Re: Photographer needs monitor recommendations(Eye-One/iCColor)
Re: Photographer needs monitor recommendations(Eye-One/iCColor)
- Subject: Re: Photographer needs monitor recommendations(Eye-One/iCColor)
- From: "Bob Frost" <email@hidden>
- Date: Fri, 21 Nov 2003 18:56:38 -0000
Terry,
I was interested in what you say because, although I don't have an i1 - only
a poor little Colormouse, I played about for quite a while taking multiple
readings of patches and averaging them in Excel and correcting for drift of
the Colormouse in the not inconsiderable time that it took to read a whole
target. What I found was that the differences between individual readings of
the same point on a patch were pretty small in comparison to the differences
between patches. Different parts of the same patch did give readings that I
thought might be significant at first, but profiles made with single
readings of each patch did not differ from profiles made with multiple
readings - as far as I could see. I even started making alterations to
readings in Excel to see what effect they had, and the answer was altering a
single reading by quite a large amount had no obvious effect. I suspect the
'smoothing' that probably goes on in the profiling programs minimises most
of the small differences and some large ones if they don't fit the curve.
So I now make one reading of each of 729 patches, instead of three or more
of 125 patches. Lack of time and patience prevents me taking multiple
readings of 729 patches!
If anyone has an i1 that they don't want, I could give it a good home!
Bob Frost.
----- Original Message -----
From: "Terry Wyse" <email@hidden>
To: "ColorSync User List" <email@hidden>
Sent: Friday, November 21, 2003 12:24 PM
Subject: Re: Photographer needs monitor recommendations(Eye-One/iCColor)
>
on 11/20/03 6:33 PM, Graeme Gill wrote:
>
>
> Terry Wyse wrote:
>
>> transport time). Basing my data on 100 samples/second (Gretag's specs),
I
>
>> came up with around 20-30 measurements per patch on the IT8 and ECI2002
>
>> targets. Even if you cut this in half, that's still a lot of samples
being
>
>> taken. This amount of sampling would have been unthinkable on my
>
>> Spectroscan!
>
>
>
> What point are you making though ? Number of samples doesn't equate to
>
> anything in particular. 20 measurements of 50 msec duration are
>
> going to capture the same number of photons as a single 1 second
>
> measurement.
>
>
So, YOU'RE saying more samples per patch is no better than a single
>
measurement?
>
>
I guess my point was that when measuring inkjet targets that may have
slight
>
density differences across the patches OR when measuring a press/proof
>
target that has halftone dots, more samples per patch can mean a better
>
average of that patch. I don't have a scientific study to back that up,
but
>
intuition tells that SHOULD result in better data. It's just a hunch
though.
>
>
> The point of lots of measurements on these sorts of instruments,
>
> is that it allows them to detect the edges of the patches. Samples
>
> near the edges will be thrown away, and there will be dead time
>
> between readings. The spectroscan spends time moving the instrument.
>
> These things in themselves don't mean a whole lot. What's important
>
> in the end is the repeatability of the measurement.
>
>
Yes, some samples would be tossed out which is why I stated that, of the
>
20-30 samples/sec. the iCColor takes, if even HALF the samples were thrown
>
out that that's still a lot of good samples per patch. And, as I stated
>
earlier, the repeatability of the iCColor seems as good or better than the
>
Spectroscan in some of the informal tests I've made.
>
>
I will go on my merry way comforted by the fact that I'm getting several
>
samples per patch for free as opposed to the 1-3 samples per patch I used
to
>
get. Whether that's BETTER data or not is for someone else to decide. For
>
me, ignorance is bliss!
>
>
Terry
>
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