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Author Topic: HP LP2475w calibration from scratch  (Read 41681 times)
digitaldog
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« Reply #20 on: January 08, 2009, 03:47:45 PM »
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Quote from: Damo77
From my own experience, and the evidence of thousands of forum posts.  Not a day goes by without somebody saying "Help! My prints are too dark!", and the source of the problem being traced to a too-bright monitor.

Look, I know you're the expert (and how!) but I think you're losing the common touch.  This talk of "140-150 and go up from there", while it may be scientifically correct, is impractical and is likely to cause humble photographers a great deal of grief and wasted prints.

I don't see people having any issues matching screen to print with these display luminance plus, greatly reduced LCD luminance is of questionable usefulness if any.

People who say their prints are too dark also have to tell us how they are viewing the prints and if its controllable (which it should be), can you up that luminance and maintain the color?

140cd/m2 is the lower end of what these devices can hit. Dimming them further by using LUTs isn't really useful.

The optimal max ambient light with a display at 90cd/m2 is roughly 16-20 candela which is mightily dim.
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Andrew Rodney
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Tim Lookingbill
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« Reply #21 on: January 08, 2009, 04:08:12 PM »
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I don't know why Andrew would advocate that high of a luminance either.

I've got my iMac calibrated around 90 cd/m2 and my prints match my monitor perfectly. But I do have all my windows covered by curtains and have only one light source on, a 620 lumins GE Sunshine fluorescent T8. I do have to put my prints directly under this light to have them match my monitor. I've raised the luminance of my iMac which maxes out at about 250 cd/m2 and putting it at 120 is blindingly bright and hurts my eyes after a while.
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Damo77
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« Reply #22 on: January 08, 2009, 04:29:47 PM »
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Quote from: digitaldog
140cd/m2 is the lower end of what these devices can hit. Dimming them further by using LUTs isn't really useful.
Like I say, it's hard to ignore the countless threads of evidence to the contrary.  I'd say it's very useful, both in terms of real-world print matching (as opposed to "I can afford to spend oodles of money turning my office into a colour-scientist-approved viewing environment" print matching), and eye strain, as tlooknbill mentioned.
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Damien
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« Reply #23 on: January 08, 2009, 06:47:58 PM »
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You can run your display that high but then you'ld have to match it with equal ambient light and since you can't rely on your window light due to the variances throughout the day and into the night, you'll have to equip the room with probably 2-4, 80 watt 4 foot fluorescent T12 tubes depending on room size.

Those are some bright lights for a studio.
« Last Edit: January 08, 2009, 06:48:52 PM by tlooknbill » Logged
Gupfold
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« Reply #24 on: January 08, 2009, 11:29:25 PM »
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Since Calibrating to 120, I have had to go back down to what I find a more comfortable 100. 120 seemed to bright after a while and I feel like I have to squint when I look at lots of white. 100 still gives me the best match to the brightness of prints, in "normal viewing conditions". I still have a little banding but only noticeable if the gradient is very wide, banding is fairly evenly spread but very slight. I feel I am better off with a little banding than with too bright a screen.
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Damo77
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« Reply #25 on: January 08, 2009, 11:44:21 PM »
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Quote from: Gupfold
I feel I am better off with a little banding than with too bright a screen.
I agree.

Glad to hear you've achieved a satisfactory calibration.  Happy new year!
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Damien
Gupfold
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« Reply #26 on: January 09, 2009, 03:32:11 AM »
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Do the Lacie and NEC Monitors also show banding like this after calibration, is this normal for a LCD like the HP LP2475w.

Isnt trying to match a print to a screen under a light booth with 500 - 2000 lux lighting not very productive as the print will probably never actually be viewed under such bright light or even that 5000K colour light. Is that just to have a standard, if so why would they suggest such a bright standard?
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digitaldog
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« Reply #27 on: January 09, 2009, 09:02:59 AM »
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Quote from: Gupfold
Isnt trying to match a print to a screen under a light booth with 500 - 2000 lux lighting not very productive as the print will probably never actually be viewed under such bright light or even that 5000K colour light. Is that just to have a standard, if so why would they suggest such a bright standard?

Doesn't matter. The idea, at least initially is to ensure that the print and screen match, you can't even evaluate that possibility without having a viewing booth next to the display!

OK, lets say you do have a match. Great. You know what you see is what you get in this reference environment,. IF you want to match to another environment, you can and should (down to building a custom profile with the measured illuminant for the custom white point). You can produce a print that's lovely, but you can't say it necessary matches the display!


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Andrew Rodney
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NashvilleMike
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« Reply #28 on: January 09, 2009, 12:20:56 PM »
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Quote from: Gupfold
Do the Lacie and NEC Monitors also show banding like this after calibration, is this normal for a LCD like the HP LP2475w.

I have an NEC 2490 that I run a bit dim (100 cd/m2 at 6250K and 2.2) and I've never had any banding issues with the NEC. So it might be an issue with the HP monitor, or perhaps something else is going on.

What is frustrating, at least for me, is having to buy the monitors "blind".  I wish there would have been a place locally where I could have seen, say, the Eizo CE and CG 24" as well as the NEC 24" monitors side by side to compare. I like the NEC, quite a bit actually, but I also don't think it's quite as excellent as some reviewers have made it out to be either.

-m
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sandymc
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« Reply #29 on: January 09, 2009, 02:22:49 PM »
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For what its worth I have a 2475, which I calibrate via an Eye One. I have it set to brightness of 19, R 225, G 200, B 224. That's brighter than the recommended 100-120, but I found that uniformity was better at the higher level, and anyway I have a bright work area. I can't see any banding on my display.

Sandy
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Gupfold
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« Reply #30 on: January 09, 2009, 02:45:04 PM »
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Quote from: digitaldog
OK, lets say you do have a match. Great. You know what you see is what you get in this reference environment,. IF you want to match to another environment, you can and should (down to building a custom profile with the measured illuminant for the custom white point). You can produce a print that's lovely, but you can't say it necessary matches the display!

Excuse me if my questions sound ignorant, but these forums offer a very nice opportunity for me to learn from more experienced and knowledgeable people.

Yes thats what I mean, A print under a 5000K viewing booth at 500 lux that matches the display is most likely going to look very different where it is finally displayed as very few houses, galleries etc have 5000K, 500 lux lighting, I battle to even find any 5000K fl tubes. So would it not be better to have a viewing booth that is 'more likely' to match the final viewing lighting, like cool white, or warm white which are readily available or a mix of these at lower lux levels? If 5000K is not your typical lighting why would this be a standard?

Sandy, mine is also more uniform when 120 or higher but in my office I find it too bright, the banding I see at 100 is very slight and in any real images I have never seen it, so far I am very happy with it.
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digitaldog
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« Reply #31 on: January 09, 2009, 02:52:47 PM »
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Quote from: Gupfold
A print under a 5000K viewing booth at 500 lux that matches the display is most likely going to look very different where it is finally displayed

I'm not so sure. Other than the fact we're working with digital files, we've been making prints for decades that don't necessarily match under differing illuminants. The Ciba's I made in the lab and examined there looked fine in my home, the lighting was totally different too.

I wasn't trying to match the print to anything and unless you're viewing the print and display in a context that proves that you've got a match, its immaterial. The print from here isn't chopped liver because you took it elsewhere to view. It probably doesn't appear the same as when you viewed it by the display. You don't know this, you're not viewing them at the same time. Our eyes adapt to white (one reason why print to display matching ain't easy).

There's two issues here. One is making a print and display match. That tells us something really useful about our color management system. The other is making a print that looks as you expect away from that environment. When the print and display match (you've edited the file as desired), the print should look just fine elsewhere (within reason).
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Andrew Rodney
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« Reply #32 on: January 10, 2009, 11:31:06 AM »
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Quote from: digitaldog
There's two issues here. One is making a print and display match. That tells us something really useful about our color management system. The other is making a print that looks as you expect away from that environment. When the print and display match (you've edited the file as desired), the print should look just fine elsewhere (within reason).

Thanks for putting up with my questions. I agree and understand this, I was just questioning or rather wondering why 5000K and 500 or 2000 lux were chosen as a standard to view prints under, is it just because this colour gives a reasonable match to screen or is it similar to most viewing enviroments or both.
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digitaldog
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« Reply #33 on: January 10, 2009, 12:07:13 PM »
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Quote from: Gupfold
Thanks for putting up with my questions. I agree and understand this, I was just questioning or rather wondering why 5000K and 500 or 2000 lux were chosen as a standard to view prints under, is it just because this colour gives a reasonable match to screen or is it similar to most viewing enviroments or both.

I don't know they are standards. In fact, if you refer to what are somewhat standards (ISO ISO 3664:2000 specifications: Viewing Conditions - for Graphic Technology and Photography), its an old such standard, developed around the old CRT technology and in need of an update.

5000K isn't the right answer, all the time. In fact, I'd prefer if specifying color would not use K (or correlated color temp) but rather using a standard illuminant (D50). D50 and 5000K are not the same. Lots of colors correlate to 5000K but there's only one color at D50.
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Andrew Rodney
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Tim Lookingbill
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« Reply #34 on: January 10, 2009, 01:34:49 PM »
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I can confirm what Andrew says about the meaning and appearance of Kelvin (K) and how it makes prints look under these types of so called full spectrum lights. Each manufacturer of claimed 5000K lighting show slight differences within the same number between them but it's quite subtle and in fact not worth being concerned about because of other variables such as limitation of color gamuts among different output devices.

The differences between the appearance of different Kelvin rated lighting isn't that noticeable either with prints as long as you stay within 4700K-6000K. I've investigated four brands of print viewing lights that fall between these Kelvin numbers, 5000K GE Sunshine fluorescent tube, 4700K Solux MR6 halogen, 5900K BlueMax CFL and the 5500K Ottlight CFL. The GE and the Solux only show slight differences between each with Solux retaining correct looking saturation/hue in warm colors better than the GE, the Ottlight looks bluer and the BlueMax looks closer to the GE's with quite a bit more noticeable greenish yellow even though it's suppose to be 5900K.  

As long as prints look close to neutral under these lights by viewing a grayramp or B&W print and make colors look good which is the most important, it shouldn't be a problem. You'll never exactly match with split hair precision your prints to your display under these lights, but if you can make them look good, you'll be fine.

Below is a comparison shot of two prints of standard color targets with the CMYK target (Ole No Moire) on the left and an Epson 2200 inkjet (PDI target) on the right viewed under two different lights with Kelvin ratings far apart from each other. What you are seeing is exactly how these prints look under these lights. Please view in a color managed app.

[attachment=10835:SoluxVSO..._CMYK_LL.jpg]
« Last Edit: January 10, 2009, 01:38:24 PM by tlooknbill » Logged
digitaldog
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« Reply #35 on: January 10, 2009, 03:35:11 PM »
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Quote from: tlooknbill
Below is a comparison shot of two prints of standard color targets with the CMYK target (Ole No Moire) on the left and an Epson 2200 inkjet (PDI target) on the right viewed under two different lights with Kelvin ratings far apart from each other. What you are seeing is exactly how these prints look under these lights. Please view in a color managed app.

Solux looks way more better <g>
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Andrew Rodney
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Gupfold
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« Reply #36 on: January 10, 2009, 10:41:01 PM »
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Thanks for all the answers and time. Learning would be a far more difficult process without these forums.
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trinityss
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« Reply #37 on: January 11, 2009, 08:01:41 AM »
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If i compare images (sRGB) from the KODAK Color Management Check-up kit in Photoshop on my HP LP2475w display with the prints from that kit under the OttLight (i measure 5600K) then they look warmer, the grey on my display is more reddish / warmer. My monitor is calibrated towards 6500 / gamma 2.2 / 120 cd/m˛.

Should i keep the 6500K as white point on my monitor or go for 5600K? But then i'm making my white point more warmer...

sRGB and AdobeRGB have both D65 as white point, does this mean that my monitor white point also must be D65 in any circumstances?


Kr,
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digitaldog
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« Reply #38 on: January 11, 2009, 09:47:19 AM »
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Quote from: trinityss
Should i keep the 6500K as white point on my monitor or go for 5600K? But then i'm making my white point more warmer...

IF that results in a match fine. BTW, what did you measure the Ottlight with? As for 6500K, did you look at the spectrum?

Quote
sRGB and AdobeRGB have both D65 as white point, does this mean that my monitor white point also must be D65 in any circumstances?

Working space specifications and display target calibration aim points are separate, don't have to match.
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Andrew Rodney
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trinityss
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« Reply #39 on: January 11, 2009, 02:52:03 PM »
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Quote from: digitaldog
IF that results in a match fine. BTW, what did you measure the Ottlight with? As for 6500K, did you look at the spectrum?

Hi digitaldog, thanks for your reply!

Ok, then i'll try to match the white point of my Ottlight. Let's see if the greys are more neutral then...
I'm measuring it with my EyeOne display2 in Eye-One match.
[attachment=10839:ott.jpg]

But then my white point is not as recommended in the ISO3664?
[attachment=10841:ISO3364_...SO_12646.jpg]
source: http://www.creativepro.com/article/the-dar...omeback-part-2-

I'm a little bit "white point" confused.
So i don't need to worry about the white point of working spaces, and it's allowed to have a white point more close to that of my ambient light/ottlight.
But then i don't meet the ISO3664...

Eventually i want to achieve what is specified in the ISO and have a good match between my prints and monitor.
I was hoping that it was possible with this HP monitor...


Your question about the spectrum of the 6500K, did you mean the the spectrum of the white point of my monitor after calibrating towards 6500K?
If that is the case, i think this is only possible when i would have an eye one Pro and Eye-One Share...?

Kr,
« Last Edit: January 11, 2009, 02:54:28 PM by trinityss » Logged
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