Sunday, February 10, 2008

LAB Compared

I have finished watching the two series of LAB videos on kelbytraining.com and I tried an interesting experiment. At the end of the series are some images from others he applies his techniques to. After seeing his work on the first one I decided to try working on the image on my own (they supply many of the images). I stayed in RGB, did an Image/Adjustments/Auto Colour to the image, then used Akvis Enhancer and voila, I had a better result in two steps than Margolis had in 20 or so. Might be luck, so I did the same thing with the second image after only watching the beginning of his process. This time I had to do a bit of saturation adjustment in addition to the above three steps, but still, we're looking at 3 vs. 20 steps. For the last image I did my adjustments before watching the video and the results were very similar - 3 steps for me, 20 for him.

So, does this mean that L.A.B. is a crock? Hardly, but it's like I say to my patients, if you see a gall bladder surgeon with abdominal pain - there's a good chance he's going to recommend surgery - it's the only tool he has, and he's either going to make that tool work, or admit he can't help you. To a hammer, everything looks like a nail, even a screw. Well, seems to me that by embracing L.A.B. you run the risk of being the carpenter who only has a hammer. Great tool but sometimes a screwdriver is what's really called for.

I think this means that we need to learn where L.A.B. excels, where it can do things not possible other ways and Margulis certainly shows that - his blurring of a and b to reduce noise was nothing short of miraculous. Some of the manipulations which only apply to the problem areas of an image without messing with the rest of it through 'blend if' and 'apply image' are very impressive. His showing me how to down play the damage to light tones in my sharpening routine is really important to me. Other techniques, well just maybe a screwdriver is sometimes the better tool.

5 comments:

G Dan Mitchell said...

I think you may be right about two things here.

First, there are multiple ways to skin the cat, and I _think_ you can accomplish much of what the folks using L.A.B. through alternate techniques. If there are a few situations where that isn't true than it could make sense to learn this approach as another alternative.

I also agree with your observation that the way that you are familiar with may be the best for you, but not the best for others. Folks with a lot of "chops" using L.A.B. have developed instincts that probably make this an effective way for them to work - but for those who don't share that background (or bias?) this may not be the answer.

Dan

My Camera World said...

It is important to remember how LAB works and therefore were to use it to best make use of these features.

There are only 2 colour channels (Red1Green and Blue Yellow)

Lab allows you to increase the colour separation between these colours as you increase the steepness of the curves. For low saturated images where there is a mix of these muted tones combinations, LAB will make them pop and increase the colour separation and in effect the colour contrast between these tones.

LAB also does a wonderful job, with one curve to correct the blue haze found in many landscape scene with distant views. Only if you wanted to remove it.

Since LAB effect different colours than RGB it is way easier to enhance yellow by itself.

It is also a good source to get different masks than those found in RGB.

Some times I even go into CMYK (new image, not conversion as you may loose saturation) to also get masks. (my latest blog looks at Masks)

There are no perfect tools that do everything. Some are better in certain areas. I do think it is good to experiment as this sometimes leads to better workflow process.


Niels Henriksen

Alan Rew said...

George,

You say
"his blurring of a and b to reduce noise was nothing short of miraculous"

I haven't seen the Dan Margolis video, but this probably isn't 'his' technique. My copy of 'Real World Adobe Photoshop 6' by Blatner and Fraser, published in 2001, includes this technique (chapter 9, page 379).

I remember the bad old days of film scanning, and using the dust & scratches filter on the a & b channels in Lab mode.

Alan

George Barr said...

Dan warns that there are significant changes to his methods in the video as he has learned better ways of using LAB since writing the book.

George

Anonymous said...

Having studied heavily margulis lab on several of his books i have to say that the techniques he presents are for seriously out of tune photos. A good photographer can do with far less complicated interventions.

Second i do not think that you generally you have so few passages in your light room :-D