Color to Color vs. Color Consistency

[arossetti]

Going through one of my printers Customer Expectation Documents and it references color to color registration and color consistency. Can someone explain to me what the difference of the two are?

[gordo]

Going through one of my printers Customer Expectation Documents and it references color to color registration and color consistency. Can someone explain to me what the difference of the two are?

"color to color registration" refers to one color overprinting another and how perfectly they land on top of each other over the course of the press run. Things are moving on a press so registration is never perfect so the colors will shift in and out of register.

"color consistency" refers to how stable the color is as solid ink density fluctuates over the course of the press run. As one ink density increases color gets darker, as one ink density decreases color gets lighter. As ink density varies between colors the printed color will shift hue.

Make sense?

gordo

[Cornishpastythighs]

I would be very interested to know what your customer expectation is for colour to colour registration and also their colour consistancy expectation. Is it +/- ink density or L*A*B?
Thanks

[arossetti]

Gordo - thank you, that is fairly close to my understanding but you are always able to shed more light on it.

Cornish - This was for a Xerox 700, I was trying to compare its expectations to our x800 but the CED for the 800 seems to cleverly leave out any specification when it comes to color.

Image Quality:
-As with any printing process, artifacts will occur. These may include fine scratches in the process direction, streaks, mottle, banding, spots, etc. For most jobs and clients, the expected level of artifacts is within the normal operational and component quality ranges of the system and will not affect the acceptability of the job. Maintenance procedures are available to mitigate these artifacts. Random artifacts will occur. Artifact-sensitive jobs should be monitored. Using products on the Recommended Media List (RML) and maintaining your environment will also help to minimize the occurrence of these artifacts.

-Color quality perception is subjective and will be affected by ambient lighting conditions. It is recommended that prints be viewed under a consistent light source, such as a D50 light booth.

-Like other color reproduction processes, there will be some variation of output quality over time. Factors contributing to this can include frequency of calibration (including calibration to the stocks being used), and xerographic components.

-Image quality is strongly influenced by paper surface structure, texture, and color. To ensure that your customers are optimally satisfied, key applications should be proofed on the Xerox Color 800/1000 Press using representative paper and reviewed by the customer.

However to answer your question:
Color Consistency is 7 deltae within a sheet, no guarantee for color throughout a run.
Color Reg is 86 microns measured on a 90gsm sheet.