There is no Alpha/ transparency. It's just an illusion because incidentally the same colors are used. Everything else comes down to layer transparency and blending modes plus possibly bugs in the GPU acceleration that mess with transparency...
I've tryed using several colors, also, as far as I know, the gradient effect doesn't allow me to use different blending modes.
I've tryed this effect with just one gradient on one solid, which didn't give me full transparent colors as I've appointed them.
The possible bug in GPU is possible, I've tryed to change the colors and it worked perfectly fine, as if there was a transparancy in the effect, it appeared to be stable.
I didn't try to purge my memory. I should've done that
Still thank you
If you want a gradient with alphas then use a Shape Layer filled with a gradient. There are lots of advantages.
Thanks for your time
I'm aware of this posibility and the advantages of the gradient layer style, I was just curious about this artifact and tryed to understand it, as I might've wanted to use it in the future.
Still thank you guys for your time, seems there is no real solution or it might be a bug I've been noticing.
I just hoped there was some kind of alpha attribute I didn't happen to know about.
Once again thank you guys for your time,
This is not a bug. None of the gradients you can generate with a standard effect that come with AE create an alpha channel.
If you want an alpha channel all you have to do is create a shape layer with a gradient fill and no stroke. Double click the rectangle tool to fill the comp panel in the same way a new solid would, and then edit the gradient fill. Full alpha channel support.
You can even add multiple gradient fills to a single shape and blend them with blend modes to create something like this:
This is not possible without a ton of monkeying around if you want to use 4 Color Gradient or Gradient Ramp. The other advantage is that you do not have to pre-compose a shape layer to use it as the source for other effects like Displacement Map or opacity maps for particle systems. I have not used any of the gradient effects since shape layers were introduced.
Thank you very much for your time Rick,
Sadly this didn't really answer my question. I've done more research and it seems I've missed an attribute: Composoting Options.
I didn't notice the Compositing Options within the Effects before. Within the Composoting Options I change the Effect Opacity,
with this change I was able to recreate this "artifact". I recently went from CS6 to CC2014, so I didn't knew about this option.