AdobeRGB like sRGB uses 8, 16, or 32 bits for each color Red, Green and Blue.
Although Adobe RGB is expanded to such that those same millions of colors cover a wider area of the color chart. That simply leaves bigger holes between colors.

Lab on the other hand defines pretty much any color you could imagine and those not possible... How do you envision or print a very bright dark-green in RGB?
Lab uses real numbers (e.g. 1.5, 2.73, etc...) AdobeRGB and sRGB use integers. So although Lab uses values of only 0-100, the possible color values are almost limitless.
A bright green (green value of 100, actually a:100, b:100 I believe) could also have a luminosity of L:1, and therefore still be very dark.

Some things work better in Lab. But some things just make more sense and work better in the RGB modes.
A great book to check out is "The Canyon Conundrum" by by Dan Margulis.

Tripod, bulb mode, and remote cable release. Focus on distant nearby object or infinity leave auto focus off. I would not use noise reduction mode, as you'll miss a lot of shots waiting for the dark frame to be calculated.

I generally use f/8, ISO 100 and about 1 to 2 seconds for shutter speed. Really depends what you like for the effect.

Try to follow the trails up and anticipate where the fireball will explode.
Sometimes open the shutter to get the trail and initial explosion. Other times I like to leave a hole in the middle so I don't open the shutter until after the initial explosion.

For roman candles or other repetitive pattern making sets I'll leave the shutter open as much 5 to 10 seconds to capture a bunch of stuff . So really very little on rules.

[edit] wow, too slow on my reply. Was trying to look up some of my examples but the website stripped all the exif info.

Anyway, another good point Tyr brings up with the "machine gun mode" -- lots of memory cards. I shot rather casually the last time I was out and had over 500 photos taken.
I would add, RAW mode helps a lot for handling of noise and finer details in the fireworks where there may be a large range of brightness to be captured.

You cannot turn off the camera built-in flash's pre-flash. This is why dumb remote flashes don't work well.. they often flash on the pre-flash and the light is gone before the photo is taken.

Hopefully the Sigma flash will handle PTTL. I don't know enough about those, but I suspect a wireless compatible flash without PTTL would be rather useless.
You can control, from the camera's menus, whether the built-in flash contributes to the exposure or not.
Note, the built-in flash will always contribute some small amount even when "turned off"... that is how it tells the remotes to fire. So reflective surfaces may pick up the built-in flash regardless of that setting.

Dunno why, but I have yet to find the need to turn on the NR setting on the K10D. (I used to use it all the time on the istD).

Could be that I shoot RAW lately, but I've taken shots with 15 second exposures, and longer, and have not needed noise reduction. (some touch-ups of a few hot pixels) but I was truly amazed at the clear, smooth image that resulted. It could also be the nice job that SilkyPix does on RAW images (default settings).

I'm not sure the NR is worth the extra time between shots to make the dark frame subtraction. I guess I need to do some side by side tests... Too many factors changed in my process since I got my K10D.

I would sell my SLR and get a point and shoot. Little point in having such a camera and be limited to one lens.

For the sake of argument, the closest I would come would be for a no hassle, packing light, vacation lens. In which case I'd have to stick with my 18-200mm. As mentioned, sacrificing the flexibility would be difficult to give up.

But I would really miss my 50mm f/1.4 if I had to give that up permanently.

I think it is definitely a more than adequate lens. As one might expect, it is notably better than lets say the Sigma 18-200mm, although not necessarily as good as the Pentax DA* lenses (although not always significantly worse).

I have played with the 16-45mm briefly and although from what I've seen it is slightly better in many respects, you can hardly argue the price to quality ratio in favor of the 18-55mm.

Although I generally try to not add descriptive text. I do find myself guilty once in a while. I too prefer not to see a bunch of descriptive text that qualifies an image that might otherwise have little connection with the theme.

Yet I prefer the whole thing to be less stringent and kept on a more friendly atmosphere. I think the less rules, the better.

One can always refuse to read the text when judging. Admittedly, difficult to keep the brain from taking in more than you want, but hopefully you can also look back and say "I would never have seen that without the text" and throw it on the pile.

Man may leave his mark but nature will have other plans.

I have to agree. From the free version, I was almost turned off by the program's limitations. But there was so much being said about how good the program was I bought it anyway... and not sorry I did.

Their tech support has been quite helpful as well.
If the new download doesnt' help, I'd send them a support request through their support page.

See if this works,
http://shortcutinc.com/silkypix/win/SILKYPIX_WIN.EXE