Eric Fishwick, CLSA wrote:
- Is my understanding of what dispcal does correct, if so howdoes the icc profile add to this
dispcal creates calibration curves that are used to change the behavior of the display. profiling characterizes the resulting behavior. The calibration is typically embedded within the profile for convenience, so that the display will be put in the correct state to match the profile. See <http://www.argyllcms.com/doc/calvschar.htm>
- I used the -as switch (mainly because www. <http://www.marcelpatek.com> marcelpatek.com gave it as example) to generate a "shaper+matrix" profile. How does this differ from any otherkind?
It's rather technical, but it selects a particular profile model. Different models make different trade offs. A shaper/matrix model will be smoother and more exactly invertible than a CLUT based model, but will only accurately model a device that behaves additively (ie. the primary color channels don't interact). A CLUT base profile is more flexible in accommodating arbitrary device behavior, but being table based, adds approximation type errors.
- The Argyll docs imply that the .cal file (from the calibration) is embedded in the .icm file and is redundant, am I reading this correctly?
Yes. It usually gets placed in the 'vcgt' tag.
- For non-colour matched apps and the desktop am I right in thinking that only the calibration part applies ie I now have gamma and grey scale tracking correct but other colours might be off...
- And that for icc aware apps all colours should be corrected for the inaccuracies of the display (but corrected to what reference - Ishoot raw?)
Device color profiles allow transforming between colorspaces. To do this, two device profiles are needed, so the "reference" is the source profile used. This will usually be the profile the images are tagged with, or colorspace they are assumed to be in.
- Is Lightroom 2 such an icc aware application (I assume yes but can't find this anywhere in the LR help files).
Sorry, I don't have detailed knowledge of Lightroom.
One last question when I get around to profiling the printer.Colprof has an option to include a source icc, it has 2 switches and the help states: -s src.icc <file:///F:/Argyll_V1.0.4/doc/colprof.html#s#s> Apply gamut mapping to perceptual B2A table for given source -S src.icc <file:///F:/Argyll_V1.0.4/doc/colprof.html#S#S> Apply gamut mapping to perceptual and saturation B2A table Trouble is, I haven't a clue what this means. Which if any is appropriate? Or is this irrelevant and I should just calibrate the printer without a source icc profile. The printer is a Canon i9950inkjet, my understanding is that its gamut is greater than the screens.
The source profile provided is used to setup the gamut mapping incorporated in the profiles perceptual and saturation B2A tables (Profile Connection Space to device tables). Without a definition of the source gamut, the gamut mapping can't be formulated. So the answer is for you to provide a source profile that is the one you will be using when you make use of the printer profile as a destination, or one that is similar to, or typical of the source profile you will be using. For instance, if the images you wish to print are in (say) sRGB colorspace, then you would provide the sRGB profile as the parameter to the -s or -S options.
My purpose in this is to have what I see on screen in Lightroom (hichdoesn;t soft proof) as close to what I get printed as possible.
It's never really possible, since the devices have different gamuts and viewing conditions. The point though is to end up with the best possible reproduction, and the intent is a way of instructing the system what you mean by "best". Graeme Gill.