Scanners and Monitors vs Digital Cameras

[pcmodem]

I recently heard that 2 scanners or monitors coming off the assembly line one after another will not match color the same.

Does this hold true with Digital Camera as well?

 

[Al Ferrari]

Of-course it does, and for the same reasons.

Al

 

[gordo]

Does this hold true with Digital Camera as well?

...and with lenses, and cars, and Starbuck's coffee, and Vegemite. All manufactured products are made to specifications which include some definition of a tolerance value for acceptable variation.

best, gordon p

my print blog here: Quality In Print

 

[pcmodem]

...and with lenses, and cars, and Starbuck's coffee, and Vegemite. All manufactured products are made to specifications which include some definition of a tolerance value for acceptable variation.

best, gordon p

So how can spectrophotometer's be reliable enough to read the same color from device to device and keep everything identical?

Thanks,
Brian

 

[meddington]

...and with lenses, and cars, and Starbuck's coffee, and Vegemite. All manufactured products are made to specifications which include some definition of a tolerance value for acceptable variation.

best, gordon p

my print blog here: Quality In Print

But at least we have color management for input devices. Not sure what they do for Vegemite

 

[gordo]

So how can spectrophotometer's be reliable enough to read the same color from device to device and keep everything identical?

The instruments get calibrated (brought to a known condition) using tools such as the X-Rite T-Reference card: Custom X-Rite T-Reference Card (which has some degree of tolerance for variation itself.

best, gordo

my print blog here: Quality In Print

 

[gordo]

But at least we have color management for input devices. Not sure what they do for Vegemite

You're not alone. No one knows what they do for Vegemite.

The question did get me thinking about what if car manufacturing was toleranced the same way as printing color?

Car salesman to purchaser: "Great choice of car model!
Now, this model does come in a choice of parts manufacturing tolerance. We offer "pleasing parts fit" our best price/value option - after all who cares about real precision except those calculator obsessed engineers anyway. The next level up in fit quality is our "memory parts fit" which is based on the assembler's memory of how the parts should fit. You can be confident about our memory parts fit option because all of our parts assemblers are memory-tested by the factory certified psychiatrist and must have memorized their multiplication tables up to at least 5 times 5. They also need to repeat from memory, with no help - at least one of their two telephone numbers. And finally our very best parts fit option, the "critical fit." This is for the truly discerning car buyer perhaps like you? Our competition cannot match us! They have no idea how we do it. For critical fit we use the best instruments available to assure a parts fit that meets the standard. Purchasing this option is a bit more complex than our other parts fit though, because we will need to work together to determine whether you would like the instruments to use the 1975, 1998, 2001, Six Degrees of Observer, perceptually measured or absolutely measured parts fit standards. Just between you and me, I have to disclose that our parts assemblers do sometimes ignore any standard reference you might embed in the purchase order. However, I'm sure that, in the unlikely case that you are not satisfied with the fit of all the parts in your car, a small discount in price will be sure to remedy your concerns and gain acceptance of final delivery of your car! And because you are such a nice person, we're going to throw in, absolutely free* an over all car gloss finish** that'll really make it shine!***. Sign here...."

best, gordo

my print blog here: Quality In Print

 

[Deleted member 16349]

So how can spectrophotometer's be reliable enough to read the same color from device to device and keep everything identical?

Thanks,
Brian

At the price range of graphic arts spectrophotometers, there will not be a very high degree of accuracy or agreement with different devices. It seems to be a common situation. For highly accurate readings there are laboratory instruments that are very expensive that would be required. Not practical for printing.

For printing one has to think of a practical solution for colour. Colour science is not an exact science. The Standard Observer which is based on the average visual performance of a group of people tested, is the basis for the functions used in colour science and in spectrophotometers. People do not see colour exactly the same way. It is called Observer Metamerism. One person might see two colours as being the same while another person sees them as being different under the same lighting conditions. I have read that the difference in people's colour vision can be on the order of Delta E = 2.

Any RGB input device (camera, scanner etc.) can not measure colour even if it has some kind of profile applied.

With all the limitations in dealing with colour, I think there is no point in being too picky. Especially when the variation in many processes is probably larger than the error between target and average. That is my guess.

I would also suspect that a customer will complain more about variation in the job than in having a consistent result that slightly misses the target. That is also a guess. Although I also guess that customers can complain about anything they want.