How to subtract differences from similar images in order to obtain the background

Question

I have 4 images, all with the same original background, every single one of them has writing somewhere in the picture, if compared 1 to 1, the only difference would be the writing, I wan't to extract the pieces of background from each of the images in order to build the whole background back.

Image:

if all the difference are substracted, it can be achieved the background without text (and no contant-aware fill):

What I managed to do, which is really bad and time consuming:

1. Select -> Color range
2. Select all color from text
3. Select -> Modify -> Expand by 2 pixel
4. Delete
5. Merge all of them together

This will leave JPEG artifacts and also won't be a real substraction, there are probably a term for what I'm trying to do, but since I don't know how it is, I arranged this title.

Answer 1

This can be achieved with a Stack.

• Select File > Scripts > Load Files into Stack.
• Click Browse and select your images. Make sure to check Create Smart Object after Loading Layers.

Now your images have been stacked on top of each other and packed into a Smart Object.

• Make sure the Smart Object is selected and select Layer > Smart Objects > Stack Mode > Minimum.