[argyllcms] Re: testing printer profile with a set of XYZ colours

  • From: Klaus Karcher <lists@xxxxxxxxxxxxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Sat, 29 Jan 2011 11:29:52 +0100

Hi Iliah,

you wrote:
Suppose I need to check a printer profile for reproduction of a set
of about 500 pre-determined colours; colours being defined as XYZ D50
2 degree.

As a first step, I filter off the colours that are out of gamut
using xicclu -fif -ia -pX

This is a pragmatic way to check if the colors are in gamut. I tried out others, but came back to it as it is quick and easy.

Please note that you have to use -fb (lower precision) or specify the original separation parameters if you want to use them with xicclu -fif. Otherwise you use xicclu's defaults (-kr, estimated TIL, no black ink limitation). Separation parameters may affect the gamut, especially in dark areas.

Next, for those XYZ that fall into the gamut I convert them to RGB
xicclu -fb -ip -pX

Why perceptual? Do you want to investigate gamut mapping?

From the RGB list I
make a target formatting to CGATS and using ColorPort, print it,
measure it, and compare resulting XYZ numbers to source XYZ.

I'm not quite sure what you are after. If it's just the profile you want to test, I'd skip the printing and measurement part and just complete ther "round trip" with another xicclu call. Otherwise you bring additional unknowns into play (printer repeatability, measurement uncertainty)

If you really want to test the complete workflow, you can of course also use Argyll's tools (printtarg and chartread) to create and measure the target.


Other related posts: