Xerox 250, EFI Rip and Autogradation

[bhm8hwcm]

We have a 250 with EFI rip and Eye One spectro for calibration etc.

Whenever we calibrate we just print out the patches and read them in.

I believe the box itself also has an autogradation calibration but we never use it. Should we being doing this as well?

I always thought the RIP handled all the calibration and thought the autogradiation on the machine was for copying/printing off the glass (which we never do).

Also we have always had problems with inboard/outboard colour across the sheet when it comes to tints etc. Not sure if there are other cailibrations we are overloooking that might affect things.

Any thoughts?

 

[che.c]

Well I can't say much about the autogradation except that I've never noticed an appreciable difference when doing it off the glass.

However for the inboard/outboard thang, yeah you gotta live with that, pretty much. Check the drums, the dev tanks and although we've had the laser unit changed too there was all very little difference. Just the nature of the beast. I've heard some interesting jabber about the machine not being level and causing dev to pool at one side of the tank, and retransfer picking up toner at the edges of the sheet again, but to be honest I think it's just a problem you've got to work around.

 

[Lrecta]

Color Eveness

Color Eveness

Sorry for the very late reply to this. I'm spending my day reading posts before I joined.

I had a similar complaint from a customer running a 242/EFI bustled controller when she printed 4-up cards with solid backgrounds: the colors varied from one pair to the other pair (center to edge). After numerous service calls and replacement of all drums and lasers it was better but still not "exact" (like it was for the first 9 months that she had it). It was suggested that she try the "randomized" test pattern during the calibration (only available for ES1000/Eye One) and this solved her problem.

 

[overscan]

That's got me confused. I always assumed that user calibration only dealt with overall colour matching and not a variable calibration over the sheet?

 

[Lrecta]

The calibration is to determine the state of color on the machine: to my knowledge the Fiery Calibration doesn't change anything on the Doc, just documents how it is handling the lay-down of toner on that pariticular day and/or material. It then uses this info along with whatever icc profile you choose to determine what the final result will be. By randomizing the patches (printing the cyan in all 4 columns rather than just one for instance) it looks at reproduction potential across the whole sheet rather than in a 2 inch wide area. Hopefully, this averages out any hotspots in one color due to drum and laser aging. When a customer is complaining of very small differences (@ 2-3 deltaE) this can help to minimize these differences. The Xerox spec is 7 delta E evenness across the page for the 242/52/60 & 700.