Re: i1Pro weirdness & fix
Re: i1Pro weirdness & fix
- Subject: Re: i1Pro weirdness & fix
- From: Ernst Dinkla <email@hidden>
- Date: Tue, 01 Mar 2016 15:07:46 +0100
Ben, Danny, thank you for the reassurance that this i1Pro is not behaving
that bad and for the explications on what I observed.
Met vriendelijke groet, Ernst
Dinkla Grafische Techniek
Quad, piëzografie, giclée
www.pigment-print.com
On Mon, Feb 29, 2016 at 5:07 PM, dpascale <email@hidden> wrote:
> Hello Ernst,
>
> I have a license of Patchtool but did not know this restore function.
>>
>
> It is not hidden but not obvious... (perhaps too much so!)
> It was placed in this "Info" dialog because this is where it was expected
> a user would go if there was a calibration issue.
> Such a check could be done at every calibration but I think that many
> users would feel uneasy by being asked for an impromptu lamp restore.
>
> Now for whiter than white measurements...
> There are three aspects to this question:
> 1- The intrinsic instrument precision. The instrument is not perfectly
> accurate and a certain amount of absolute and inter-instrument agreement
> errors should be expected. This is not visible when you are below L*=99 but
> it becomes obvious at L*=100.
>
> 2- The "heating" effect. As noted by Graeme and others, repeating
> measurements at short intervals may show an increase in measured L*. I have
> seen this effect for quite some time; my first souvenirs are around the
> time I manufactured "pure white" targets, i.e. near 100% reflection, where
> this effect is most noticed (and maybe more so for the older i1Pro). To
> control this effect when measuring fluorescence (as in the CT&A
> Fluorescence tool), I have been recommending a VERY METHODICAL procedure,
> waiting for instance 20 to 30 seconds between each measurement.
> (See for the AN-8 app note in this page
> http://www.babelcolor.com/tutorials.htm for more info)
>
> Note: I initially tought of an optical coupling interaction between the
> lamp and the optical fiber within the i1Pro but the Halogen cycle mentioned
> by Graeme makes a lot of sense.
>
> 3- Teflon is a strange material, not so much in terms of molecular
> composition but how its structure (and thus the manufacturing process)
> affects reflection. It has mentioned in the scientific litterature that
> certain forms of Teflon could be seen with more than 100% reflection, an
> effect attributed to a lensing effect of the sub-surface structure.
>
> Danny
>
> www.babelcolor.com
>
> ----- Original Message ----- From: "Ernst Dinkla" <email@hidden>
> To: "Graeme Gill" <email@hidden>
> Cc: "ColorSync" <email@hidden>
> Sent: Monday, February 29, 2016 9:13 AM
> Subject: Re: i1Pro weirdness & fix
>
>
>
> I had a gut feeling my i1 Pro (UV enabled) is reading too much reflectance
>> on whites now. I measured a new paper for SpectrumViz recently, the Arca
>> Proline Vibrant Superior Rag etc, that showed the highest white
>> reflectance
>> of any paper so far. I know it comes from Felix Schoeller and I have
>> similar papers from that stable that measure a bit lower in reflectance.
>> Platine category. There has been a steady improvement in inkjet coatings
>> whites over the years though. I got more alarmed when I measured a
>> plumber's Teflon tape stack of 5mm thick and the reflectance gave a Lab L
>> 100.+ where 9mm thicker stacks in the past did not go beyond L 99. I see
>> no
>> sign of fluorescence in the Teflon. This will not be the same piece of
>> Teflon tape I used before but I do not expect beyond 100 numbers in any of
>> them.
>>
>> I have a license of Patchtool but did not know this restore function.
>> Checked whatever could be wrong in my calibration of the i1 Pro,
>> calibrated
>> then and used the restore function of Patchtool. It soon gave the feedback
>> that no restore was needed, if should be fine. I still measure Lab L 100.3
>> on that Teflon, climbing to 100.5 on a fresh tape layer. Tested the i1 Pro
>> on some 3mm thick color acrylate samples I have stored. The new i1 Pro got
>> initiated on them in 2010 when it arrived and I stored the mesurements
>> with
>> the samples. Differences at most 0.3 (black) on the Lab L values of the 7
>> samples where I see 0.2 between measurements today. About 0.4 (0.7-0.1) in
>> time on the a b values.
>>
>> Conclusion: Nothing to worry about. This must be a very bright Teflon tape
>> sample and the i1Pro (UV enabled) is somewhat optimistic near Lab L 100 +
>> minute content of OBA in the Teflon, Lab b -0.1 in more than half the
>> measurements. Lab L 94 of the white acrylic sample is unaffected . The i1
>> Pro calibration white spot is fixed at Lab L 95.7. If it had aged and get
>> darker the white acrylic sample measurements should have showed that, no
>> change in the Lab L value though. The Lab b shifted 0.7 though either in
>> the calibration spot or the acrylic sample or both. I should have made
>> spectral plots of the two or three calibration whites here six years ago,
>> not just Lab numbers written down.
>>
>>
>> Met vriendelijke groet, Ernst
>>
>> http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
>> January 2016 update, 700+ inkjet media white spectral plots
>>
>>
>>
>> On Tue, Feb 23, 2016 at 2:13 AM, Graeme Gill <email@hidden>
>> wrote:
>>
>> Alexey Gribunin wrote:
>>>
>>> > By the way, just as an idea - is it possible to make special "cleaning"
>>> utility for i1Pro
>>> > and Spectrolino, which will turn lamp on forcibly for some seconds to
>>> "clean" it?
>>>
>>> Looks like X-Rite beat me to that -
>>> someone pointed out that there is a function exposed in BabelColor
>>> PatchTool
>>> called "lamp restore" that appears to use a new function in the i1Pro SDK
>>> (V4.2.2 or
>>> later). See <
>>> http://www.babelcolor.com/index_htm_files/PatchTool_Help.pdf>
>>> page 87.
>>> This sounds a lot like it is intended to deal with what I discovered.
>>>
>>> [ From my own limited experience with my instruments, I'm wondering if
>>> i1Pro2's
>>> are more prone to it ? ]
>>>
>>> It's possibly too that a recent copy of X-Rite's i1Diagnostics also
>>> includes such
>>> a function, although it doesn't seem obvious what or if it is doing this
>>> kind
>>> of thing.
>>>
>>> I'll add an option to ArgyllCMS spotread to diagnose and attempt to fix
>>> this
>>> problem in i1Pro's as well, and be a bit more up-front about what's going
>>> on.
>>>
>>> Graeme Gill.
>>>
>>> _______________________________________________
>>>
>>
>>
>
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