http://www.ddisoftware.com/qimage-u

v2020.119      May 1, 2020

Priority: Med

2020.119 fixes a bug that could cause inaccurate color in prints when using "Let printer/driver manage color" under some printer configurations.

Mike

The decision is made per the description in the video I posted.  The algorithm looks at how much of the image is out of gamut and if enough of the image is out of gamut, it switches to perceptual intent.  The algorithm considers the colors that are out of gamut, where they occur in the image, and other factors and was tweaked using hundreds of images from various users/photographers.  It's an "automatic" feature so the actual metrics need not be known as I know other (companies) like to copy my work.  There is a possibility to add an RC/perceptual threshold slider in the future if needed.  For now, I think it best to allow people to use it and see how it is working for them before adding more complexity (and potential confusion).

As to the gamut check, Qimage uses the standard form of gamut check.  The standard color management tools (the tools I use and likely the ones other tools use) don't provide a way to see how far out of gamut an out of gamut color is: it's either in or out.  I agree that would be interesting to see but ultimately it wouldn't matter because out of gamut essentially means "clipped" so no matter how far out it is, you will lose detail there unless you use something like perceptual to scale it.

Regards,
Mike

The perceptual/RC selection is not picked until the printer profile is applied so to see what the auto setting picked, click the soft proof button under the live view and then hold your mouse over print(s).  The intent that the auto setting picked is displayed in the popup information when you hover over prints during soft proof.  Auto only affect rendering intent so set BPC to your preference.  I've found that BPC varies a lot between profiles (and profile-making tools) so it's not a good pick for an automatic setting.  With some profiles, you find yourself turning BPC off a lot because BPC causes a loss of contrast particularly on matte papers.  With other profiles, BPC seems to help every time.  So simply put, if you find that you have to turn BPC off for a fair number of images with the profile you are using, leave it off when using auto intent.  If BPC seems to do no damage and sometimes helps with your profile, leave it on.  And if you don't know: run some tests or just leave it on until you have a problem like your prints looking washed out at which point, you can turn BPC off to see if it improves contrast.

Regards,
Mike