Ad
Ad
Ad
Pages: « 1 [2]   Bottom of Page
Print
Author Topic: Calibrate LCD to 6500 or native white point?  (Read 12216 times)
digitaldog
Sr. Member
****
Offline Offline

Posts: 9315



WWW
« Reply #20 on: May 11, 2006, 07:36:03 PM »
ReplyReply

Quote
I admit I don't understand this statement.
[a href=\"index.php?act=findpost&pid=65152\"][{POST_SNAPBACK}][/a]

Try this:

Create a new document in Photoshop. The size isn’t critical but try to make
the horizontal about 1200 pixels. You want to view as much of
this document at 100% zoom ratio in Photoshop filling most of
the display you are testing. The color space of the document
isn’t important.

2. Choose Edit-Fill and when the Fill dialog appears select Use:
Black, BlendingMode: Normal, Opacity 100%.

3. Choose Image-Mode-Assign Profile in Photoshop CS or
Edit-Assign Profile in CS2. From the list of profiles you need
to select your display profile. What this does is ensure that
Photoshop will simply send the numbers in this document
directly to the screen. This will aid in evaluating the display
profile.

4. You will need to select the Rectangle Marquee from the
Photoshop toolbar or simply hold down the M key. Make sure
that in the option bar the Feather is set to zero and that the
Style: pop-up menu is set to Normal.

5. You will need to make a rectangle selection in this document. It
can be just about any size but try and make it so it fills about 50 percent
of the document in the center. You will need to be able to see inside and outside
of this marquee so don’t make it too large or too tiny.

6. Hide the marching ants. This can be done by selecting View-
Show-None or by holding down the Command/Control H
key.

7. At this point, You need to fill the entire display with this black
document so we need to go into full screen mode. The easiest
way to do this is to press the F key twice. Hide the tool bar and palettes. By holding down the Tab key,
 
8. At this point, you should have a screen filled with only black!
You we need to call up the Curves command. Since the
menus are hidden, you’ll need to use the Key command,
which is Command/Control M. The curves dialog should
appear. Move it over to a corner since you will want to see the
effect of the hidden rectangle marquee.

9. At this point, you will move the black curve point up one
numeric value at a time. To do this, simply press the up arrow
key on your keyboard once. The output value will change from
zero to 1. If instead the values pops up to 2, enter 1 into this
output field and all subsequent pressing on the up arrow will
ensure only one value is added. Keep pressing this up arrow
key until you can just see the separation from the rectangle
marquee. That is, you want to just barely see the rectangle. You
may need to press the up arrow key several times. Ideally, you
want to see separation between a value of 0 and 1. I can see
this on the Artisan.

Keep moving the up arrow slowly once you see the separation.
The next thing you want to do is examine how neutral each
step is. Not only should each step show the same density
difference from the last, but also each progressively gray step
should be neutral. It is not uncommon to see a gray square go
from neutral, to slightly green, to slightly magenta, and back  but that's NOT ideal.
Logged

Andrew Rodney
Author “Color Management for Photographers”
http://digitaldog.net/
Stephen Best
Guest
« Reply #21 on: May 11, 2006, 08:17:58 PM »
ReplyReply

Some ready-made files people may find helpful for determining display/print neutrality and black separation:

http://www.macquarieeditions.com.au/misc/RGBGrays.tif
http://www.macquarieeditions.com.au/misc/LABGrays.tif
http://www.macquarieeditions.com.au/misc/Blacks.tif

For the RGB files, any profile (display or working space) can be assigned. The first two I think I found on Bill Atkinson's site.
Logged
Serge Cashman
Full Member
***
Offline Offline

Posts: 200


« Reply #22 on: May 11, 2006, 08:48:56 PM »
ReplyReply

Thank you Andrew. I feel like this theoretical discussion kind of hijacks the thread even though I'm extremely interested in it. The original question  of if it's possible to losslessly calibrate a 12 bit LUTs NEC 2090uxi   to any white point and gamma (and how to do it) is still open.


Since I am really interested in this kind of tests I went ahead and ran it (it's easier with two monitors). Obviously a Dell LCD is not an Artisan and Spyder2 is not  Coloreyes+Xrite. So yes I only see differences starting from 7 and yes I see very perceptible differences in tint going through the shades of grey.

However... As far as the controls I have over the calibration the White Point Target is the only control I have that affects neutrality.  So even if it works imperfectly there's not much I can do to change that.

One more thing I am not clear about - why look at the test images in monitor profile? It essentially simulates non-colormanaged applications, correct?

I don't know what to look for in the last two of Stephen's images - I know my greyscale ramps are not perfect but tolerable.
Logged
Stephen Best
Guest
« Reply #23 on: May 11, 2006, 10:06:45 PM »
ReplyReply

Quote
One more thing I am not clear about - why look at the test images in monitor profile? It essentially simulates non-colormanaged applications, correct?
[a href=\"index.php?act=findpost&pid=65160\"][{POST_SNAPBACK}][/a]

Andrew is more capable of answering this but, as I understand it, the intention is to take the monitor profile out of the picture so you're looking at separation and neutrality of the display by itself. The less work the LUT in the display card has to do, the better.

As for the files I referenced, you can use these in a number of ways. The LABGrays (and RGBGrays) file is useful for assessing monitor profiles. Better profiling packages will generate profiles that are more neutral (look cleaner) and smoother (less banding) but this is just one criterion for evaluation. The Blacks file can show you if and where your shadows are blocked, both on display and in the print. Note that the distribution will change with the gamma of the assigned working space. Have a play around with a number of monitors and profiles to get a feel for what these are telling you.
Logged
marc.s
Jr. Member
**
Offline Offline

Posts: 91


« Reply #24 on: May 11, 2006, 10:45:03 PM »
ReplyReply

I wrote the post in dpreview quoting Alexander Klein. I got the same reply from the basICColor team, so I assume it's correct. I therefore have been wondering about the purpose of the 12bit LUT as well for the models that do not have the proper firmware for DDC.

I'm personally waiting for the SpectraView 2090 model to be released so I can compare prices to the 2090uxi, but it will probably be too expensive for me.

Since Nill has only said good things about the regular version I'm not too worried though
Logged
Serge Cashman
Full Member
***
Offline Offline

Posts: 200


« Reply #25 on: May 14, 2006, 05:35:58 PM »
ReplyReply

Marc, this is interesting.  I am convinced there's gotta be more value in this monitor than a typical LCD. It's surprising how little information is available.

Stephen, thanks for the explanation. I think Photoshop does not affect the LUTs though. I'll experiment with your files some more.
Logged
nickynick
Newbie
*
Offline Offline

Posts: 1


« Reply #26 on: May 15, 2006, 04:40:57 AM »
ReplyReply

Quote
Marc, this is interesting.  I am convinced there's gotta be more value in this monitor than a typical LCD. It's surprising how little information is available.

Stephen, thanks for the explanation. I think Photoshop does not affect the LUTs though. I'll experiment with your files some more.
[a href=\"index.php?act=findpost&pid=65458\"][{POST_SNAPBACK}][/a]

The confusion about the 1990SXi/2090UXi/2190UXi being hardware calibratable over DDC with the Spectraview stems from different NEC policies in Europe vs US:

- The US Spectraview II software is completely different from the European Spectraview Profiler 4 software. The latter is an OEM version of basICColor, while the former is developped by NEC US.
- European and US versions of the 9 series displays have different firmware tags, so that hardware calibration software can discern them.
- In Europe, the Spectraview Profiler software is only sold in the Spectraview packages. The displays in the Spectraview packages has a different firmware tag then the non-Spectraview ones. The Spectraview Profiler refuses to hardware calibrate the displays that don't have the European Spectraview tag in their firmware (so it also refuses the US models). This is all due to recent change in the NEC Europe policy. The company making Spectraview Profiler is no longer allowed to release a version of its own software, basICColor, that is capable of hardware calibrating the non-Spectraview 9 series (and not even the old 8 series).
- In US, the Spectraview II software can be bought separately and is supposed to hardware calibrate the non-spectraview 9 series displays (= the ones not sold in a Spectraview package. However, the latest version is not released yet, so it's not clear if that policy will be maintained.
Logged
Nill Toulme
Sr. Member
****
Offline Offline

Posts: 741



WWW
« Reply #27 on: May 15, 2006, 09:42:01 AM »
ReplyReply

Quote
- In US, the Spectraview II software can be bought separately and is supposed to hardware calibrate the non-spectraview 9 series displays (= the ones not sold in a Spectraview package. However, the latest version is not released yet, so it's not clear if that policy will be maintained.
[{POST_SNAPBACK}][/a]
Interesting and helpful, thanks.  Based on my recent exchanges with US NEC support, it seems likely that the policy you describe will be maintained.  They're still predicting release of the new version of Spectraview II later this month.

Nill
~~
[a href=\"http://www.toulme.net]www.toulme.net[/url]
Logged
marc.s
Jr. Member
**
Offline Offline

Posts: 91


« Reply #28 on: May 15, 2006, 02:16:51 PM »
ReplyReply

Great, so people in the US get to DDC calibrate with the regular monitors while us in Europe have to pay through the nose for the SpectraView version of the monitors?

That sucks.
Logged
Nill Toulme
Sr. Member
****
Offline Offline

Posts: 741



WWW
« Reply #29 on: May 15, 2006, 03:44:33 PM »
ReplyReply

Quote
Well maybe, maybe not.  As I recall the SV versions include both the software and the hood.  Those two things add up to an additional 320 clams or so in the US, so unless the EU price delta between the SV and non-SV versions is a lot more than that, it's a wash — other than the fact that there's no "upgrade" path for non-SV owners I suppose.

I wonder what keeps a European customer from using the US software?

Nill
~~
[a href=\"http://www.toulme.net]www.toulme.net[/url]
« Last Edit: May 15, 2006, 03:46:05 PM by Nill Toulme » Logged
marc.s
Jr. Member
**
Offline Offline

Posts: 91


« Reply #30 on: May 15, 2006, 10:18:27 PM »
ReplyReply

I can make myself a cheap hood, and the price difference between the two monitors here is 500 usd while I could pick up the software for less than 200.. since I'm already stretching the budget it's not so fun for me.

Quote
I wonder what keeps a European customer from using the US software?

Well, since the firmware in the European 2090uxi is different from what I understood there's no point getting the US software since it won't DDC with the altered firmware.
Logged
Pages: « 1 [2]   Top of Page
Print
Jump to:  

Ad
Ad
Ad