That's right, Space Marine Librarians need to be blue to work. All the modeling and all the painting in the world won't help if they're not blue. It may seem silly or petty, but it matters. Here's why:
That top image was my attempt at a Librarian using a technique I was developing a while back. It later turned into my Deathwing method, but I was trying to apply it to a dark blue model instead of light bone color. When I posted pics of him, nobody really knew what he was supposed to be. It was hard to tell what he represented on the table.
It all comes down to visual clues
I'm talking about those little things we all "know" as it relates to various armies in the 40k universe. We "know" Librarians are blue, we know Eldar have pointy heads, we know Tyranids have lots of arms and claws. They are stereotypical, but it's how we recognize things quickly and assign what we know about them just as fast.
Let's look at this guy here. He's got blue armour and that should help identify him as a Librarian, but it doesn't. His robes cover up the majority of it. He's got a psychic hood, but that doesn't do the trick either. He doesn't read as a Librarian right off the bat because of the weapon he is holding.
We know Librarians should have a long staff.
We know Chaplains should have a shorter crozius.
This weapon looks like a crozuis at first glance and our mind immediately sees him as a Chaplain. It doesn't matter that he has a psychic hood on or you can see his blue armour peeking out from under his robes... we've already made up our mind.
If you don't believe me, try this quiz here.
So how do we fix it?
Well, as much as I hate to say it, we feed into the stereotype. Unless we want to constantly answer the question, "What is he?" We'll need make sure our Librarians have a suitable looking weapon and are dressed accordingly. Looking the part is important if you want others to recognize what you're setting down on the tabletop.
Now that I say this, if you're doing an extensive "counts as" type army, this is not going to work. You'll end up explaining what things are as folks aren't going to recognize what anything is to begin with.
I rebuilt this model to help my friend
My friend ending up sending the model back to me and asked me to "fix it" so he could continue to use it as a Librarian and not have to explain what model it was before every game. I decided to make some modifications to the model with his permission in order to bring it more in line with what people recognize or imagine when it comes to a Space Marine "Librarian."
The first thing I did was order some new bits for him. He needed a longer staff and I wanted his other arm to look as though he were casting a spell as only Librarians can do. I ordered the bits I needed from Spikey Bits after talking to him about my project. Come to find out he's not too far away from me and he was able to get me the specific pieces I needed without it costing me a fortune.
And here's the new model. You can see a tiny bit more of his blue armour, he's holding an iconic Librarian staff in one hand, he's casting a spell as only Librarians can do with his other hand... this guys fits the bill perfectly now.
The new weapon looks like something a Librarian would be holding. The extended arm with no weapon and only a hand gesture is another iconic Librarian element. These two simple changes have made the model into something else. He no longer reads like a Chaplain, but looks like a truly powerful psyker now.
I'm hoping my friend no longer has to answer the question before every game now and his opponents recognize what he's got on the table. I'm not sure what else I could do to it at this point if he sends it back again.
Make sure to check out these posts as they might help:
A must take painting quiz
Did I paint my HQ model wrong?