What do you make of this statement:

"Of the Space selections available [for ACR conversion], Pro Photo RGB has much to offer in 16 bit workflows, but until the vexing problem of the corruption of 8-bit files is solved with Pro Photo RGB, it is best to stay with the standard Adobe RGB 1998 color space." from the new Digital Photography: Fine Print Workshop.

I have found that the PhotoPro RGB colorspace in Photoshop Raw conversions shows less clipping in the light and dark areas (while working in 16 bit) than Adobe RGB.

I tried test prints on my Canon ipf5000 using the same 16 bit image with PhotoPro RGB embedded.
The first print was sent from Photoshop to the Canon print driver (8bit) using the Auto Color mode.
The second was exported from Photoshop to the Canon 16 bit plug-in.

The results from the 8 bit print driver were much less saturated with lower contrast while the print from the 16 bit plug-in matched the screen image. This may have not been a fair comparison but differences were noted.

Ignorance...

Unless he is referring to the possibility of banding and posterization - which of course _ALL_ 8 bit/channel files suffer the same risk from. I think the author of that sentence is parroting what he thinks he heard somebody else say and then "corrupted" what he heard.

So, pretty sure -HE- deosn't have a clue to what -HE- meant...

Sounds as if we should ignore that source, at least "until the vexing problem of the corruption of" [half-heard rumors] "is solved."

The corruption of 8 bit files by ProPhotoRGB sounds like nonsense or an out of context quotation, but one is more likely to encounter posterization when editing an 8 bit ProPhotoRGB image than one in a narrower gamut such as sRGB, as explained in an old article by the Master himself.

While I personally would never refer to anything George DeWolfe says as "ignorance" (he has certainly earned more respect than that), the point does require some explanation. I have emailed him and will post his response when he gets back to me (which may be awhile if past experience serves, he is extremely busy).