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rwb169
09-13-2010, 01:29 PM
Hi all,

We have a Xerox 700 with the EX700 Fiery controller. To Calibrate the machine we use the Kodak grayscale pack. Can anyone explain how the Fiery software uses a grayscale pattern to calibrate colour?

The calibration process measures the grayscale strip against a page that contains both colour and grayscale patterns. The colours on the printed page are not always in the same places. Is the Kodak strip even referencing these colours?

Would we see better results calibrating with the ES-1000 Spectrophotometer?

Cheers,

Confused

Lou_P
09-13-2010, 02:02 PM
The Fiery uses the Kodak scale to normalize the scan results so it can accurately read the color patches from the print for calibration. Because the scanner varies over time, scanning a known gray target the adjusting the scan data based on the scan of the Kodak strip improves the precision of off the glass calibration.

The scanner however is not spectral in its measurements, so calibration with an ES-1000 spectrophotometer will always yield more precise calibrations for the best results. This is the minimum recommended workflow for professional results, which are enhanced further by making custom ICC profiles with Color Profiler Suite.

Craig M
09-13-2010, 02:25 PM
I was just answering this when Lou chimed in. I couldn't have said it better!!!
Thanks, Craig

k_graham
09-14-2010, 12:07 AM
The Fiery uses the Kodak scale to normalize the scan results so it can accurately read the color patches from the print for calibration. Because the scanner varies over time, scanning a known gray target the adjusting the scan data based on the scan of the Kodak strip improves the precision of off the glass calibration.

The scanner however is not spectral in its measurements, so calibration with an ES-1000 spectrophotometer will always yield more precise calibrations for the best results. This is the minimum recommended workflow for professional results, which are enhanced further by making custom ICC profiles with Color Profiler Suite.

The problem as I understand it is the spectro is available with and without UV filter. I am going to suggest high white papers 95+ have UV enhancers so if you have a unit without UV filter - uh oh. Or alternatively if you have a unit with a UV filter but want to run regular bond or 90 - 92 bright coated - Uh oh.

I am guessing you would be better off with Color Cal to calibrate for bond or say 90 - 92 brightness coated than with a UV equipped Spectro. If I am not mistaken on my Doc 240 I am better off to Color Cal using 90 - 92 papers as using things like 98 bright hammermill will misread and resulting images will be too dark. However after having calibrated on the 90-92 papers reasonable results can be had printing on the Higher brightness papers. Though for some reason probably due to Adobes color Management it still seems wiser to print at 85-90 brightness settings.

In any event make sure a Gradation at copier is done before attempting to calibrate Fiery, if I recall it was also recommended to turn off and on the copier so a wire cleaning cycle could complete and to do any calbtration after the copier was running for a hour or 2.

If EFI wishes to loan me a Spectro or 2 I will confirm or reverse this theory that a Color Cal on 90 - 92 brightness paper works better than a UV filtered Spectro, but alternatively if anyone has a Spectro please tell us your unbiased findings - I might even be convinced to buy one if they provided me a trial. It surprises me users would use a Spectro yet technicians use a color chart - at least Xerox uses a human on the chart, not a butterfly for which only another butterfly can tell if its accurate as compared to pretty.

Another issue would be if the copier is even within specs to bother calibrating ie Measurement vs Target curves http://fieryforums.efi.com/showthread.php?t=1313

Ken

markdyck
09-14-2010, 08:47 AM
Hi all,

We have a Xerox 700 with the EX700 Fiery controller. To Calibrate the machine we use the Kodak grayscale pack. Can anyone explain how the Fiery software uses a grayscale pattern to calibrate colour?

The calibration process measures the grayscale strip against a page that contains both colour and grayscale patterns. The colours on the printed page are not always in the same places. Is the Kodak strip even referencing these colours?

Would we see better results calibrating with the ES-1000 Spectrophotometer?

Cheers,

Confused

I can tell you from personal experience on my 3260C that the ES-1000 makes a HUGE difference. I wouldn't recommend calibrating off the glass for anyone who would be somewhat concerned about colour. We used to just use the glass to calibrate and were always fighting colour, especially repeat print jobs. Once the we got the ES-1000, I can now be assured that when I print a job once, my reprint will look like the original (within reason as the machine gains wear & tear).

Hands down, since you're asking about the ES-1000, you should get one and you'll be happy for it.

Lou_P
09-14-2010, 04:49 PM
It is true that there is a challenge deciding which ES-1000 to get. For making ICC profiles it is important to use an instrument with UV filtration approproate to the substrates being profiled. So if most custom profiles will be made for plain papers, non-UV might be a good choice. Because most color-critical customers use higher quality sheets a UV filtered instrument is generally recommended. For calibration the filter makes less of a difference since it filters out a portion of the blue spectrum at the edge of human perception but does not make tones appear darker. Therefore measuring densites for calibration is not materially effected by the filter. In general, best practice is to use the same filtration configuration used to create the calibration. Default Fiery calibrations are all created with a UV-filtered ES-1000.

See http://fieryforums.efi.com/showthread.php?t=840&highlight=filter

k_graham
09-15-2010, 08:27 AM
It is true that there is a challenge deciding which ES-1000 to get. For making ICC profiles it is important to use an instrument with UV filtration approproate to the substrates being profiled. So if most custom profiles will be made for plain papers, non-UV might be a good choice. Because most color-critical customers use higher quality sheets a UV filtered instrument is generally recommended. For calibration the filter makes less of a difference since it filters out a portion of the blue spectrum at the edge of human perception but does not make tones appear darker. Therefore measuring densites for calibration is not materially effected by the filter. In general, best practice is to use the same filtration configuration used to create the calibration. Default Fiery calibrations are all created with a UV-filtered ES-1000.

See http://fieryforums.efi.com/showthread.php?t=840&highlight=filter

Okay, how does it compare to the previous Densitometer, as compared to the Spectro?

My experience was off the Glass or densitometer didn't make much difference IF the copier was able to make a reference test print off the glass the same each time before using the Fiery. What made a big difference was making sure the unit printed the same off the glass all the time which meant looking at something other than a butterfly test chart that Canon/Ikon uses, a photo of a woman in a white wedding dress being my preference. The skin tones looking correct but also any embroidery on the dress being visible and subtle grey shadows looking Greyish white - not blue, magenta or yellow. If the technician can leave that photo the same then it works - if not no amount of calibrating does the job (well maybe a Spectro?) . Let the color developer wear out and the fine detail is lost. You need to have a copy of the wedding photo, made from a machine the dealer is trying to sell new, such as when you first got your machine, and then give them heck when it they can't replicate it.

oxident
11-05-2010, 06:22 AM
I can tell you from personal experience on my 3260C that the ES-1000 makes a HUGE difference. I wouldn't recommend calibrating off the glass for anyone who would be somewhat concerned about colour. We used to just use the glass to calibrate and were always fighting colour, especially repeat print jobs. Once the we got the ES-1000, I can now be assured that when I print a job once, my reprint will look like the original (within reason as the machine gains wear & tear).

Hands down, since you're asking about the ES-1000, you should get one and you'll be happy for it.

Another interesting question would be how an old X-RITE DTP42 performs, compared between the simple color patch scanning and the expensive ES-1000.

On my DC250 and DC252, I'm not quite happy with neither the color patch nor the DTP42 calibration. Using the color patch method I can't get a neutral grey and with the DTP42, images (photos / renderings) become way too dark :-(

k_graham
11-30-2010, 08:17 AM
Another interesting question would be how an old X-RITE DTP42 performs, compared between the simple color patch scanning and the expensive ES-1000.

On my DC250 and DC252, I'm not quite happy with neither the color patch nor the DTP42 calibration. Using the color patch method I can't get a neutral grey and with the DTP42, images (photos / renderings) become way too dark :-(


With the color patch method you have the option of calibrating the scanner or skipping it. Definitely if having issues I would suggest calibrating the scanner first. In past history we used a IT8 scale to calibrate a Doc12 and CLC2400 and when this failed to allow the IT8 scale to print out properly we had to the technicians change the scanner light and on both machines this corrected the issue. Bulb changes we required in a little as 100,000 copies.

Strangely they both functioned okay a copiers with off the glass copies and you should first make sure they are making good copies off the glass before attempting to calibrate the Fiery, greys printing grey off the glass, - if they are and using the Fiery scanner calibration color reference doesn't fix it ask for a replacement scanner bulb.

Note. density strips should be placed on glass text as per sample print out from color scanner calibration sheet.

Regards DTP41 - on our DTP31 it is necessary to calibrate the DTP31 with a density strip that runs through the reader - what shape is the density strip in?

With either of the above methods I suggest calibrating and doing a gradation adjust with lower brightness papers in 92 or under range to avoid papers with UV whiteners.

Ken

k_graham
12-07-2010, 01:40 PM
Okay I recently took Markdycks advise and purchased a Spectro with color profiler.

Is anyone else on this list using a Spectrometer to manage color & create paper profiles, specific issue Cast Coated 12 pt. Xerox Gloss Cover on a Xerox 240 or 252?

On Coated Heavy Cover the reader has difficulties with recommend settings, reads 1st line. Colors specifically dark blue look mottled. Xerox tech support has'nt an answer yet.

Are you having troubles reading Cast Coated 12 point stock using Coated Cover settings with your
Spectrometer?

--I'd like to talk best practices - you may call me toll free1-800-317-8471 from USA or Canada

Lou_P
12-07-2010, 01:50 PM
First, please confirm you are running CPS 3 and have updated via the Web.

When you Print Patches, in the window where patch set and instrument are selected there is an Expert Settings button. At the bottom of the Expert window are you setting "Optimize Calibration" or "Use Current Calibration"?

Lou

k_graham
12-08-2010, 08:01 AM
No I am not running 3, I've let it update to latest version of 2.

I am setting to optimize calibration as it was the recommended setting.

I did have some success last night by reducing maximum ink levels to minimum and doing the 1 page print out - it seemed to get rid of the blotchy patches - but the results were worse than using the default Xerox , coated 2 setting.

Thanks in advance. Ken

Lou_P
12-08-2010, 06:32 PM
Ken:

You have a situation where Optimize Calibration is not ideal. You need to be pre-calibrated so that the profiling patches will be readable. Try this:

Calibrate using the coated media cal set that closest matches they media weight range they are using:

Coated 1 105-176 gsm
Coated 2 177-220 gsm
Coated 3 221-300 gsm

Then print profile pages using the "use current calibration" option in Expert. When printing the Profile Pages, be sure to select The "Media Type:" that matches "Coated 1", "Coated 2" or "Coated 3" setting used during calibration.

Please let me know if this helps.

Lou

Lou_P
12-08-2010, 07:19 PM
Ken:

An extra step to bu sure this works:

To be sure you get the correct calibration goals embedded in the new profile, please set the output profile associated with "Coated 1", "Coated 2", or "Coated 3" as the server default in color setup before you import the new profile. There are cases where you are not asked which calibration to link to a newly imorted profile and this guarantees that the right one is embedded.