The Digital Photo Guy

Monitor Calibration

by on Dec.28, 2013, under Articles, gear, Lightroom, Monday Morning Tips, Photo Editing

A Boring but Necessary Chore

I recently replaced my 6 year old colorimeter with a new Datacolor Spyder4Pro from B&H Photo Video and was amazed at how much the technology has improved. I lucked out and stumbled across it during a sale and got it for US$125 versus the regular price of US$169 but I can honestly say it it’s worth every penny of US$169. Currently, B&H is offering a memory card worth $30 if you buy the Spyder4Pro.

This was prompted by problems I was having printing a photo for a friend. It’s a sunrise filled with subtle yellows and reds and, no matter what I tried, the colors just weren’t printing correctly so I wanted to be sure my 4 year old monitor and 6 year old colorimeter were correctly displaying the image. Also, a new colorimeter was cheaper than a new monitor. Monitors and colorimeters are prone to drift as they age. Like people, an old colorimeter or monitor doesn’t work as well as internal parts begin to age and degrade. Lastly, software is a key component of colorimeters like the Spyder4Pro. As you might imagine, vast software improvements have occurred since my last consumer colorimeter was introduced 7 years ago.

The following screen grabs show some of the features in this low-end colorimeter. The first image is the opening splash page that shows the different info and test modes. The first time you’ll need to do a Full Calibration (FullCAL) where the software requests basic info about the monitor and checks the monitor’s capabilities. After that, it’s only necessary to do a Recalibration (ReCAL) as all the basic info is already in the software.

spyder4Pro_screen1   spyder4pro_screen2   spyder4pro_screen4

spyder4pro_screen5   spyder4pro_screen6

The next three images show one of my favorite features, selectable test images that can be enlarged for closer inspection. Clicking on the 4×4 matrix enlarges a 2×2 segment. Clicking again on one of the four images displays a single image at full size. For my purposes, I tend to check the Gretag-Macbeth Color Checker because I have one and can compare the screen directly against the “real deal.” I also like the four people images in the upper right corner because skin tone is universally understood.

The final image shows a graphical representation of gamut. My LG E2250T, a relatively inexpensive TN (twisted nematic) LCD monitor can display about 90% of all sRGB colors and 69% of Adobe RGB 1998. This type of chart helps me visualize what I can or can’t see on my LG. When I bought the LG about 4 years ago, TN was the most cost effective technology but IPS (in-plane switching) produced the widest gamut and best color representation. Unfortunately, IPS monitors were very expensive at that time. Today, good IPS monitors can be had for less than $500 with some in the sub-$200 range. My next purchase will be a good IPS monitor but, for the moment, the LG is still working well enough and the Spyder4Pro confirmed that for me.

The biggest problem with the Spyder4Pro is the lack of a manual so, if you buy one and run into difficulties, either view one of the videos on YouTube or, if you’re desperate, e-mail me and I’ll try to help.

Gamut, Color Space, Monitors and Oh My!

I’ve been spending a lot of time researching, reading, studying and trying to understand how colors captured by a digital camera sensor are handled inside Lightroom and, most importantly, how is color displayed on different output devices ranging from monitors to televisions to projectors to prints. Normally, I’m the sort who likes to tackle the whole gamut (pun intended) of issues at once because what I learn in one area can often trigger an idea or understanding about another aspect. Unfortunately, this hasn’t been practical for these subjects because 1) this has turned out to be a HUGE area of study and 2) my brain can’t keep up with complex, technical details anymore. I hate to admit it but I can no longer keep multiple (6 to 10) complex thoughts or details in my mind and retrieve them on cue. If it gets much worse, I’ll probably have to report to the Soylent factory! (If you’re too young to know about Soylent Green, Google it. You may be surprised how much us old fogies knew about the future.)

Anyway, I’m writing a future article about color space in Lightroom. I’m sure anyone who reads this blog is aware of sRGB, Adobe RGB 1998 and ProPhoto RGB. Well, allow me to throw out a few tidbits that I’ve learned in my research. Lightroom histograms use Melissa RGB, a ProPhoto variant named for Melissa Gaul, one of the original Adobe LR team members. This is the same team that included George Jardine, the LR instructor from whom I’ve learned more than any other instructor, period. Melissa RGB assigns a gamma of 1.0 instead of the usual 2.2 because 1.0 is the native gamma for most digital cameras. However, the LR Develop module uses ProPhoto RGB with gamma 2.2.

Why the difference? We have to understand the purpose of each. Histograms are literal representations of the pixels in an image. Therefore, mucking (a technical term) with gamma can change the actual histogram. However, in the Develop module, we’re trying to adjust the photo for human consumption.

Human eyes see things differently than a camera sensor. If a camera captures a scene that is twice as bright, it duly records twice as much light. A human eye, on the other hand, automatically compensates by toning down the bright scene to preserve shadow details. In order to produce an image that mimics what a person sees, a gamma curve is applied to tone down bright areas and bump up dark areas. Ergo, Melissa RGB produces an exact representation of what the camera captured but ProPhoto RGB produces what the human eye would have seen.

Sorry I don’t have “purdy pitchurs” to illustrate my points. I hope to have some by the time I finish the article. Also, sorry if this is too techie, geeky for you but I’m only writing about what interests me anymore. Have a great 2014.



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