESS that whole process was so far.

[rodneyb56060189]

Newest driver from BM worked, hardware recognized, cs6 has the info for setting up a project (playback, etc. ). Did fast experiment and got signal to ref monitor but black screen, sound coming through. Have to setup another project, try different monitor setup, and read instructions for new monitor. Made headway though ( in middle of night due to worrying over how to fix this stuff ). Hopefully next post will be about this SUBJECT of color stuff...

: )

[rodneyb56060189]

I guess I should mark this as answered or closed or whatever. I got the guts to get back into making another project in CS6 with new BM card, unchecked both my normal monitors and ONLY had BM checked for playback, and it worked great. Unfortunately, the image is WAY more contrasty than my computer monitors, so now it's a matter of learning and adjusting and using the tools. But the basic thing is happening. Got signal, got sound and video, and posted something in hardware forum in case anyone can shorten my learning process re: using the hardware correctly.

Thanks !

: )

[rodneyb56060189]

I'm going to order an Eizo monitor Sunday as D Fosse spoke highly of that brand.  I like the small 24" HD one, and can use either DVI-D or HDMI from graphics card. Looks like it has nice settings ( like rec 709, srgb or adobe rgb, etc. ). Earlier I checked my monitor(s) against ref monitor and also laptop and uploaded shot and quicktime and decided my primary monitor is junky.

I can use the 2nd just for some stuff like PPro panels I don't use that much and color doesn't matter. Make more room on 1st that way.

so, moving along.

: )

I noticed the Eizo has some software for calibrating, but I guess it needs a hardware device to stick on screen...any recommendations?

[D Fosse]

rodneyb56060189  wrote

I noticed the Eizo has some software for calibrating, but I guess it needs a hardware device to stick on screen...any recommendations?

The sensor is built in, in the higher end models - or you can buy an edition with separate sensor included.

Either way, the ColorNavigator software works fully integrated with the unit. All adjustments are done internally in the monitor - and then it writes an icc profile to use in color managed software.

[rodneyb56060189]

Thank you D Fosse. Yes, this thing has built in stuff, so I'll use that. Wasn't sure if it's good enough to rely on without external gadget. I shoot with a Nikon d800 dslr, using an atomos to record video via hdmi ( DNxHD). So I can probably use the default sRGB (web) and Adobe RGB (print), but if you do video, would you go with the default rec 709 or adjust it slightly ?

It's DNxHD 220X,  10 bit 4.2.2, 1920x1080, YUV, very basic stuff.

: )

[rodneyb56060189]

YIKES ! This stuff gets complicated fast !  I got my little ref monitor working well with SDI out from BM playback card, and then all my sound stuff went nuts for the computer when just trying to play mp3's and using headphones on computer case.  OMG !

Sound was getting routed to the ref monitor but when trying to use normal sound stuff on computer is was all messed up.

Whoever it was on the internet that gave me advice about settings in PPro about audio preferences and playback stuff should be whipped with a wet noodle !

[D Fosse]

I must admit I still have no idea what it is you're trying to accomplish here - especially not in the context of the thread title. Hopefully we get a "why" as this unfolds, in addition to the "how".

Whoever it was on the internet that gave me advice about settings

An old hand such as yourself obviously know that nothing you read on the internet can be taken at face value. Including this. In journalism it's called "source criticism", although it seems to have fallen on hard times lately...

[rodneyb56060189]

Is kinda complicated, my intent. On a personal level I simply want to finally (after many years) have a way to get very close (if not exactly match) to SEEING on my monitor(s) what is presumed to be the STANDARD (SMPTE) color and luminance, etc. for TV.

My belief is that as I adjust levels and color of my own shooting on those new color calibrated monitors and export the product, it will be very close to color etc. of TV standard.  In order to do this I figured I could use some advice and help and suggestions.

Fortunately people have ( like yourself ) been very helpful. Your mentioning the Eizo monitor you use prompted me to look into that monitor and it is arriving today.  I may have questions about setting that up properly later on.

ON a more universal level this thread might serve to help others who want to do something similar with their workflow in terms of getting the best representation of color for a reasonable price so that if they export things they can be assured they are exactly or very close to the TV SMPTE standard.

I haven't gotten into the nitty gritty of the actual IRE scale used in the past for CRT monitors and whether the new progressive TV signals have changed that 'range'.  I'll have to research that or maybe someone will chime in about what they know.

That's the purpose.

Yes, I know about the internet and need to sift through the stuff. It just seems to be worse than ever right now.

[rodneyb56060189]

When I think about 'nits' instead of IRE ( with log stuff today) I realize of course that this subject of color and standards may be a little too ambiguous and confusing with regard to a hobby. If there is some problem with this subject in the lounge, I am more than happy to have the entire thread deleted by those people who are able to manipulate the threads.

I've got what I need to start getting better at dealing with color and levels and scopes, etc., without regard to particular programs ( PPro, AE, Resolve, etc. ) for my own output and understanding. I know people who are currently shooting commercial stuff using all of the above and I can get info from the DIT people or DP to get what I need for info.

So, D Fosse, if you hate this thread, just delete it. Or whatever.

[D Fosse]

No, it's fine, I'm just curious.

I simply want to finally (after many years) have a way to get very close (if not exactly match) to SEEING on my monitor(s) what is presumed to be the STANDARD (SMPTE) color and luminance, etc. for TV.

And that's where I'm curious, because when I walk into a TV shop and look at the wall of screens, I'm not seeing much of any standard color and luminance...

[davescm]

Though most, out of the box, tend to come come adjusted somewhere between glaring and hideous, you can calibrate some TVs with varying degrees of accuracy depending on what adjustments you can gain access to.  Most allow adjustment of black point and white point. Many have greyscale tracking adjustment  and some give access to colour LUTs.  I use Calman software to calibrate mine at home.

Dave

[Michael J. Hoffman]

https://forums.adobe.com/people/D+Fosse  wrote

And that's where I'm curious, because when I walk into a TV shop and look at the wall of screens, I'm not seeing much of any standard color and luminance...

Funny you should mention that, because that is the exact example I give to my students to explain the need for calibrated monitors in a color-managed workflow. It’s something to which everyone can relate immediately.

Mike

[rodneyb56060189]

Got the Eizo monitor and it self calibrates the basic color spaces it comes with but when you add LUT (e.g. rec 709) it looks for a color calibration hardware ( like X-right etc.) So, ordered one.

So far the reference monitor (SDI out of BM) is cooler and more contrasty than the eizo cs2420.