CHOCOLATE PROBLEMS?

I am not a Chef. I just a silly old guy who tries to make good chocolate at home. It is good, I enjoy it and my neighbours are actually paying for them. So I cant answer all your questions. However I will give it a try.

GENERALLY SPEAKING.
If you chocolate making environment is too humid, the chocolate will develop a sugar bloom.Humidity can also cause dullness.
If the temperature is not stable,this can happen if you have a smallish kitchen without air conditioning, then you may get white streaks. Which is fat bloom.
If you get it in contact with water, all manner of problems can interfere with your chocolate making.

DULL PRALINES

This happens when the praline centers you choose, nuts, raisins, apricots, nibs are too cool(especially if you have just pulled it out of the frig) or cooler that the chocolate you are going to mold. Centers must be as warm as your chocolate.Cooler centers form a condensation on the outside.

Chocolate can be dull if you molds are not clean.Use clean polycarbonate molds.Not cheap plastics.

Your chocolate can also get a dull look if over-tempered or under-tempered.
Chocolate can also get dull if you warm it too quickly after you take it out of the frig. In this case wrap it in towels and allow it to warm gradually.

Chocolate cooled in much too cold temperatures can turn out dull and even crack.

SHINY CHOCOLATE.

It is a result of proper tempering This comes from experience especially if you are doing it by sloshing your chocolate up and down, with a neat wood length, on a cool marble surface.If it is not tempered well it can get pockmarked, streaky and have sugar dust on the surface.

BUBBLES IN YOUR CHOCOLATE.
This is caused by too much viscosity. Probably due to too much emulsifier. You can add more cocoa butter or lecithin. Too much agitation during tempering can also cause bubbles.

If you have more questions be as specific as you can. I will try to give you reliable answers.