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Old Jan 7, 2011, 8:32 AM   #1
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Default How to calibrate

I sometimes process my pics at home and sometimes at work. At home I have a Viewsonic VX2450WM (LED) and at work I have an aging but still very good Viewsonic VX2025WM (LCD).

I calibrated both monitors using Windows' calibration tool.

For my LED monitor at home, I calibrated it further to hopefully mimic the rich color saturation of Macs I see at BestBuy.

My problem is when I post-process pics on my LED at home, they look great on both monitors. But when I post-process pics on my LCD at work, they almost always look horrible on my LED at home with over-saturated colors and lots of JPEG artifacts like banding and blocking. So I had to re-do them at home.

I guess my question is, which one did I calibrate correctly? Would an Eye-One calibration tool help? I'm not prepared to spend $150 for it, though, because my photography is just a hobby and not an investment.

To give an example, I had to redo pic #1 which I processed on my LCD at work to come up with pic #2 which I processed on my LED at home. But the thing is, if the monitor you're using is calibrated like the one I have at work, you might not see any difference.

#1) Processed using LCD monitor.


#2) Re-done using LED monitor.

Thanks a lot!

Last edited by vvcarpio; Jan 7, 2011 at 8:35 AM.
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Old Jan 9, 2011, 12:06 PM   #2
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I'm not sure what OSX your using but I know that in windows XP there is a facility for changing/adding color profiles. I'm not sure if this is available in windows 7

http://windows.microsoft.com/en-US/w...ement-settings

Also there is a free trial of DXO down-loadable, with which you could check the initial raw/jpg files for color and distortion correctness ....lens/camera modules

http://www.dxo.com/intl/photo/trial_version

Last edited by musket; Jan 9, 2011 at 12:41 PM.
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Old Jan 10, 2011, 8:03 AM   #3
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Thank you, musket. I have not seen these 2 pages before. I'm reading them now and will try afterwards.
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Old Jan 10, 2011, 8:52 AM   #4
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Do you know that you saved that image using an Adobe RGB colorspace?

Unless the applications you're using to view them are color managed, that's going to cause problems.

I'd suggest converting them to sRGB for web posting, as many users don't have color managed browsers yet. For a long time, Safari was the only color managed browser. That's slowly changing, as Firefox now supports v2 (but not v4) profiles, and IE 9 will add color management features (IE 8 and lower are not color managed).

A number of image viewers and editors are not color managed either.

So (at least for now), it's a good idea to convert images to sRGB for any type of web posting.

See these pages for more on how your browser interprets images:

http://www.color.org/version4html.xalter

http://www.gballard.net/psd/go_live_...profiles.html#
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Old Jan 10, 2011, 11:27 AM   #5
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No I did not not know I was saving in Adobe RGB. I also didn't know about Adobe RGB vs. sRGB. I just hit "save" in Photoshop and not bother with options I did not know about.

I was curious so I downloaded the images and loaded them into PS CS3. When I hit "save as", I see "ICC Profile: Adobe RGB (1998)" checked so I'm guessing that's how you knew.

Below are two images saved with different Adobe RGB checkbox settings. The one on the left (or top if they wrap around) is saved with Adobe RGB checked while the one on the right (or bottom) is saved with Adobe RGB unchecked. I can see right away a difference. I like the second one better as it does not seem to be over-saturated. I am on my work PC right now and will take a look on my home PC tonight.



I have just started looking at the links you provided but I think they opened the door for me towards understanding why my images look better on some PCs. I have always thought the culprit was either Windows' graphics-rendering engine or the browser. I have switched to SeaMonkey as my main browser because it displayed images from the Web better than IE or Chrome. Still my images look better on the Mac -- I'm guessing it's because of Safari. I still have a lot to learn. Thanks a lot for this, JimC.
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Old Jan 10, 2011, 1:36 PM   #6
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The LED version looks much better on my monitor. Less saturated, with a lot of detail on the trees and a nice white line on the water horizon.
Try to check your monitor pictures against some pro lab actual prints.
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Old Jan 10, 2011, 1:36 PM   #7
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I have the "FxIF" EXIF plug-in for my FireFox 3.6.x.x browser (which you likely have discovered is one of the few color managed browsers) and it showed the color space. Right click, select EXIF info.... there it is. Jim probably did something similar.

I see SeaMonkey uses the FireFox core. Here is a good page to test SeaMonkey's (or any browsers') color management:
http://www.color.org/version4html.xalter


Some trivia which has some influence on your results.

Your Viewsonic VX2025WM (1680x1050) uses a "P-MVA" TFT LCD panel with a CCFL back light, is likely a full 8bit and probably only covers the full sRGB color space but not much more than 76% of the AdobeRGB space. It is a good budget image viewing and editing monitor.

Your Viewsonic VX2450WM (1920x1080) uses a "TN" TFT LCD panel with a LED back light, is a pseudo 8bit as it has a 6bit panel and uses Frame Rate Control plus dithering to simulate an 8bit color depth. Like the VX2025, is also is a standard gamut monitor as it covers most of the sRGB color space and not enough of the AdobeRGB (probably about 76%) space to be considered a "wide gamut". It is more of a gaming and PS3 Blu-ray video monitor than image editing/viewing monitor.

i.e. 8bit Red + 8bit Green + 8bit Blue = 24bit RGB = 16.7 million colors

6bit = 262,000 colors
10bit = over 1 billion colors

Color Spaces > http://en.wikipedia.org/wiki/File:Colorspace.png

So you are using monitors which will not show the full extent of the AdobeRGB color space. While you're likely not missing much, some of the extreme fringes of the blues, greens and reds may not be accurate. The 3D chart of the color space clarifies the red space that the 2D CIE xy chart is not entirely accurate in depicting.

The default work space gamut for Lightroom 3 is ProPhotoRGB (even wider than AdobeRGB) and you cannot change this yet most people are using it to extract images from RAW files with monitors that only cover the sRGB space. They seem to be getting good results so the color space coverage of your monitor is not something to get worried about.

Where 8bit versus 6bit is important is where a color transitions from light to dark. 6bit monitors are more likely to show banding in this transition. A poorly calibrated 8bit monitor will also show banding.

Accurate calibration is desirable and a hardware colorimeter would be best for this, especially one that is able to also test and adjust the "white luminance" value which is how we measure the brightness of the monitor. Overly bright monitors result is perceptual errors in editing typically resulting in dark prints or dark images on a calibrated monitor. I suspect your Viewsonic VX2450WM out of the box is/was much brighter than your Viewsonic VX2025WM was when new.

In lieu of not having a calibrator, try this "eyeball" web site:
http://www.lagom.nl/lcd-test/

To get the brightness set properly by eye is much more difficult. You are trying to balance the brightness of a backlit monitor against the reflective ambient lighting of the room you are in but your eyes can't be trusted because of their perceptual bias. There also is no one "right" value - it is always a balance against the ambient light level which are different from room to room or can vary during the day if there is a window in the room. You really should edit in a room with controlled lighting but not pitch black.

Ultimately, even with use of a hardware calibrator, the one true test for monitor brightness is a test print of an edited image. Print too dark... the monitor may be too bright (printer drivers can also be an issue).

Here are example of white luminance values for a variety of lighting:

80 cd/m2 ....... Pitch dark room or close to it
120 cd/m2 ..... Moderately lit, couple of 60w bulbs in the corner of the room
160 cd/m2 ..... Workers Compensation standard office lighting.

A very rough "eyeball" test for monitor brightness is to grab a sheaf of white printer paper and hold it up next to a monitor with a white background (like Notepad maximized). If the paper is darker than the screen, your monitor is too bright in balance against the room lighting. Note that if you have incandescent bulbs for lighting the paper will likely pick up a yellow hue from the 3300K bulbs. Outdoor light that filters through the windows of your home and under which most people view prints is said to be close to 6500K (aka D65) hence this is typically the color temperature that many people calibrate their monitors to along with a gamma of 2.2.

For print matching, many of the serious editors have editing rooms/booths where the ambient lighting is 5000K (aka D50) and the screen is calibrated to 5000K.

FYI... with many of the latest LCD monitors, in order to get to the 120 cd/m2 white luminance level, people are typically leaving their monitors hardware controls for Contrast at or near the factory default but are lowering Brightness to somewhere around 15 to 25%. I don't think this will apply to the VX2025 as it is an older generation and CCFL's dim over time.

Btw... Mac Book Pro's use "TN" panels. Apple Cinema Displays use 8bit "H-IPS" panels. All current Apple/Mac's are standard sRGB; they have no wide gamut monitors at this time. The monitors you viewed at BestBuy likely have all their controls boosted, especially brightness, to attract your eye to them. They're not accurate. However, Cinema Displays, due their IPS panels, have very wide viewing angles within which the color/gamma does not drop off and this is what a lot of people note walking up to them. Their colors are vibrant even at off centre angles.

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Old Jan 10, 2011, 1:51 PM   #8
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More on browsers...

I came across a very interesting post on "Scaling and Aliasing" with photo examples as viewed in Chromium, FPV, IE9 and comments on FireFox4.

The Chrome browser was clearly superior in presenting images with certain types of content likely to generate moire.

Unfortunately Chrome is not as well color managed as Firefox or Safari.

It wasn't on this forum but if you want to see a photo example you can find it here:
http://www.malch.com/nikon/Viewing.jpg

I downloaded the originals and tested it myself with Chrome, FireFox 3.0.x.x, FireFox 3.6.x.x, and IE8 and the results mimicked what you see in that link.

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Old Jan 10, 2011, 8:18 PM   #9
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Thanks a lot for this NewsyL. Your post answered all of my questions plus more. I didn't expect to also know about my monitors' and my browsers' characteristics. I have been searching for months and haven't found answers on my color questions. I guess I've been typing the wrong search strings in search engines.

I just downloaded and installed FxIF -- it's a great tool. Looking at EXIF data is so much easier.

I configured Photoshop to prompt me to save in sRGB or Adobe RGB.

I also went to your first link, http://www.color.org/version4html.xalter, which shows if my system is "ICC Version 4" ready. Both my LCD (at work) and LED (at home) show the second image in the "Expected Results" so I guess they're not ICC Version 4 ready.

I'm referring to your post several times to study it. The lighting conditions, the calibration tool, the Mac, etc. It is quite thorough. Again, many thanks.
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Old Jan 10, 2011, 8:19 PM   #10
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Ordo, one of these days I will have a pro lab make prints of my photos. It's just a matter of time. Then I will see how different my monitor is from professional prints. Thanks for the suggestion.
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