I'm sure when working in Substance Painter, there have been times when you want to bring in a custom image for either a logo or just to add in some extra detail. As straightforward as it may seem, there is an ideal way to go about doing this to ensure you can edit it properly while in Substance Painter, especially when working with smart materials and masking.
The first thing you need to have ready are the images you intend to use. Before loading them in, you need to have them formatted properly. Substance Painter is very particular in how the images are setup. The first thing to do is make sure you have an image size setup. Substance Painter prefers that images are perfectly square, or at least the file that is. If you have an image that is say 1000 pixels long by 500 pixels tall, then you would need to make sure the image is on a 1000 x 1000 pixel background/format. You can up up the file in GIMP and adjust the size of the background, and then simply center the image.
As you can see on the example below. I have this image set to 1000 x 1000 pixels.
If you decide to skip this step, then your images will appear to be stretched when bringing into Substance Painter and placing on the model. It is a good idea to save the image as a copy somewhere and store in a place you intend on importing into Substance Painter whether it be a one time file, or an image you plan on using regularly.
If your logo/image does not have a transparent background, you need to make sure that you remove the background unless the image you intend to bring in doesn't have a background in it. This step should be done before you scale up the canvas size.
Below is the image, and you can see that I have already created the other layers for the alpha and background. This image will be saved as a png file type for the transparent background.
Once you have the image itself ready, now we need to worry about getting the alpha image ready. To do this, add a black background to your GIMP file. Once you have that completed, make a copy of your image within GIMP and change the color to completely white. This will provide you with the alpha image, all you need to do is export out your black/white alpha image. Make sure that this file is a jpg/jpeg file format.
When creating the alpha, you just need to fill in the image with white color or mess with some of the color settings until you get it to look like a solid color. These images should match each other from the color to the alpha and be the same size.
Now that your image is ready to go, all you need to do is import it into your project. Once imported in, make sure that you have them categorized properly for when we start to place it on the model. The alpha image needs to be set to type alpha and the regular image set to texture. This is more of a organization practice as Substance Painter will place it in the correct folder locations.
Now that we have the images into the project, we can start to placing it onto a model.
There are (2) ways of doing this and each has its own benefits depending on the style that you are doing or what the image type is.
The first method is creating Paint Layer.
This works best for when an image already has color and its not just an alpha image. You will be able to adjust some of the appearances on it, but you won't be able to edit it live. Essentially you place the image and if it doesn't look right you remove the image and make changes to the settings and place again.
Let's create a Paint Layer and then add in our texture and alpha into the correct fields. Now when we go to paint with the brush on the model, we can see our texture and how we want it to appear.
In the example below you can see that I have my texture and alpha displayed in the browser as well as having them loaded into the proper channels on the bottom right. The texture is in the color and the alpha image is in the alpha channel.
As you add in your image, it is good practice to slowly start adding in the channels that you want to use. The downside with just using the paint layer is you can't see what it will look like until you turn on each channel and make the adjustments within the Height, Normal, Roughness, etc. You may end up placing the object dozens of times while making the changes, but the final image will look good in the end.
The second method is by using the Fill Layer + Black Mask
This one works best if you have an alpha image as you will be able to customize all the channels live. I will use my logo above and only load in the Alpha as an example.
I have the height set to an extreme and unrealistic amount just so you can see what it looks like, but by using the Fill Layer and Black Mask option, you can adjust all color and other channels live and see what it will look like in the end.
This option works best for simple logos, images or text that you want to place on a model. Simply create your alpha, bring into Substance and then go through the Fill Layer and Black Mask option to adjust new texture as you see fit.
Again, work on the channels one by one vs trying to do them all at once. Start with the color, then add in some height and so on and so forth. This will help you get the look that are trying to find and not overwhelm you with information on the screen.