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Discussion Starter · #1 ·
config:
standard issue 12" iBook G4.

Hooked up my proven calibrated Lacie elecrton blue III to it. The colour discrepency is phenomenal. I cannot seem to get any standard or custom profiles to make the monitors match up or even appear related. I knew the LCD was off, having to explain to clients that the light purple in my layout was actually a neutral grey, but now I realize how much it was off!

I've used gamma control to get the LCD in line. Some of the adjustments are pretty extreme. Way more that I think normal.

Anyone else have similar experiences?
Anyone think my LCD might be defective?
 

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hi there,

i have a 700mhz ibook and like yours my LCD is WAY off.
i have tried countless times to calibrate it with my ColorVision OptiCal spyder with no avail (even contacted ColorVision who werent much help).

my guess is that laptop LCD's just arent high quality enough to be colour accurate, and given that the ibook is intended to be for regular consumers, it shouldnt be a concern for apple.

while powerbook screens are MUCH better, ive noticed even on the 15" titaniums, the color is abit off.

what i do is just mirror my ibook display to a color calibrated CRT that i can trust....sometimes sucks especially when you want accuracy on the field but i guess you cant have it all.

hope this helps
(by the way i am a commercial photographer, so color accuracy is QUITE important!)

andy
 

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Fluorescent backlights cannot be calibrated properly and the blacks are awful. That's why Apple Canada continues to sell third party CRTs.
OLED may solve the problem but it's a ways off.

The other issue is that the LCD drifts over time. If you compare a new iBook screen with one that's even 6 months old the difference is quite remarkable.

For LCDs you can only really work by he numbers not what you see and keep a decent CRT around for accuracy. :cool:
 

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Ah, yes. MacDoc provides an Eureka!

There is no way a fluorescent lamp can be colour accurate because they glow in what is called a non-continuous spectrum. The maker chooses a mix of gases that each glow at a given colour temperature, and adds the spectrum up to approximate white light.

It's quite obvious if you view two lamps in the same fixture from different manufacturers; they will be noticeably different colours (because every lamp model uses a different mix of gases). When they're the same, our brains do a little re-calibration of their own (it always tries to make any light daylight-coloured, no matter what the actual colour of light it is. The obvious example is regular light bulbs which any photo reveals is really overly yellow, while we usually see them as white).

This also makes the colour very difficult to maintain with different ambient lighting conditions.

Incandescent lamps will display a continuous spectrum, but we don't use them in laptops.

It may well be that the particular lamp used in these powerbooks (and it's particular choice of gases/colours) is difficult to calibrate. There are special mixes of gas that display very close to daylight colours, but the lamps tend to run hotter so that might explain why laptops don't use them. The better lamps always cost more.

Perhaps minimal use of the backlight would allow a baseline calibration to be done. The calibration will change with every change in backlight level, though.

Every LCD display will exhibit the same issue to a certain extent when backlit.

[ January 30, 2004, 08:35 AM: Message edited by: gordguide ]
 

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Good deduction Gord - the only way pros were able to get close to accurate was to reduce the brightness level way way down which makes sense.
Philips has been working on a correctable tube for medical purposes but I would guess OLED ( or hope perhaps ) will correct these issues.

You would think perhaps two tubes with overlapping spectrums might work better and also allow a failsafe if one blows. If Barco can't get there for colour work I guess no one can. :cool:
 

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You can find better info on this subject, but this link * has some spectrographs of different FL tubes; note that these are premium tubes designed to mimic sunlight, yet they clearly show missing colours.

Less expensive tubes will be much worse. If you are using a backlight portable and viewing it under FL lighting, it's a worst-case nightmare of colour shifts.

What you will notice if you look at the colour charts are significant areas where these lamps produce no light whatsoever between ultraviolet and infared (ie the spectra area is black) as well as many areas where they produce narrow, bright areas of colour. This is essentially uncalibrateable light. Even the best examples show very bright and narrow violet and green spectra.

The incandescent bulb may begin somewhere on the blue scale and end somewhere on the red scale, but in between it will look just like the sunlight chart (even energy, no gaps).

Completely off-topic, but the comparison between FL and natural light is very much a workable analogy for thinking about the difference between digital audio and analog audio.

* Checking the URL reveals it doesn't direct to the right page; when you get there go to the link:
Fluorescent Light Comparison
... on that page.

[ January 31, 2004, 04:28 AM: Message edited by: gordguide ]
 

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Discussion Starter · #7 ·
thanks for edtailed spectrum analaysis, gordguide. I had really never thought about the nature of the backlight and am surprised to hear it's fluorescent.

I have also found that lowering the brightness on my iBook allows me to calibrate it within reason using Gamma Control 2.0. I was a little worried I might have had a defective unit, because running the built-in colour calibration utility always garnered colour casts in the screen.

I'm also surprised to hear that the spyder didn't help prsphoto.

Are powerbook screens really that much better than iBook screens? I was under the impression that the 12" models both employed the same screen. Was I misinformed?
 

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LCDs were the "big lie" foisted on the tech buying public. And they bought it hook line and sinker.

They were NOT better technology. Just like plasma is being touted in HDTV.
New is not always better.

LCDs are a necessary evil on portables. They don't have to be on your desk.

Anyone for a DLP desktop screen. :eek:
 

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Oh Macdoc... give it a rest. Really! :rolleyes: Do we really have to go through this AGAIN? I know dozens of very high end, professional photographers and designers who use LCD for colour critical work.

This argument It's gotten to the point of silly.

avalonian and prsphoto, try
SuperCal.

Read the reviews on the link above if you don't believe me. Apple should bundle this app.

Supercal is an application that can accurately correct monitor response curves using only visual tests. Unlike most calibration applications, no assumptions are made about the display's response curves, so it can make highly accurate and detailed corrections for any display technology (CRT, LCD, DLP, Plasma, etc.) used in desktop, wall mount, and projection systems. Using only your eye as the measuring device, this program is capable of producing a very neutral gray ramp. In addition, profiles with different target gamma and white balance settings can be created without repeating the entire calibration process.

------

And please don't lump in laptop LCD displays in with all LCD displays like Apple's Cinema displays. There is a BIG difference in the backlight and viewing angle on them.

Really, if I hear your BIG LIE one more time Macdoc, I'm going to clobber you over the head with a virtual 20" CRT. :mad:

[ January 31, 2004, 10:44 PM: Message edited by: ehMax ]
 

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"If Barco can't get there for colour work I guess no one can."

Well lookie, lookie. In a follow up to this post I made, look what Barco just announced 3 days ago. :D



“With the introduction of the innovative COLORIS CALIBRATOR®, Barco has managed to successfully unite the unarguable advantages of compact LCD technology with high-standing color accuracy and consistency required in color critical environments. We are confident that graphics professionals will welcome this important innovation in color imaging technology”, stated Luc Vandenbroucke, Senior Vice-President Barco and President BarcoView.

Can we PLEASE put this LCD is not good for colour crap finally to rest now?!?!


[ February 01, 2004, 12:35 AM: Message edited by: ehMax ]
 
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