Calibrating a laptop...

[IzzieK]

My desktop's two monitors are both calibrated. Now I have a laptop I use for traveling and also for my make-shift studio across the other room to my den. When I calibrate my monitors (desktop) it asks me if I want to continuously check the ambient light in my room. So my calibrator is continuously connected to my desktop actually.

Now I want to calibrate my laptop too. Do I need to buy another calibrator for it or can I use the one I use for my desktop even though it may not continuously check for ambient light in any room I will have my laptop in, eg., an airport lounge or my kitchen should I decide to bring it downstairs there? What is the best way to calibrate a laptop?

At the moment, what I do is have a portable drive to store my images from my laptop activities and just bring that to my desktop. If I am not at home, this is quite difficult if I have to wait before I go back home to check if my images' colours are good enough. I want to be able to use my laptop to edit images too if I can.

Thanks for any reply I might get...

[Shadowman]

I have one connected to my laptop and I set it to calibrate every three weeks, I know it's supposed to be done more often, but it continually checks ambient lighting and automatically adjusts the brightness. If cost isn't a concern then I would get a separate one for the laptop.

[Colin Southern]

Usually the only calibration adjustment on laptop screens is brightness, so it's actually the profiling that does most of the work. But to answer the question, just use your existing colorimeter and then disconnect it -- the ambient light measurement is for the most part more "gimmick" than anything useful.

[Colin Southern]

I have one connected to my laptop and I set it to calibrate every three weeks, I know it's supposed to be done more often, but it continually checks ambient lighting and automatically adjusts the brightness. If cost isn't a concern then I would get a separate one for the laptop.

3 weeks was a good default for CRT based monitors, but for LCD monitors once or twice a year is fine so long as nobody plays with any of the settings.

[Manfred M]

Isabel - just to add to Colin's comments about the ambient setting; I did a test on my equipment and developed profiles with different ambient light settings. I do all my work in my basement office that has no windows, so I can control my ambient light quite nicely.

I did the ambient light reading and developed profiles is total darkness, just a very low light and normal illumination. Frankly, I could not see any difference in the the profiles, when I used them in different lighting conditions, although quite frankly, the images on the screen looked a lot brighter when I looked at it in a darkened or semi-darkened room, that was the only real difference,

The normally lit room actually ended up working out best for me as the on-screen images and printed images look about the same.

I also found the same thing with the re-profiling. With a CRT screen, I would notice a difference after a month (and even more frequently when it stared to die). I notice no difference between profiles that I do once a year (and I do that just in case something has changed).

[Mike Buckley]

Thanks for the tips, guys. My calibrator's default setting reminds me to recalibrate every two weeks, possibly because it is ignoring that I'm using an LCD screen, but more probably because the developer wants me to erroneously think that I'm getting so much value from its product. I'll change that setting.

[Shadowman]

3 weeks was a good default for CRT based monitors, but for LCD monitors once or twice a year is fine so long as nobody plays with any of the settings.

Colin,

That's good to know.

Thanks

[IzzieK]

Thanks for the tips, guys. Especially Colin thanks for telling me I can disconnect my calibrator to the laptop. My calibrator reminds me to recalibrate every two weeks too, Mike so I do not disconnect it. And thanks Manfred and John too. Now I understand using the profiling better.

[Mike Buckley]

My calibrating software will now be reminding me every six months to calibrate, no longer every two weeks. That's the longest period of time that can be configured in the reminder system.

[IzzieK]

When my calibrator comes up in a few days I will see what options I have. Thank you all for your responses. I have learned from all your responses.

[Colin Southern]

BEGIN_RANT

In 99% of cases people aren't CALIBRATING their monitors - they're PROFILING them. Calibration is the adjustment of controls (eg brightness and contrast etc) - and most colorimeter manufactures simply say "reset you monitor to factory defaults" to accomplish this phase (because it's easy to make things worse by adjusting them, and they're supposedly set close to what's needed by default anyway). Profiling is a software adjustment where "the colour requested" is translated to "the colour required".

Most of the time when people say "calibrating" they're meaning "profiling".

/END_RANT

[Mike Buckley]

BEGIN_RANT

You should rant to the manufacturers, Colin, not to its users who don't have technical degrees or training. When I use a product that the manufacturer explicitly identifies as a calibrator and that the manufacturer explicitly says is used to calibrate my equipment, and when I do so in exact accordance with that manufacturer's instructions, I don't mean that I'm only profiling my equipment; I mean that I'm also calibrating it.

Based on all of that, I have every bit as much reason to call the equipment that I hang in front of my monitor a calibrator as I have to call the equipment that I use to take pictures a camera. If it's not sufficient that Nikon calls the latter equipment a camera, so be it.

/END_RANT

[ajohnw]

The only thing that might be of concern according to some is if an older calibrator is used on a LED screen. I did though and when I bought another calibrator that was for LED or conventional back lit displays there wasn't any difference that I could detect.

I have messed with brightness and profiling and have noticed on a LED monitor that it makes very little difference to the profile that is generated.

On the rant. Calibration is the act of getting as many of brightness,gamma and colour temperature as close as possible to what is wanted. In cases I am aware off software would just measure these quickly checking gamma at a few points.

Profiling is generating corrections to make all of these as accurate as possible. This generates a profile that software and in some types the video card also uses to correct the colours. There are several types of profile. I use an XYZ LUT plus swapped Matrix profile. (Look Up Table) Not sure about the wisdom of this but it usually gives the most accurate profile.

When finished one has a calibrated display in most quarters. Confusing really as in most cases calibration doesn't mean measuring how far something is out rather quickly and roughly. It usually means correcting what ever it is within defined limits.

John
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[Colin Southern]

BEGIN_RANT

You should rant to the manufacturers, Colin, not to its users who don't have technical degrees or training. When I use a product that the manufacturer explicitly identifies as a calibrator and that the manufacturer explicitly says is used to calibrate my equipment, and when I do so in exact accordance with that manufacturer's instructions, I don't mean that I'm only profiling my equipment; I mean that I'm also calibrating it.

Based on all of that, I have every bit as much reason to call the equipment that I hang in front of my monitor a calibrator as I have to call the equipment that I use to take pictures a camera. If it's not sufficient that Nikon calls the latter equipment a camera, so be it.

/END_RANT

Possibly the manufacturers have got as big a headache as I have trying to get people to use the correct terminology that they've just given up (which in my opinion sets a dangerous precedent) (much like "HDR photos from a single exposure").

I don't have a technical degree either (I left school at age 15), but I still know it's called a colorimeter; a "calibrator" is a very generic (and inappropriate) term IMO.

[Mike Buckley]

it's called a colorimeter

If you really wanna have a legitimate reason to rant, I never heard of that term until I saw you using it regularly. (You should charge me extra for that.) You will be glad to know that Datacolor calls their Spyder4 product a colorimeter, but only if you drill down into their specifications and press releases. Otherwise, they call it a calibrator.

[Colin Southern]

If you really wanna have a legitimate reason to rant, I never heard of that term until I saw you using it regularly. (You should charge me extra for that.) You will be glad to know that Datacolor calls their Spyder4 product a colorimeter, but only if you drill down into their specifications and press releases. Otherwise, they call it a calibrator.

Yep - they've given up. Beaten into submission by the masses.

Think I'll join them and just opt out of these "calibration" discussions.

[ajohnw]

It's best to just laugh Colin. Going on the software that came with my colorimeter it wont actually calibrate which caused me some confusion when I used software with it that would. It took about 1 min and I wondered what the hell use is that. A profile and report takes 45min.

I thought I would have a look around at them recently and searching colorimeter bought up some in Computer/etc but monitor calibration bought up more. Also tried photospectrometer looking for a specific type. The name confusion probably doesn't help sales either. In the end I concluded that I would see if I could hire a spectrometer type and generate a correction profile for my own cheap one or buy a more accurate colorimeter. Eventually decided to just concentrate on my PP.

A much more interesting aspect is how I become dissatisfied with previous PP when I change monitor for a "better" one. Is it down to the monitor or my PP? I'm tempted to recalibrate taking ambient light levels into account. Or should I PP in a manner that reduces dynamic range so all are more likely to see it as I see it.

John
-

[Mike Buckley]

I have always admired dpbestflow.com for their explanation of best practices. Their explanation of calibration and profiling shown below seems to be the same as yours.

===================


Calibration

Calibration is the process of setting the monitor to the desired neutral output. It includes settings for luminance, white point and gamma. Once it's been neutralized as well as the monitor's controls allow, it's time to measure the color and help to perfect it with software.

Profiling

Profiling is the process of measuring the imperfections in the monitor, and creating a "filter" that compensates for those imperfections. Using the parameters set in the calibration step, profiling requires using a hardware device, often referred to as a "puck" (a Colorimeter or Spectrophotometer), that hangs over the monitor screen and reads several sets of red, green, blue and grey patches generated by the profiling software. The color patches are measured by the puck as they are displayed. The differences between the colors the monitor displays in its native state and the true colors of the patches are used to create a monitor profile which will cause the monitor to display the true colors more closely than it did in its native state.

[Colin Southern]

I have always admired dpbestflow.com for their explanation of best practices. Their explanation of calibration and profiling shown below seems to be the same as yours.

===================


Calibration

Calibration is the process of setting the monitor to the desired neutral output. It includes settings for luminance, white point and gamma. Once it's been neutralized as well as the monitor's controls allow, it's time to measure the color and help to perfect it with software.

Profiling

Profiling is the process of measuring the imperfections in the monitor, and creating a "filter" that compensates for those imperfections. Using the parameters set in the calibration step, profiling requires using a hardware device, often referred to as a "puck" (a Colorimeter or Spectrophotometer), that hangs over the monitor screen and reads several sets of red, green, blue and grey patches generated by the profiling software. The color patches are measured by the puck as they are displayed. The differences between the colors the monitor displays in its native state and the true colors of the patches are used to create a monitor profile which will cause the monitor to display the true colors more closely than it did in its native state.

And we're surprised because? ...

[Mike Buckley]

And we're surprised because? ...

Once again, you seem to be the only person who is surprised.