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DigitalPro Shooter Volume 3, Issue 10, November 7, 2005
In this issue we've got a complete review if the exciting new color correction book from Dan Margulis, Photoshop LAB Color, as well as info on some great new products that have been introduced just in time for Christmas. In particular, check out http://www.nikondigital.org for the Nikon D200 specs. We've also still got a couple slots for our second Grizzly Bear & Puffin week in July 2006, so sign up soon.

The Photoshop LAB Book: The Canyon Conundrum

Could you fix the image on the left of Delicate Arch?

Can you turn 
this image
  
Into 
this image?

If you are experienced Photoshop user, I'm sure your answer is "yeah, probably, but it might take some work." The first time I worked on those images it took me a long time also. Then I read Dan Margulis' book Photoshop LAB Color and discovered how useful the LAB color space was for color correction. Sure, I'd always known that it could be used as a clever way to do Luminance sharpening and some tone correction, but never thought much about using it for color correction. Now it is one of the first tools I consider when I have an image that requires some color heavy lifting.

After reading the book (or more honestly flipping through for the tidbits I could quickly understand) I was able to re-process this image and the others shown below in only a couple of minutes each and produce results that were superior to what I'd accomplished previously with oodles of layers, masks and fiddling. What fun! A more thorough reading revealed a whole new world of color correction opportunities using the very powerful LAB colorspace.

The Magic of LAB

As someone fascinated by the way human vision works, I've always been interested in the LAB colorspace. For those not familiar with LAB, it is a representation of color that separates the luminance (overall brightness or "lightness") or "L" channel from the color channels--"A" and "B". While we most often think of the human visual system as being RGB, it also relies heavily on the contrast between Red and Green and Blue and Yellow. Not by coincidence, those are the A and B channels in LAB. The result is a very powerful colorspace that can cause dramatic changes in our perception of an image by creating and destroying contrast easily and quickly. And by having the L channel separate from colors it is possible to do operations including sharpening without accidentally adding color casts.

Upcoming Events: 3 openings remain for 2006 Grizzly Bear & Puffin week II. Week I is sold out. Stay tuned for details on our 2006 Botswana/Namibia trips (2005 is sold out). All Cardinal Photo events now feature hands-on Photoshop training using images that we shoot during the safari. We're still considering doing a one of a kind photo safari to Cambodia, Burma (Myanmar) and Thaland in 2007. If you're interested, email us at safaris@cardinalphoto.com.

Amplifying Color

This image

Quickly becomes
Whether you think of it as bringing out the color you saw in a scene, or enhancing the visual impact of an image, of of the crucial tasks in preparing many images for print is make the color "pop". Sure, you can go to far with this and we've all seen lots of gaudy photos that look like they were painted with day-glo paint but subtly ensuring that your photo catches the viewers eye is a must in many photographic disciplines.
 
The obvious tools for doing this, Hue/Saturation and Curves, for example, both have limitations. Increasing saturation can quickly lead to an artificial look and destroy detail--turning your image into vistas of unreal saturated blotches. Curves is also a difficult tool to use--in RGB at least--to really enhance color.
 
Dan shows us how many images which are a problem in RGB can be enhanced (corrected if you prefer) easily in LAB.  Because the Luminance is separated from the Magenta/Green and Yellow/Blue channels you can greatly increase color contrast using the "a" and "b" curves without destroying the detail carried by the luminance of the image. The book takes you through it all step by step, with plenty of examples and alternatives, but one key piece I took away is the technique of doing this with a curves layer that is "overkill" and then adjusting the Opacity slider to taste.
 

Tone Mapping

Short of having the ZoneMapper from LightCrafts' new LightZone product, Dan's technique for re-mapping tones using LAB is about the best I've seen using Photoshop. Because the "L" channel has only luminance you are truly remapping only the lightness tones without affecting colors. As always, Dan gives you point by point instructions on how this works, how to apply it to different kinds of images, and advice on when it might not work or might not be worth the trouble.
 
The only real downside to this approach, and also to doing your color correction in LAB, is that Photoshop doesn't allow you to mix and match editing paradigms. So you need to convert the image to LAB, do your corrections, then flatten it when you convert back to RGB for the rest of your processing and printing. I don't see any scientific or technical reason that a future version of Photoshop couldn't accommodate a mixed mode where LAB type corrections would be possible interspersed with RGB corrections. After all, the image doesn't really care what space we are looking at it through. That could be accomplished by having mixed RGB & LAB layers or by rethinking the Photoshop editing paradigm to allow commands that transcend the current colorspace. Until then though we'll need to keep flopping between spaces to use the power of these techniques.

Other Goodies

Dan's LAB book is packed with lots of other goodies including sections on using LAB to color correct skintones, fix images which require massive color changes, and quite a few good general purpose Photoshop tips. As always, there is plenty for the advanced user, including sophisticated use of channels and blending modes, while the cookbook approach makes a large portion of the book accessible to anyone willing to spend some time with the book and a couple images. I'm incredibly happy I read it as it will save me many hours in processing landscapes and portraits.

--David Cardinal, Editor, DigitalPro Shooter

New Products

First and foremost, Nikon has announced the D200, an 18-200 VR lens and a whole new macro flash setup. Read the details on our homepage: http://www.nikondigital.org

Intemos, makers of some excellent products for cleaning your digicam and sensor have produced a free downloadable sensor cleaning video.

CompactDrive is shipping a portable hard drive + card reader combo that can also serve as a AA battery re-charger. The PD70X comes with or without an installed drive. Since the Epson P4000 isn't available yet, I was about to order a Nexto CF unit for an upcoming trip, but found the PD70X and am very intrigued by the combination of features for a portable hard drive (no viewing though, so it is not directly competitive with units like the Epson). At about $150 without hard drive (www.eastgear.com) it isn't too much more than a reader + drive case + battery charger and it is more versatile and more compact. For those who can wait, I'll post a more complete review after I've used the unit for a few weeks.

Wimberly has delayed the Wimberly II head until December but is offering loaners to customers on the wait list who have critical shoots in the meantime.

Maha has a new portable world charger for AA Batteries (MH-C204W) which is quite quick. One warning is that (like the D1X after the firmware upgrade) it is much pickier about which batteries it will recharge. If your batteries are at all worn out or have any internal defect it may report them as bad rather than recharging them. You can purchase it from Thomas Distributing.
  Dan Margulis, color correction guru and author of some of the best books on Photoshop color correction, has written a new book on using the LAB colorspace for color correction. My copy is on the way and I'll be doing a more complete review, but it is such a unique idea and has received so much good feedback that I wanted to give you a heads up. You can buy the book online.

DigitalPro Tip

All you need to do to assign a keyword or category to an image in DigitalPro is check the box next to the category or keyword. Or you can drag images to the category or keyword.

--David Cardinal, Editor, DigitalPro Shooter
 

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