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How can I save my alpha channel using Photoshop?

#1
So I'm trying to figure out metallic/roughness maps in Unity and I need to make an image with a custom painted black and white alpha channel, but I am running into problems saving it.

What I need to do, is take a roughness map and have that be the alpha channel of my metallic, but I am running into problems.

I've taken the roughness map I included here and pasted it as my alpha channel of the included metallic map in Photoshop, but unity doesn't like PSDs being used as metallic maps, and any .tga or .png I try to save will save WITHOUT an alpha channel.

I've been stumped on this one thing for over a day now and figured there has to be someone online who knows how I can save a readable image format with an alpha channel. I've done it before with my own images I've drawn, but for some reason I can't make alpha channels work anymore.

Any ideas on what step(s) I am missing?

PolyPlane_phong1_Metallic.png

PolyPlane_phong1_Roughness.png
 

IamSam

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#2
Hello and welcome to PSG.

OK. This is a Ps forum and not a Unity forum. We can't help you with Unity based problems. Try here: https://forum.unity.com/

What is a metallic map? What is a roughness map?

Explain how your trying to use alpha channels with two simple layers.

Screen Shot 2018-11-10 at 11.22.22 PM.png
 
#3
Hello and welcome to PSG.

OK. This is a Ps forum and not a Unity forum. We can't help you with Unity based problems. Try here: https://forum.unity.com/

What is a metallic map? What is a roughness map?

Explain how your trying to use alpha channels with two simple layers.

View attachment 93340
Heya. I figured it out

I took an image that I wanted to use as an alpha, went over to the channels tab in Photoshop, created a new layer (labels itself Alpha automatically) and pasted the image to the alpha channel. The problem was that when I saved as a png or tga, that Alpha channel wouldn't save with the file. It turns out I have to set the photoshop doc to RGB and when I save my .tgas, make sure I set them to 32 bits/pixel. The images I was starting with were grayscale and 24bits/pixel. This lets me save my .tgas with a custom alpha map

2f40b545436b3b697afae6870a04def3.png

Here is a gif showing the difference the alpha channel makes when it works. :) Gif starts with png version of the image I provided earlier, and then I switch to .tga version with alpha
https://gyazo.com/a1591ea6b38d39291c9ffc3b1fe44543
 

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