I have used Visolve for many years on my iPad, MacBook Pro, and iPhones 4, 6, 7 and 8. This is the best tool I have ever seen, or used to separate out colours in my pictures or on the web.
I can now easily pick out the red spots and lines, see red-lined text (which was indistinguishable from black to me) and differentiate different colours in graphs making this an invaluable tool.
Crash problems (from Apple updating its iOS) were fixed several versions ago.
This is my number 1 favourite tool which I wish was part of iOS.
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