[argyllcms] Re: Limitations on Colormunki patch sizes?
- From: BC Rider <bcrider99@xxxxxxxxxxx>
- To: "argyllcms@xxxxxxxxxxxxx" <argyllcms@xxxxxxxxxxxxx>
- Date: Mon, 11 Nov 2013 22:57:26 -0800
> BC Rider wrote:
>
> > for a letter size sheet. This seems to be a very low number given the
> > physical spec
> > of 6mm measurement aperture. Why not 400, 600 or even 729 patches on a
> > sheet?
>
> Hi,
>
> The ColorMunki chart is designed to be usable with a normal ColorMunki
> instrument,
> and guiding it by hand across the patches is awkward to say the least. Of
> course
> if you think you have a means to guide it with more precision, you could try
> some other chart layout such as the i1pro, possibly enlarging it's default
> patches slightly depending on your setup.
>
> Graeme Gill.
>
Thanks. I will be making a sophisticated jig and can achieve whatever
precision is necessary, sub-mm if needed. If I'm going to make a scanning
apparatus I want to go as small as possible. What is the minimum patch size
that still retains full technical performance? 6mm aperture size?
I notice the illumination is about 25% wider than tall...but assume it is
within the 6mm spec?
The sampling aperture presumably isn't a brick wall at 6mm...do these devices
pick up much outside their specified aperture size? If so, then I'd need a
guard band (i.e. larger patch) to ensure it is seeing the same patch color and
not the adjacent one.
I understand the Munki takes many running samples and averages for each patch.
So presumably a 50% patch size will capture half the number of averaging
samples. Can I compensate by scanning half as fast? Are these things sensitive
to speed or speed changes?
Bottomline: So to put a number on it, let's say I build to an 8mm patch size
based on the i1pro layout (is there is a better one for this?). Anyone see a
problem with that? What do I need to know that I'm blissfully ignorant of? I
can build jigs...but I don't know much about the technical side of this stuff.
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