Hello All: Is there some "rule of thumb" regarding spectrophotometers and inter-instrument agreement? A situation can and has appeared where we are using an I1Pro measuring the IdeAlliance colour bar. When we read the chart/bar and have the printer read the very same chart using the same brand of spectrophotometer, same Rev., same settings, same backing, etc. we get different readings. Readings where our proof may "Pass" and their measurements will generate a "fail". Obviously this is an issue. What can be done about it? Thanks Mike Stewart
http://www.xrite.com/product_overview.aspx?ID=1912&Action=support&SupportID=... Inter-instrument agreement: 0.4 ∆E94* average, 1.0 ∆E94* max. (deviation from X-Rite manufacturing standard at a temperature of 23ºC (73.4ºF) on 12 BCRA tiles (D50, 2º)) Short-term repeatability: 0.1 ∆E94* on white (D50,2°, mean of 10 measurements every 3 seconds on white) Might be time for both sites to run the free i1Pro diagnostics. Andrew Rodney http://www.digitaldog.net/ On Feb 25, 2014, at 11:38 AM, Mike Stewart <mstewart@embassygraphics.com> wrote:
Hello All: Is there some "rule of thumb" regarding spectrophotometers and inter-instrument agreement? A situation can and has appeared where we are using an I1Pro measuring the IdeAlliance colour bar. When we read the chart/bar and have the printer read the very same chart using the same brand of spectrophotometer, same Rev., same settings, same backing, etc. we get different readings. Readings where our proof may "Pass" and their measurements will generate a "fail". Obviously this is an issue. What can be done about it?
Thanks Mike Stewart
On Feb 25, 2014, at 11:21 AM, Andrew Rodney <andrew@digitaldog.net> wrote:
http://www.xrite.com/product_overview.aspx?ID=1912&Action=support&SupportID=...
Inter-instrument agreement: 0.4 ∆E94* average, 1.0 ∆E94* max. (deviation from X-Rite manufacturing standard at a temperature of 23ºC (73.4ºF) on 12 BCRA tiles (D50, 2º)) Short-term repeatability: 0.1 ∆E94* on white (D50,2°, mean of 10 measurements every 3 seconds on white)
Might be time for both sites to run the free i1Pro diagnostics.
Indeed, also remove the filter attachment and clean it out. I've seen them fogged white with paper dust. X-Rite's (likely correct) response will be to ask when each of the instruments was last re-certified and recommend that they be sent back once a year…. regards, Steve
If you have an i1Pro 1 (Rev. A-D), you cannot remove the filter attachment without a high probability of breaking the mounting tabs (I have experience with this). The best you can do is to blow out the nose cone with a blower bulb (canned air might release its effluent into the nose). The new i1Pro 2 (Rev E) does have a user replaceable measurement nose with a glass dust shield that can be cleaned. While you have the nose removed, clean the lens too (read the manual for the correct procedure). If this does not improve your inter-instrument agreement, then you need to send the instruments back to X-Rite for recalibration or use a transfer standard and software, such as X-Rite’s XRGA system. Regards, Robin Myers On Feb 25, 2014, at 11:57 AM, Steve Upton <upton@chromix.com> wrote:
On Feb 25, 2014, at 11:21 AM, Andrew Rodney <andrew@digitaldog.net> wrote:
http://www.xrite.com/product_overview.aspx?ID=1912&Action=support&SupportID=...
Inter-instrument agreement: 0.4 ∆E94* average, 1.0 ∆E94* max. (deviation from X-Rite manufacturing standard at a temperature of 23ºC (73.4ºF) on 12 BCRA tiles (D50, 2º)) Short-term repeatability: 0.1 ∆E94* on white (D50,2°, mean of 10 measurements every 3 seconds on white)
Might be time for both sites to run the free i1Pro diagnostics.
Indeed, also remove the filter attachment and clean it out. I've seen them fogged white with paper dust.
X-Rite's (likely correct) response will be to ask when each of the instruments was last re-certified and recommend that they be sent back once a year….
regards,
Steve
While I am definitely not an official X-Rite spokesperson on this list I will re-iterate the most common reasons for inter-lab disagreement - some of which were covered, some of which you may only think have been covered. Before my list, Andrew is right of course there are stated tolerances in a well controlled metrology lab environment. X-Rite offers additional instruments like the eXact with even tighter specifications than the i1Pro if required. 1. Same device. Not just revision but particularly UV included/excluded hardware defined prior to the i1Pro2 2.Same software - Different software may actually change the values from the instrument 3. Backing - please don't say "self backing" please! 4.Cleanliness - The most common i1Pro "failure" in our repair facility as Steve noted is a dirty nose or a dirty or damaged cal tile. 5.Run Diagnostics - weeds out the most egregiously failing devices but is not a substitution for certification. The i1Pro2 also offers a more robust diagnostics capability. 6.Annual Certification - This is really the only way to absolutely know the instrument is behaving up to specification. Cheers, Ray Cheydleur -Mike Stewart asks: Hello All: Is there some "rule of thumb" regarding spectrophotometers and inter-instrument agreement?
participants (5)
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Andrew Rodney
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Mike Stewart
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Robin Myers
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Steve Upton
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