A long article with few facts on the printer settings, image specs, media used.
The blue<>purple shift is a common problem in profiling and the discussed flaw is about the same hues. The phrases about the editing of the upsampled image may conceal where it went wrong, a bit more blue hue + a slight brightening and this article would not have been written:
"No problem; moving shadow detail is routine. A little tweaking of a curves adjustment layer, a little playing around with a hue/saturation layer, some masking to limit the effects to the areas I wanted. Nothing out of the ordinary."
Often enough I have seen identical image parts on my monitor drift in opposite directions in the print. And I do not think you can compare the numbers in areas like Ctein describes.
A printer internal LUT color management process might fit this image and the conditions it is printed in (upsampling or less downsampling, the editing) just a bit better on the details mentioned. In that case it would be interesting to see what a simple profile (less patches, smoother profile) could do in an application controlled CM workflow.
A very slight misalignment of the printer droplets can have an effect like that in the described areas. Target patch colors will not be influenced by that. A realigned printer may suite the custom made profile better. This is related to the discussion on what resolution to feed to the printer, aliasing or other resampling artefacts can play a role, either in the small print and adjusted on color for it to get it right while the large print would not need that correction or the opposite.
The original small print made with printer LUTs probably would have been too much shifted to blue in the eyes of Ctein.
Reading Joseph Holmes' workflow I wonder whether a PC printer server system running Qimage Ultimate is not an easier solution. I do not question his knowledge on printing. I have seen very nice prints he made. The workflow says that he lost confidence in Mac CM and avoids it as much as possible.
Reading the comments there the article could create new tribes that reject custom profiling, application CM or worse CM at all. That the image was saved by using the most basic printer CM does not imply that the flaw was in the CM part, Ctein could have added some warnings in the article like he does in his replies on the comments.
met vriendelijke groeten, Ernst
New: Spectral plots of +250 inkjet papers:
http://www.pigment-print.com/spectralplots/spectrumviz_1.htm