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Display Calibration Light Illusion Forums / Display Calibration /  
 

Basic questions about calibration

 
Author Mihai Nicolau
ZRO
#1 | Posted: 17 May 2012 22:06 
Hello,

I have some questions about basic monitor calibrating procedures. I'm new in this field but an avid learner so if the answers might be too long or complicated please point me in the right direction (links, whitepapers anything).
So here goes (I'm talking about calibrating some simple "non grading" monitors, I own 2 Dell monitors with IPS panels, not the cheapest not the best, standard sRGB gamut:
1) As I understand calibrating a monitor with a probe just brings that particular screen to some known standards (gamma, screen brightness, color temperature). Does it also recalibrate the color space, in my case probably sRGB to be more accurate ?
2) After calibrating I need a piece of software like Lightspace ot generate LUTs for different color spaces ? Can this be done at all on a "normal" monitor as I see that you also have the ICC software which converts LUTs into ICC profiles.
3) Can a monitor be made to emulate, and can you trust up to a point this emulation, a much larger color space than it is capable of ? Like the XYZ colorspace ?
4) What exactly affects the ability of a monitor to display a particular dynamic range ? I've read that the higher end ones have a high bit depth, about 10 or even 12 internal LUT. Does this affect dinamyc range or just the number of tones that screen can reproduce therefore reducing banding and other bad stuff ?
It is my understanding that current monitors can only reproduce about 10 stops of dynamic range ? Is it also because of this that the high end digital cameras need to employ elaborate gamma curves to cram all that info to show it up on these screens ? Would having a high latitude screen as a standard eliminate this need ?
5) Is an HP Dreamcolor a good beginning choice for good and accurate monitoring ? Are there other better solutions at the same pricepoint ?
6) For somebody who uses After Effects or even Photoshop. After Effects has some emulations, or LUTs don t know how to call them for showing different spaces of color. If I have a calibrated monitor (using a probe) can I select one of these spaces (709 for example) and be all set ? Is it that easy ? Photoshop also has a ton of profiles, including video and even film stocks ones. Is this as simple as calibrating one's monitor and then just applyling a profile ?

Thank you,
Mike

Author Steve

INF
Male
#2 | Posted: 18 May 2012 09:43 
Hi Mike,

1 - basic PC or Mac based profiling only sets grey scale / white point. It has no control over Gamut. Brightness should be set manually. So no, it doesn't set colour space. See my post on ICC profiles.

2 - LightSpace builds LUT for full display calibration, but only if the display or system in use can work with LUTs. Most displays can't. See Penta Monitors for ones that can as an example.

3 - Monitors can only ever be calibrated to specification below their own maximum capabilities - very, very few displays can do P3, and none can do XYZ (but XYZ is NOT a display colour space as such - it is based on P3)

4 - The underlying screen defines all capabilities - colour space and dynamic range. This can't be improved other than by building a better display screen. Bit depth only changes the 'steps' between the min and max a given screen can work with - exactly as you say.

5 - normal TV definitions define what we work with in post - what you can see at home has to define the displays used in post-production. It's no good having a huge range that can be seen in post, as it will never look right when broadcast. If home TV change spec from SMPTE/Rec709 then post can change too...

6 - The pre-sets in AE and PhotoShop (ICC profiles) are not guaranteed accurate, and use the ICC concept of source and target profiles in partnership. Thsi is very different to the LUT based workflow we use in the broadcast and film industry - again see my post on ICC profiles.I have never found the pre-sets to be accurate enough.

Hope this helps.
Steve Shaw
Mob Boss at Light Illusion

Author Mihai Nicolau
ZRO
#3 | Posted: 20 May 2012 11:22 
Hello Steve,

Yes this clears a lot of things in my mind thank you.

1) I'm not sure where I can find your post regarding ICC, is it here in the forum or on a specific link in the website ? EDIT: Found it.

2) I also asked about the HP Dreamcolor monitor, if it is a good choice as a cheap starting point in monitoring work ? And seeing as you mentioned P3, it says on its specs that it can emulate P3.

3) Is this the page for the Penta monitors ? http://www.hd2line.com/

I'll read about the ICC stuff and come back if I have any more questions.
Thanks again,
Mike

Author Steve

INF
Male
#4 | Posted: 20 May 2012 11:26 
Hi Mike,

See here: http://www.lightillusion.com/forums/index.php?action=vthread&forum=8&topic=28

And I don't like the Dreamcolor - not worth the money, and CAN'T accurately do P3.
It's biggest problem tends to be uneven colour across the screen, which you can't correct with calibration.
Steve Shaw
Mob Boss at Light Illusion

Author Mihai Nicolau
ZRO
#5 | Posted: 20 May 2012 12:43 
So then, what would be your recommendation for about the same price point ?

Author Steve

INF
Male
#6 | Posted: 20 May 2012 12:49 
There's no simple answer to that.
Do you want HDSDI input, or just HDMI/DVI?

We have been using Penta monitors a fair bit recently, although a lot of people seem to like Plasmas.
The problem with Plasmas is their power-save mode...
Steve Shaw
Mob Boss at Light Illusion

Author Mihai Nicolau
ZRO
#7 | Posted: 20 May 2012 17:21 
Well,

I'm not sure. SDI is more professional and robust and probably better in terms of the signals it supports and this being the 3rd monitor in my configuration it wouldn't be possible to connect it through another HDMI/DVI/DisplayPort cable since my graphics card only supports 2 simultaneous inputs.
So I'll probably have to also buy a capture card so I can drive it. Anyway I've seen this is the best config for a grading configuration, 3 monitors, 1 for GUI 1 for scopes and one for reference.
Plasmas are good but waaay to big for me right now. I was thinking about a 24" size or bigger, but not much bigger.
And what is the power save mode problem with plasmas ?
Thanks.

Author Steve

INF
Male
#8 | Posted: 20 May 2012 17:44 
All Plasmas have a 'power save' mode that drops the power to the screen as the screen brightness increases...
This can't be turned off on any Plasma.

This make them very difficult to use for real grading, especially if the material is overall bright - natural history in a desert, for example.
Steve Shaw
Mob Boss at Light Illusion

Author Mihai Nicolau
ZRO
#9 | Posted: 20 May 2012 17:49 
Didn't know that thanks for the info, let me know if you have any suggestions for a good monitor.

thanks.

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