cycles: problem layering multiple alpha maps

Support Materials and Textures
1

I want to achieve a parchment with writing on it, where the 1. letter has a different material (glossy shader, gold) than the others.
The scene consists of a plane which has a node setup to show parchment, then on this plane I add 2 Image Textures, alpha mapped png, one containing only the first letters, the 2nd only containing the text without the first letters.

The individual layers render correctly, but I have a problem combining the two alpha maps.

Here is my node setup for the alpha mapping (the pink rectangle is only a help to see the black writing and check that the alpha mapping works correctly):

scr0001.png800×800 286 KB

Now, I would have expected that combining the two alpha maps with a Add shader would do the trick:

scr05.png912×903 203 KB


As you can see, the 1st letters seem ok, but the text is half transparent. Obviously the Add shader multiplies the alpha with the text, which is not what I want. I want completely opaque letters.
I tried the Mix shader, but gave similiar results. I tried to use an rgb-add node, but this gave a completely black paper no matter which mode I selected.

In these renders I ignored the parchment layer.

Can anybody help me with this?

regards
Joachim

2

Here is how I deal with layered materials – I use black and white jpeg (or .png) masks. I like doing it this way because it allows me to adjust my materials/colors in blender. I made the main ink color blue, to sort of hint at the fact that using the mask approach you aren’t locked into the color from the image texture. This is what it looks like: (and yes, that is a sad excuse for a gold shader)

layer-nodes.jpg1366×1080 438 KB

3

Thanks a LOT! This is very helpful! May I ask where you got the parchment texture from?

Still, if somebody also knows how to solve this following my original approach, I would be glad! For the ink I agree it is a good option to use blender materials, but for the gold letters, I plan to use some effects from Adobe Illustrator that would be difficult to reproduce with blender technics.

I also would just love to know the techics to understand and exploit the system!

Joachim

4

you can alwasy do you texture in other soft save it as jpg or png then re use it in blender
but you still have to make masks

another way would be to make real alpha map in GImp

try it with the real letters texture you want and show us what happen!

happy cycles

5

I am not sure if I understand. I AM using 2 different images with alpha channel (png) and use the alpha channel to mask the image and that works fine (see first image with node setup, “render result 2” and “render result 2”). I only don´t get how to combine two masks into one.

6

I think you want to do something like this, this uses the png rgb colors for the diffuse shader, and the alpha for the mixing. You could do the same thing with the rest of the text if you want.

The parchment texture is one of the first google images for “parchment” I think it’s from this stock company: (I cropped it at 512 px)

layer-nodes2.jpg1366×1080 437 KB