Thanks, Andrew for the quick reply. I make sure to use ACE. Learned that from one of your videos, which I have been gorging on lately. Need to understand more of this color management stuff beyond the rudimentary.
:Niranjan.
I can vouch for ACE's accuracy. Microsofts ICM, an alternative, is much less accurate.* "Accurate" is a term often bandied about without clear definition and is especially problematic when talking about color perception. I use the term here in reference to the ICC (color.org) which defines rather specifically the conversion processes used in matrix based profiles. Microsoft's ICM does a sloppy job of following them. LUT printer profiles use interpolation and the ICC does not specify the algorithms CMEs should use for those.
Also, while I'm sure Andrew has gone over this multiple times in his various video tutorials, indeed it should produce the same results. For those reading that haven't seen Andrew's stuff (which I highly recommend) here's what happens:
When you convert in Photoshop to the device's RGB space the values are those that the profile, as interpreted by the CME (Color management engine) maps to RGB values the printer uses to create the requested color, pixel by pixel. These RGB values are sent to the printer driver by ACPU without further color management.
When you use Photoshop to manage color, the exact same conversion occurs and the values are sent to the printer driver, also without further color management.
There is one difference with Windows. For unknown reasons ACPU prints a slightly smaller image. When you are printing to the printer's native resolution, 600 PPI for Canon, 720 or possibly 600 for Epson, ACPU will resample upward and duplicate every 20th pixel or so. It uses a nearest neighbor approach which can create tiny jaggies on near vertical or horizontal pictures. And, of course, there is the issue of printing the wrong size. I highly recommend using Photoshop manages color to avoid these issues. ACPU really should just be used for printing profiling targets.