Jake Parker's new book will be out in September 2020, and he has posted some preview pages and video in an Instagram post.
I've watched the flip through video from Jake Parker and it looks good. It was only after I watched Alphonso Dunn's comparison video that I could see the similarities. It's not an exact copy obviously but there are similarities in layout and examples. Right at the end of Alphonso's video you can see all the notes and drafts he has made for the books.
Some in the comments section of Alphonso's video said that pen and ink techniques and concepts have been around since the Renaissance. True. Value scales in boxes have been around for decades, centuries.
So the differentiating factor will come down to the artist's unique style and interpretation. I've featured numerous books on Pen and Ink and while some may feature similar techniques, they are no where similar to Alphonso Dunn's book. I've featured even more watercolour instructional books and even when books have similar structure, chapters and techniques, ultimately what differentiates the books come down to the explanation of the concepts, more specifically the artist's personal take on the techniques.
The problem I see here with Jake Parker's book is his take on the techniques is quite similar to Alphonso Dunn's. My guess is Jake Parker probably hired a ghost writer for the book. And if he wrote the book himself, I would love to see the notes and drafts he made for the book.
Anyway, from what I can tell from the limited number of pages, the flip through video and Alphonso Dunn’s video, there may be some instances of possible plagiarism, but certainly not to the extent that Alphonso Dunn has claimed. Areas where it’s really questionable to me are the part where the light source shining on the blocks, and the list of unconventional tools is definitely heavily inspired.
I'll need to get Jake Parker's book myself to make the comparison myself. So far what I've said comes from what I've gather from videos and photos posted.