Monitor underexposing...

kman

kman

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Hi,

I have noticed an issue with my desktop pc monitor (Dell U2410) which is colour calibrated (with an i1) and that is that images appear more underexposed than they really are.

The best way to explain this is with an example image.

Here is an image where I have used LR to just paint some exposure reduction in (using the adjustment brush) across the face (under the glasses).

facegc.jpg


Now on my Dell screen its virtually pure black - you can't make out any details of the mouth, nose etc. However the same image on my laptop (also calibrated) you can clearly see under the painted area, the lips, nose, stubble etc.

I'm a bit confused as to why this is happening and what I can do about it - switching colour profiles doesn't seem to do anything nor does playing with monitor contrast/brightness settings etc.

Any ideas? Can you all see the details of the face as well? Do I need to calibrate to a different luminosity?
 
On my Eizo it looks black.

On my MacBook Pro, I can just about make out a nose and mouth (barely).

Both calibrated.

However, it may just be the slight difference in angle of view, as if I move my head to the side of the Eizo, the nose and mouth become just (very just) visible. Adjust the MBP to be slightly more square on than it was and I can't see it.

Stand up and look at the MBP at a steep angle (which makes the on-screen image on the MBP bluer due to the angle) and the face becomes clearly visible. Crouch down a bit (it heads toward magenta) and it disappears entirely.

In either case, calibration doesn't guarantee exact matching across different displays, just a best match. In marginal cases like this, then there may still be a difference.
 
The issue is that on the Dell monitor it looks black regardless of the angle you look at it. Therefore I don't think its an issue to do with how the monitor performs under different viewing angles - in general I'm looking at the monitor straight on and it doesn't make a difference in terms of lighting conditions either.

With the laptop and its limited viewing angles, yes you can make it look black but only in extreme viewing angles or tilted angles. Straight on I can make out details under the painted areas where I clearly see where two teeth are, lips,the line of stubble, the crease lines where I'm slightly smiling, the nostrils and the nose shape etc...none of which is visible on the PC monitor.
 
Don't confuse colour calibration with brightness calibration. Does your calibrator measure the luminance of the screen (cd/m^2)? If so do both of your monitor have the same luminance?
 
Kev M said:
Don't confuse colour calibration with brightness calibration. Does your calibrator measure the luminance of the screen (cd/m^2)? If so do both of your monitor have the same luminance?
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Yes it does and I don't know what luminance settings I've calibrated it too. Does the luminance need to be set lower on the PC monitor to stop it from underexposing too much?
 
I'm going to rerun the calibration on both machines in the same room now and try to match the luminance as well.
 
Another quick question - what should the gamma settings be on the monitor? I've noticed I get more detail out by dropping the gamma down from the recommended 2.2 level to about 1.8
 
kman said:
Yes it does and I don't know what luminance settings I've calibrated it too. Does the luminance need to be set lower on the PC monitor to stop it from underexposing too much?
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Don't make one match the other, make them both match a desired value.

If you search for cd/m^2 on TP it should bring up a couple of threads with recommended values. I think it should be somewhere between 120-140 for photo editing but if you've got a rubbish monitor like mine then the cd/m^2 becomes a compromise to achieve the desired white point.
 
I have run calibration on both monitors. One the Dell monitor I have luminance of 143ish and gamma at 2.2.

The laptop has luminance of 105 cd/m2 (about the max it will go I think) and gamma 2.3.

The laptop however is still showing more detail (can still make out lips/nose etc just barely) whilst on the monitor I can't. So, is my monitor still underexposing?
 
Dunno mate, I thought that would be the answer. The only other thing I can think of is the contrast ratio. With the spyder3 as well as doing the colour and the luminance you adjust the black and white points too to ensure you're getting detail at both ends of the contrast range. It could be that the black point on your desktop is too high. If you think of a scale from black to white, with grey in the middle you might find that the black point of the monitor is for example half way between true black and mid grey. If that were the case then all the tones between true black and the black set-point of the monitor (somewhere in the greys) will be represented as black. Not an easy one to explain without a diagram maybe but hopefully you get me.

The i1 is a pretty sophisticated bit of kit if memory serves me correctly so I'd imagine that it can measure black and white points. I think Den has one of these so maybe he'll come back and tell you if I'm talking out of my arse.

If I had your situation with my Spyder I'd try increasing the brightness of the monitor to bring out the shadow detail using the brightness control and then reduce the luminance back to a sensible level by reducing the RGB channels as required.

This calibrating lark isn't as simple as people first think which is why it makes me wonder why people bother with the travelling calibrators that they wait months to use, do it quickly, then pass it on. Chances are there is only a perceived benefit rather than a real one as calibrating colour is only half the battle (the other half being luminance and contrast ratio).
 
Laptop displays cannot be accurately calibrated.

There is no laptop in production today that has an IPS display. They're all regular cheap TFT monitors, which cannot be accurately calibrated.
 
I had a problem calibrating my works laptop but thought it was just my laptop. In that case I'd prioritise getting a decent calibration out of the desktop and not worry too much about the laptop.
 
I was just reading through some of the technical help on the i7's calibration software - lowering the gamma helps bring out details in shadow areas, brightness and contrast wouldnt help much. Its odd then that whilst the laptop gamma is more or less the same as the desktop's, I get more shadow detail from the laptop!

But i do think I should leave the gamma level at 2.2

I'd be interested to know, how much details do members here see in the picture in the first post?

Thanks for all the help and suggestions.
 
If you're looking at your laptop display from above, you'll there is much less contrast and you'll see the detail in the shadows. If you look at your laptop display from below, more things will turn black.

This is why Laptops and cheap LCD monitors can't be accurately calibrated.
 
Laptops never calibrate correctly. My Macbook's screen is terrible. Dell monitor is pretty good though, I use an EyeOne on both also but find a luminance setting of 90 on both works best for me.

These tests are pretty quick & dirty visual tests: http://www.lagom.nl/lcd-test/ . Pay attention to the black level and white level tests.

The real test is to get a print made by your lab and check how the print matches your monitor with the lab's printer profile applied in Photoshop's proofing mode. Ultimately all that really matters is that what you see (on your monitor) is what you get (from your lab). Pick something with a good range of tones, some subtle highlight detail and subtle shadow detail. There's test images out there you can download for this purpose.
 
Kaouthia said:
If you're looking at your laptop display from above, you'll there is much less contrast and you'll see the detail in the shadows. If you look at your laptop display from below, more things will turn black.

This is why Laptops and cheap LCD monitors can't be accurately calibrated.
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I understand the viewing angle issue. For my testing purposes I'm adjusting my angle of view til I get the best (most detailed) look of the image which is more or less looking straight on to the screen.
 
kman said:
For my testing purposes I'm adjusting my angle of view til I get the best (most detailed) look of the image which is more or less looking straight on to the screen.
Click to expand...

But just shifting your eyes from the top of the screen to the bottom of the screen without moving your head or the screen is going to produce differences.

Try it. Make a solid 50% grey image that fills up your screen on your laptop, hide Photoshop's menu, toolbars, etc. The top of the screen will be darker than the bottom no matter where you position your head.
 
Kaouthia said:
But just shifting your eyes from the top of the screen to the bottom of the screen without moving your head or the screen is going to produce differences.

Try it. Make a solid 50% grey image that fills up your screen on your laptop, hide Photoshop's menu, toolbars, etc. The top of the screen will be darker than the bottom no matter where you position your head.
Click to expand...

Yes thats correct there definitely is a difference. But my issue with the shadow detail is far more obvious and significant.
 
Right, because of what causes the shift in brightness and contrast proven by the little experiment. :)

If you print it, assuming your printer is also calibrated, it'll look how it does on your proper monitor. So edit your images on a proper monitor that's capable of being calibrated, and forget how it looks on your laptop, because it'll never be right. :)
 
Kaouthia said:
Right, because of what causes the shift in brightness and contrast proven by the little experiment. :)

If you print it, assuming your printer is also calibrated, it'll look how it does on your proper monitor. So edit your images on a proper monitor that's capable of being calibrated, and forget how it looks on your laptop, because it'll never be right. :)
Click to expand...

Thats what I'l do. Unfortunately I don't use my own printer to print so next time I send off for some prints I'l get an idea. :)
 
Just finally then, what do you see of the image? Does your monitor give you a decently close look to that you would get if you printed?
 
What I see on this PC is probably what you're seeing on your calibrated IPS monitor as I'm using Calibrated IPS monitors too. HP LP2475w screens. Those were calibrated with the Eye One Display 2.

When I load it on the laptop, which was calibrated (or as close as it gets) with the Spyder 2 Express, I can see some very feint detail in the face if I'm looking at my screen from above. Same results when I look on another PC using my cheap 22" Emprex widescreens (they were like £129 each from Comet about a year ago), although those were calibrated with the Eye One Display 2.

It will give you a *fairly* close representation of the colour of your image, it'll at least let you know that your white balance is generally correct, although the colours are nowhere near as vibrant or saturated on my non-IPS screens or on my laptop as they are on my HP monitors (which is how they print out on my calibrated inkjet with Ilford Galerie Smooth Pearl paper and my dye-sub printers).

Before I got the HPs, my blacks were much blacker on print than they were on screen, and a lot of the colours were much much more saturated than I thought they'd be (because I was colour correcting and processing for a screen that wasn't accurate - even though "calibrated").
 
Kaouthia said:
Before I got the HPs, my blacks were much blacker on print than they were on screen, and a lot of the colours were much much more saturated than I thought they'd be (because I was colour correcting and processing for a screen that wasn't accurate - even though "calibrated").
Click to expand...

Sounds totally normal then. I have the same setup as you (laptop screen & external screen, both calibrated), and see the same as you just described.

Moral of the story: Laptop screens do not calibrate properly so use a good screen for anything going to print.

EDIT: Sorry, I thought this was the OP I was quoting.
 
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