This is true on a lot of spiders Z. Me and Ruan did have a brief discussion on P ornata's I have/had. Some are much darker in color than others, some very light. (I sold the lighter colored ones this week actually). Can you post some pics of the different "color forms" of these H lividums? would love to see the difference between them.

I might be completely wrong, and have the cat by the tail. But at the first tarantula auction there were a H. Lividium and if I'm not mistaken Fuzzy said that it were one or other color form. Please slap me Fuzzy if I'm wrong here.

Never the less here's a pic of my Female, think it's the darkish light color form.
She's beautiful, such a pity it's a pet hole.

A while back i had a blue curly (we all remember,right ruan?)
i now see we have copper curly hairs,one with silver shade etc. its the same spider, in the next molt they will have a different shade and also the hair get a diff. shine with age....
we have ALOT of H Lividum all blue but none comfirmed females (yet), i have two mature females (one with a egg sack) they never stayed the same blue, with the next molt it change between dark and light blue and a shine and no shine and we have 3 mature males that are dark grey and a lighter grey.
(dont think this helps but its my 2cent) i do not believe in colour form anymore,if you have a black H.Lividum its sad,if its bright blue then just be happy.

Well, well, well.

Now I feel silly, bought two H. Lividium juvies last year some time.
One matured into a male some time back. Female were still a tad small to mate.
She also did not have full coloration, the brown/blue norm.

She molted a while back in her burrow and never saw her for a while.
Surprise surprise, she came out of her burrow last night and?

Pitch black, not even a shade, shine or glimpse of blue.

Now I knew that it was suppose to be the dark color form, but hell. That's damn dark

Post some picture for us.