[High Pass filter and 16 bit images?]

@Lisbon @Ron P.

Thanks for the replies folks, much appreciated. Sadly I'm seeing quite a few issues that don't appear to be receiving any serious attention, Hardware Acceleration being one other. Never mind, I'll persevere regardless. @Lisbon Thanks for the macro, I'll give it a spin. If it doesn't work, well its a useful addition to my newbie library  Onwards and upwards.... 

[High Pass filter and 16 bit images?]

I'm quite new to Affinity Photo and I'm trying to make some use of the High Pass filter. Unfortunately, each time I use it I don't the results I'm expecting, especially when I'm following a tutorial video. The only way I can get it work 'correctly' is if I convert the image to RGB8 as opposed to RGB16 (or if I export the image as a standard JPG file). Is the HP filter supposed to work on RAW files too, because it isn't doing that for me. The attached file is an example of what happens when I take a RAW file into Photo, Develop it and then apply the HP filter with Vivid Light Blend Mode. It's the same issue regardless of whether the image is colour or B&W.  However, if I export the developed image to JPG and reopen it the filter works as it does in the tutorials I'm following! Advice please.