Quick way to see the visual changes between two images

[GarryP]

Note: This technique cannot be used as a ‘live difference check’ as it creates new layers that aren’t ‘linked’ to the other layers.

One ‘quick and dirty’ way to see the visual differences between two almost identical images (for example, maybe you want to see where you have made changes) would be to (in any Affinity application😞

1. Open the first image;
2. Place the second image as a new layer and move it so that it’s covering the first image;
3. Set the Blend Mode of the second image to Difference;
4. Right-click the second image in the Layers Panel and choose “Merge Visible” from the menu;
5. Add a Levels Adjustment to the merged result;
6. Set the “Black Level” and “White Level” of the Levels Adjustment to very small values (best actual values will depend on the image).

The result will show you where (most of) the changes have been made. (I have no idea how you might interpret the different colours.)

You can take this a bit further (only if you have Photo) by:

1. Rasterising the merged layer;
2. Inverting the layer;
3. Removing the White Paper.

See attached video where I have already opened and placed the images to save time. (I repeatedly toggle the Visibility of various layers at various points just to show what is happening.)

[PhoDesPub]

It's interesting to see how you can work with layers. As I said, in my case it was a much simpler comparison of two images, for example:
- where is the title better placed
- where is the centre object better lit
- which background colour matches the centre object better
etc.

So it's a visual, optical assessment of two ‘finished’ products. There should be a menu item for this, such as ‘Distribute images horizontally or vertically’.