Comparison shots 'Perfect Viewer' before and after the settings tweaks:
Before / After:
What actually happens (after image not converted to greyscale), and recommended settings:

(No app long press settings enabled, A2 of course is disabled, screen transitions in Perfect Viewer are still enabled. edit: As you can also see, I enabled sharpening in Perfect Viewer as well - but that depends on content and taste - add as you see fit.)
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Reuploaded the short smartphone video of Ivona TTS (english) to vimeo (turn up volume

).
For those of you who havent set it up already, here is the tutorial:
https://www.mobileread.com/forums/sh...&postcount=238
I encourage you to do it.