Transparent Texture

I have Texture A and B. A being an image and B being a solid black texture. I'd like to draw B over A, but have it be transparent enough to still see the image behind it. I'm not sure how to make the solid black be somewhat see-through. Is this something I'd do in Unity or the software I used to make the texture? Thanks!

Blending solid black over something is the same thing as multiplying all the pixels of an image by a constant. You can write your own shader if that's really all you need, and that will be extra-fast, but you can just use material.color for this, with the built-in shaders, with the same value for R,G, and B.

Use the built in transparent shaders and set it's alpha to < 100.