QTR-Quadtone RIP

I've been working on a curve for my Premier Art FineArt paper, using Paul Roark's curve as a starting point. His curve was fine, but I wanted to learn more on how to do these curves, and I was ok till the linearization table step. That step calls for entry of Lab L figures.
Since I use use Photoshop Elements, Lab L in the mode tab was not available to me. So I went to the Elements Village website and asked for help there. I came up with two excellent suggestions:

1> One suggestion was to install SmartCurve, which ends up in the Filter tab:
http://www.softpedia.com/dyn-postdownload.php?p=108966&t=4&i=1
2> the other suggestion is to use this converter: http://www.easyrgb.com/index.php?X=CALC#Result

This intro is rather sketchy, please take a look and if you need any details, please submit!

Regards,

Paul

This might help how to use these:
In both cases, you're working with PS Info Palette and you hover the mouse over the grey patch.

In #1, click on "Color Space" and select "L*a*b" then in the "Channel" box select "Lightness". Then "L" should appear at the upper right.

In #2, insert the three RGB numbers (all will be the same because we're dealing with grey), click on "start" and in the next screen you'll see several results, among them L*ab. Ignore illuminant and observer.