Curvemeister Forum

After some hesitation, I choose a small area of foam on the left hand side as the neutral. I also moved both ends of the lightness curve to increase the contrast rather than setting specific highlights and shadows.

Richard

Richard,
The neutral in this image is kind of a make or break item...you are close but the green water gives this one away. 

By the way...I noticed that you are doing a "Man From Mars" saturation boost in LAB.  You certainly can use that method if you prefer but....

One of the reasons the Dan Margolis uses that method is for control of color cast in Photoshop.  If he moves the A and B channels separately he has to move them the same amount to keep the color balanced.  In CM we can use the saturation slider.  This keeps the a and B channels "locked" together and allows you to increase saturation without introducing color cast. 

You will find little of no difference between the saturation slider and the "Man From Mars" because most of the color information is very near the center of the A or B channel.  Therefore, in order to get the results you want with Man From Mars you have to force the curve to "snap" over to the frame edge.  This causes the bulk of the curve to fall into the same area as it would if you rotate the curve ends using saturation slider. 

In fact in CM it is 1 adjustment slider; where you would really have to do 2 or 4 adjustments in PS to get the same result depending on how you want to set the curves.

Greg

The "Man from Mars" was not intentional, but I have the impression that it ocurred when I started to move the neutral point around after having already modified the a and the b channels. As a general rule, should I always use the saturation slider after having set the neutral rather than modifying the a and b channels separately? Aren't there times when one channel should have a stronger modification than another or will this always lead to

Continuation of my post:

lead to a color cast? I have recently received the Margulis on LAB color but it looks quite challenging.

Thanks,

Richard

When you set a neutral you are telling LAB what the "new" center of the grid is. 
If you set a neutral and then saturate the neutral you have set will stay neutral...

Dan's LAB book is very informative...He has gone beyond the information in the book and some of the "beyond" is incorporated in the class...
Some of the info in the book is actually out of date so test it out before you take it as the gospel...

Greg

Are there certain parts of the LAB book that you would particularly recommend that I read or that I should avoid.

Thanks,

Richard

I would say some of the sharpening stuff is out of fashion now...But overall the book is a great learning on the LAB space.  Chapter 13 takes a lot of understanding and patience...as well as the chapter on Blending..

Chapters 1-4 are really very good for this class.  We depart from a lot of the stuff Dan teaches because we have better tools than he does...
The whole of Chapter 12 can be done faster and easier I think; in CM but time will tell...
Actual Mileage May Vary...some taxes and fees apply...

I think I better go re-read the book because I see a lot of topics I want to have fresher in my mind...

Greg

Dan also has some instructional videos on the use of LAB at kelbytraining.com. I have just started to watch the beginner's video and will continue the videos along with the book as time permits.

Richard

Just realize that Dan jumps through some Photoshop hoops that you do not face with CM.  Many times he will convert an image to a color space, make an adjustment and then convert back...Most of that stuff falls away with CM...

Greg