Erase White Paper – Help File

[PaulEC]

A lot of people seem to fail to understand the Erase White Paper Filter in Affinity Photo. If you have a black (or other solid colour) line drawing it will remove the white background (this is it's main purpose). However a lot of people seem to think that it only removes the white background and don't realise that it actually removes all the white from the image. This isn't helped by the entry in the Help File which says:

In fact "all other colours" will loose any white element in them, which means, in practise, that they become semi-transparent.

The filter is working correctly, but the Help File seems to suggest that the result should be as shown in the centre picture above.

I would suggest that the Help File is amended or expanded to make it clear that all white will be removed from the image, not just pure white. Other colours do not "remain unaffected", they will loose their white content, which can make them appear to be completely different. (I used a greyscale image as an example, but the same principle applies to any colour image.)

I appreciate that some people may argue that, depending on your definition of "colour", the file file may be technically correct, but, ignoring semantics, the wording appears to me to be somewhat misleading.

[NotMyFault]

I did not understand how the filter actually works. My best way to describe it would be:

• it makes all pixels partially transparent and alters all color so that you would get the original layer if you add a pure white layer below the layer after erase white paper.
• it virtually delivered the colors a printer device needed to put on a white paper to create the original image.

[NotMyFault]

Another way to interpret this filter: 

1. After using EWP, you can add a fill layer in any color below the layer
2. The results shows what you would get when printing the image on a colored paper using the same color of the fill layer