Different spectrophotometers readings

John is providing anecdotal information about inter-instrument variability. What I provided was one of the results of a research study performed by PIA/GATF. With all due respect I'll stick with the PIA/GATF on this one. It's a study that should be redone to see if any progress has been made to reduce the level of sub-par agreement they initially found.
 
I don't believe that measuring one area with two devices proves anything. Take a sheet and measure the same colour in five different places on the sheet (think five of diamonds... Once in each corner and then in the middle). I'd be amazed if anyone gets the same result across the sheet.

I'd agree.

Then I'd go a bit further and suggest taking those readings, averaging them together for each device, and then comparing the averages.


Mike Adams
Correct Color
 
Thank you Mike... Yes that is exactly what we do. It's not 100% perfect but it's the best solution we have found.
 
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Gordon, could you share the original document (pdf,ppt, ...) from where you copied this graph?

I don't know if that is permitted due to copyright issues.

You might be able to get it from the source(s).

The presentation was made at the 2007 Splash Color Management Conference

It was conducted by PIA/GATF - https://www.printing.org/

The testing was done by Greg Radencic, Research Scientist (at GATF at the time) Greg is no longer with the PIA/GATF. He’s now (I believe) at Schawk in Pittsburgh:
6515 Penn Ave
Pittsburgh, PA 15206
Tel: +1 800 836 5571
(http://www.schawk.com/)

He is LinkedIn here:
https://www.linkedin.com/in/greg-radencic-9b80066/

I hope that helps.
 
25 posts on instrument agreement issue. And no one mentioned xrga. How so?

Has it been adopted by all the vendors? Can it be integrated with existing instruments? Has it be independently tested? Does it eliminate inter-instrument disagreement?
 
thanks!
...the name of that file?

Sorry.

"Spectrophotometer Device Agreement Greg Radencic, PIA/GATF" It's a PDF and it has an associated "Spectrophotometer Device Agreement.mp3" file which is the audio of Greg's talk as he goes through the presentation.
 
Has it been adopted by all the vendors? Can it be integrated with existing instruments? Has it be independently tested? Does it eliminate inter-instrument disagreement?

Is XRGA anything else but X-Rites way of trying unify devices with different light sources?
 
Is XRGA anything else but X-Rites way of trying unify devices with different light sources?


Hello Johu,

I thought it was to unify the subtle differences in calculations within software/firmware of the devices ....

Anyway this is what X-rite say about it.
-
Making Color Measurement History

Back in 2006 when X-Rite and GretagMacbeth joined forces, it became apparent that the calibration standard differences would cause issues for our customers who wanted to use devices from both. X-Rite developed XRGA standards to merge these systemic variations so that all of our customers – regardless of legacy affiliation – can achieve high quality data exchange among instruments and sites.

XRGA delivers quality data exchange among varying sites and instrumentations and aligns calibration standards for XRGA compliant instruments from both X-Rite and the former GretagMacbeth. The XRGA standard is also available to third parties so that it can be applied to their instrumentation as well. With participation from third party instrument manufacturers, XRGA has the potential to optimize color measurement across the entire multivendor color network.

http://blog.xrite.com/xrite-graphic-arts-standard/


It looks as if X-rite offered up the standard to third parties. I have no idea who took them up on this offer.
 
Generally it is a mess trying to combine data/scans from spectros of different suppliers, my experience is to be able to align you should at least focus on only using one vendor for your spectros, even then you will have some variation if you don't have a very strict protocol following them up.

Know it only applies to X-rite stuff but what about their Netprofiler solution, done once a month it should align the spectros in a better way than the yearly calibration (which many time is overlooked as well)...? The netprofiler is to align spectros through the software so you don't need to send it in for smaller adjustments.
Are anyone aware of some similar product capable alignment across differnt spectros but is independent on the spectro brand?
 

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