Stencilling with Alpha image (Cycles)

I’m trying to stencil silver words on a satin ribbon, but it’s not quite working out. It’s probably something obvious, but as a newbie, Cycles nodes still turn my brain inside out.

Here’s my failed setup:


The messagealpha image is a black and white jpg that’s been mapped to the ribbon’s message area vertex group. Currently, though, the whole thing appears silver. Am I misunderstanding what “factor” does in a mix node? Am I going about this all wrong?

Attachments


You’re using the alpha channel of the messagealpha image as factor. Problem is: If that’s a .jpg, it does not have an alpha channel at all… You have to use the color channel of that image instead or use another image format that can carry alpha information (e.g. .png).

facepalm

Thank you very much!!

In this case the alpha value you are referencing in the image input is for the alpha value of the image. Since your image is a completely black and white image with no transparency, you would want the color output and not alpha. If your image was black text with a transparent background then the alpha output would work, but not here. See the images below: The first one is half bw, half transparent. I used it as a mask for both materials and put screenshots of both node setups and how they affect the resulting render. (I did shop the two node setups to the one image, so its two different materials. Figured I didn’t need to upload two images.) Hopefully this will help you figure out how the two nodes differ.



Transparent effectively sets the transparent portions of an image to be one of the two inputs, so in an image without transparency you only have one input.