Calibrating a dual monitor setup?

[bluphoto]

<p>By "System" I'm talking about monitor AND printer.<br>

If I "calibrate" my monitor, and create an image in photoshop on my computer, then print it on my "calibrated" printer, then can I be sure that an image that I get back from a lab, for example, will have the same tones as the one I printed myself?<br>

As do many if not most graphics professionals (though I'm not one), I have dual monitors using an extended desktop. How do I calibrate both screens to have neutral greys, for example? One thing I HATE is having pinky, bluish or orangy scrollbars / toolbars in various applications such as word or excel. I want neutral greys in photoshop and neutral greys on my Photoshop and office toolbars etc. Right now, when I move an image from primary to secondary monitor etc, my greys change colour considerably.<br>

If my friend calibrates their monitor and printer, then is the idea of calibration that I can rest easy that my images will look and print the same on his system as it did on mine (eg, being able to "just" see tonal separation between model on background in a low key shot)?<br>

I guess most of these are no brainer questions to many of you, though I'm just a little perplexed.<br>

PS. My system is Win7Ultimate/CS4/Landscape Dell Ultrasharp 24"/ Portrait Dell 22" (not sure model) & Epson R2880, if that makes a difference?<br>

Many thanks<br>

Guy</p>

[patricklavoie]

<p>1_theres not really such thing as a calibrated printer, but you have to use the appropriate icc profile for your printer / ink / paper combo.</p>

<p>2_having a calibrated monitor dont garentee anything, i mean you can have a monitor calibrated or not and still print correctly..</p>

<p>3_no having a good print at home doestn mean you will also get a good print with another lab.. too many factor can go wrong, and this is why not all lab are created equal. Depend on how they are well maintain and professional.</p>

<p>4_To calibrate 2 monitor you normally need 2 video card so each monitor ahve her own calibration, and you need a device like a spider3 pro or eye one display 2 to make that work.</p>

<p> </p>

[Tim_Lookingbill]

<p>Just to add to Patrick's number (4)-the reason for the two tinted grays between the two monitors is that Window's can only load one "Calibration Curve"=LUT that works out all the color cast variances throughout the entire 255 gray levels by tweaking each RGB curve.</p>

<p>Two video cards will fix this because each will have their own unique RGB correction "Calibration" curves.</p>

<p>Macs can do this with just one video card.</p>

[William Kahn]

<p>I don't know why the myth persists that you need two video cards for a dual monitor display on a PC. There are PCI cards that handle dual monitor setup with individual calibration profiles very well (such as the ATI Radeon HD 3400 series), assuming you are using calibration software and colorimeter like Spyder, etc.</p>

<p>The difference in grays between the two monitors probably has more to do with the monitors not being identical than with any calibration problems.</p>

<p>In any case, you really only need to calibrate one monitor, that being the one where you do your image editing.. Do some experimenting. Calibrate both monitors, print a test image and see which monitor comes closest to matching the print for color, brightness, contrast, etc. Use that monitor for editing images, and the other for your Photoshop (or whatever) screen and palettes. Something like this:</p>

[patricklavoie]

<p>William, the myth is because not all PC have the dual support video card.. so you cant call that a myth ; )</p>

[William Kahn]

<p>Well, I meant like this:</p><div></div>

[William Kahn]

<p>Patrick, it's true that not all PCs come with dual monitor cards (not everyone needs two monitors). But the myth seems to be something like, "You can't do it on a PC - get a Mac", which is certainly not true.</p>

[patricklavoie]

<p>William, i think you put word on Tim mouth.. all he or at least I said was that on PC you *normally* need a 2 video card setup to drive 2 monitor with there own calibration. Some PC come with a dual video card system that let you do this form start.</p>

<p>I was not aware that it was not a *problem* on a Mac, as Tim said and simply state. I personnaly have a NEC 2690wuxi connect to a Imac so both have there own calibration anyway ; )</p>

<p>Mac are not better or worst vs a PC.. so lets not go there ; )</p>

[William Kahn]

<p>OK, Patrick, let's leave it at that... :-)</p>

[martin_howard1]

<p>Dual screen calibration is only a problem on a Windows PC when using a AGP based video card.<br>

A Dual head PCI-E card will be 'seen' by windows as 2 separate cards.<br>

Most calibration software makes the process painless for the user - i.e. the Spyder3 sofware identifies which monitor you wish to calibrate and proceeds from there. The end user need not worry about look up tables etc!<br>

With regards to print matching, the best way to ensure a close match to lab prints is to get hold of their printer profile and use this to soft proof your images on screen in photoshop.</p>

[bluphoto]

<p>My card is PCI-E I think, though I'm using one monitor on the DVI port and another on the VGA port. Not sure that this constitutes dual head. It only has one of each.</p>

[joseph_smith3]

<p>To add to the discussion, if you have profiled both of your monitors, you might be able to select one of the profiles to be active in your windows operating system. I know you can do this in Windows 7 as I have done it when I switch between the profile for my digital projector and the other profile for the laptop. If I had a dual monitor setup for digital photography, I would probably just profile the monitor where my images appear and not profile the other monitor.<br>

Joe Smith</p>

 

[Tim_Lookingbill]

<p>Well I thank William for filling me in on what you have to do to get dual LUTs to work on a PC system. Not many know all the gotcha's on Windows systems when it comes to digital imaging workflows and really why should they. Macs have gotcha's as well but not in the graphics card department.</p>

<p>But I'ld like to be thorough on this subject of how exact you can get two displays to look on any graphics system by submitting the link below that comments on the inaccuracies that are inherent with colorimeters in general:</p>

<p>

<p >http://lists.apple.com/archives/colorsync-users/2005/Feb/msg00062.html </p>

</p>

<p > </p>

<p >And this is a copy of what I posted at Luminous Landscape recounting my experience I'm having on my iMac and a Dell 2209WA:</p>

<p > </p>

<p > </p>

<blockquote>

<p >Waited to see if anyone provided a solution just in case what I'm about to say might be wrong.<br /><br />I'm getting subtle color differences between a 2004 G5 iMac connected to an external 2009 Dell 2209WA both calibrated with the original i1Display (not 2) using i1Match 3.6.2 and both having an "sRGB-ish" color gamut. <br /><br />I've been investigating this for several weeks and I've come to the conclusion that RGB colormeter pucks aren't the most consistent when it comes to getting exact color matches between two displays.<br /><br /><br />This Colorsync Mailing List discussion pretty much confirms this:<br /><br /><a href="http://lists.apple.com/archives/colorsync-users/2005/Feb/msg00062.html" target="_blank">http://lists.apple.com/archives/colorsync-...b/msg00062.html</a><br /><br />The black point on the iMac is far more dense and rich looking compared to the Dell's. However there's no correction in the final i1Match LUT calibration RGB curve correction graph to show a compensation in the shadow roll off to correct for this mismatch even though both have identical Black Density and overall Luminance targets, color temp and gamma readouts. PDI color target skintones will have a bit more yellow on the Dell compared to the iMac but the image still looks great overall.<br /><br />Also I've found that color temp white point color cast appearance with regards to perceived amounts of blue/yellow calibrating between 6000K-(iMac native) to 6500K can vary but not be noticeable to the eye until conducting long edits on the iMac and switching back to view the image on the Dell where I suddenly notice a slight dull yellowish warm cast due to the eye's adaptive nature. I have to crank up the blue channel on the Dell's WP to get rid of this dull yellowish tinge but now my white point clearly doesn't match my iMac's but the skintones match. <br /><br />I kept bangin' away adjusting the Dell's color temp and contrast appearance through its OSD menu to get it to visually match as exact as possible to the iMac and then recalibrate, but I still was always slightly off either on the green or red side afterward so I just gave up and accepted this slight and subtle mismatch.</p>

<p > </p>

</blockquote>

<p >What it bowls down to is how subtle a difference are you willing to put up with in getting two displays to match exactly. It's the degree of subtlety that's never quite communicated in discussions of this sort.</p>

[Tim_Lookingbill]

<p>Below is a shot of how close a match I can get my iMac and Dell 2209WA showing the subtle differences not only in neutrality but the amount of yellow in skintone. It's hard to determine if it's the display profile's LUT=(RGB Calibration Correction Curve) or its embedded mathematical matrix colorant describer numbers color managed apps use to control hue/saturation. Maybe it's a combination of both.</p>

<p>One things for certain in my experience with this is I can get my Dell to better match my iMac using Apple's eyeball calibrator over letting the colorimeter do it, but it takes some work.</p><div></div>

[martyx]

<p>This is an interesting topic which has occurred on many photo sites. Up front I must disclose that I am no expert on this and also that I have a small commercial interest in some calibration software for which I wrote the user manual.<br>

Back to the topic.<br>

When running 2 or more monitors from a single PC you will require either a video card for each output / monitor or a multi channel output video card, typically a dual channel card. Under Windows XP at least and likely the graphics software running the card(s), you will need to set-up the monitors to display individual channels. Your post suggests you have done that.<br>

Calibrating monitors is then either done by visual assessment alone using the monitor controls, software calibration apps, or hardware software devices such as Spyder Monkey and others.<br>

In each case, the ambient light used and the surroundings will have an effect on the perceived colouring of images on screen and printed. The ideal situation is to use a room capable of being totally darkened and then illuminated with a known and consistent value light source, such as daylight temperature energy saver lamps(s). Keep in mind that bright colours in your field of view when viewing monitors can influence how you perceive colours, so a clear bench and workspace is beneficial.<br>

Calibration starts with adjusting each monitor using the brightness and contrast controls. This stage is or can be tricky as it is always dependent upon the software driving them so start off with your graphic cards at 50% brightness and contrast. Another thing to keep in mind is that for LCD screens, brightness and contrast are different to CRTs. as LCDs rely upon a backlight to illuminate the display whereas CRTs use glowing phosphors so the traditional concept of contrast especially is used in a different context.<br>

Both software and hardware/software calibrations make adjustments to the LUT or Look Up Table, which determines how much value to send to the monitor for each of the 255 steps between black and white.<br>

So, having your monitor(s) displaying a reasonable gray scale, plenty of which may be downloaded for free you then make fine tuning to each of the gray scale steps along the brightness gradient. Other factors to consider are gamma and colour temperature.<br>

Having a neutralised colour work space and using colour consistent illumination will rule out any ambient colour temperature errors and thus any deviations to such will be down to the LCD backlight.<br>

Gamma is an overall adjustment, either raising or lowering the black level or setting the baseline higher or lower.<br>

When using Lutcurve by Atrise for example it is possible to create a clean gray scale for each monitor which is visually compatible, one with the other yet each LUT retains unique values.<br>

Once a satisfactory calibration has been achieved, sometimes requiring a few sessions of fine tuning, it is then reasonable to expect to see a clean gray scale which is reproducable on other calibrated monitors and appear as clean.<br>

Comparing screen displays to print output is apples to oranges, both are fruits but very different.<br>

Monitors deliver image by direct light whereas prints use reflected light, as you are already likely aware. Anyway, your prints are expected to be better when using calibrated monitors as you make adjustments within image editing software, Photoshop for example, based upon what you perceive not what some peice of hardware hanging off your screen dictates. Calibrating printers is less irksome but in the real world relies upon how satisfied you are or clients or labs with the printed output. <br>

A well calibrated monitor will at least allow for less guesswork when editing and enable for printer corrections based upon a known good value, that is a clean gray scale.<br>

Trusting this helps and if it's telling you what you already know fine and if it's incorrect I wlecome comments.</p>