So just to start things off on the right foot, this is Vetrofond Light Cobalt, not Effetre. I don't know how similar Effetre Light Cobalt is, because I have not tried it. I'm trying to test more production colours than out-of-production to make this resource more generally useful, but I had two pounds of this and I needed to know how the reactions work and what the colour looks like and since Frantz seems to still have tons of this, maybe someone else will too.
Light Cobalt is a not-very-light royal blue. It's a gorgeous colour, if you like bright, dark blue. It reminds me of the colour of some ice wine bottles, although those are generally transparent.
It was weird for me that this colour was transparent when I pulled it into stringer because it's so very saturated. So, it's dark and it's saturated, but not as dense and opaque as it seems like it will be in rod form. The stringer, when used on top of other colours, looks perfectly opaque, like that whole transparency thing was all in my head. (it wasn't)
What a vibrant colour this is. Reducing it seemed to darken the colour slightly.
Silver looks pretty silvery on top of Light Cobalt. In the bead on the left, the silver seems to have just stayed where I put it, and then when the silver is reduced and encased, it looks like a soft silvery blanket under the clear glass.
This colour is fun with reducing silver glass. It has struck darker here in the bead on the left just like it did in the spacer I reduced, and my silver glass frit looks beautiful on top of it, in lacy shades of blue and green. In the bead on the right, you can see gentle lighter blue halos popped up around my TerraNova2 frit.
Light Cobalt is not a very reactive colour, but there are a few things to talk about here.
Where I used Light Cobalt on top of Tuxedo, there is a thin crusty whiteish line around the dots and stringer lines in a not-very-uniform way. Nothing happens when it's the Tuxedo that's on top.
There's no real reaction between Copper Green and Light Cobalt except that Copper Green seems to develop that yucky greyish sheen more easily with this colour.
When Light Cobalt is used on top of Peace or Opal Yellow, you can see that there is some bleeding of the Light Cobalt into the glass around the stringer lines and dots giving a blueish glowy effect. When Peace or Opal Yellow is used on top of Light Cobalt, it develops a light blue outline, which is really neat-looking.
These beads all contain Light Cobalt.