Datacolor User to User Support Group.

Is there a ball park time limit in between calibrations?

As an example if I print out the three sheet 729 patch target, is there a accuracy problem 
measuring the first target and then measuring the next target 10-20 minutes later? 

Would I need to calibrate the spectro before each target if a reasonable time has past?

Thanks,

John V

John, we reprofile about once every 60 days, or if there's something that
has changed beyond the typical ink cartridge or roll of media, such as a
service call.

This seems to be enough to handle the variation in media lots, ink lots, and
also keeps us in check with the studio temp/humidity.  

My studio is in an old house without air conditioning, and steam heat
radiators.  Even though I use humidifiers in the winter and a floor-standing
air conditioner/dehumidifier, the swing in temp/humidity between winter and
summer is pretty extreme, and definitely affects printer performance.  I'm
envious of anyone that has a nicely controlled environment...  

If you're reading the 729 patch with the PrintFix Pro spectro, it obviously
takes some time, so you might want to adjust your frequency based on the
time you need to do a new profile.

As to multi-sheet patch sets, I would strongly suggest making sure all the
sheets have been allowed to completely dry, maybe even overnight.  Of course
it depends on the media/ink combination, but if you do the first sheet right
out of the printer, and continue from there, you're likely to have some
slightly inaccurate color points  in the profile.

Calibrating your spectro can be done anytime, in theory.  CDTobie can
probably tell you the amount of drift, but I wouldn't think it is enough to
have to recalibrate the spectro between each sheet, I would read the entire
profile just after calibrating the device.  Other than that, there should be
no reason you can't calibrate as often as you want, certainly from day to
day.  

I used to use Kodak Colorflow for building profiles, and when the software
started up it would tell me if it had been over 6 hours, and it wouldn't
proceed without spectro calibration.  I don't know where they got the 6-hour
thing, but is a reference point of some kind.  (this was with X-rite dtp-41)

Just my 2 cents...  your mileage may vary.

-kris

> -----Original Message-----
> From: colorvision_group@yahoogroups.com 
> [mailto:colorvision_group@yahoogroups.com] On Behalf Of John Vitollo
> Sent: Monday, February 27, 2006 10:24 PM
> To: colorvision_group@yahoogroups.com
> Subject: [colorvision_group] Is there a ball park time limit 
> in between calibrations?
> 
> Is there a ball park time limit in between calibrations?
> 
> As an example if I print out the three sheet 729 patch 
> target, is there a accuracy problem measuring the first 
> target and then measuring the next target 10-20 minutes later? 
> 
> Would I need to calibrate the spectro before each target if a 
> reasonable time has past?
> 
> Thanks,
> 
> John V
> 
> 
> 
> 
> 
>  
> Yahoo! Groups Links
> 
> 
> 
>  
> 
> 
> 
>

"Kris" wrote:
> I used to use Kodak Colorflow for building profiles, and when the software
> started up it would tell me if it had been over 6 hours, and it wouldn't
> proceed without spectro calibration.  I don't know where they got the 6-hour
> thing, but is a reference point of some kind.  (this was with X-rite dtp-41)


Thanks Kris for the great info.

I'm using a hair drier to dry the targets before reading.

So my new question is regarding spectro drift: 

Can I calibrate the spectro in the morning and read targets all day?

Or do I need to calibrate the spectro more often than every six hours?

Thanks,

John

Thanks CDTobie! 

We crossed posted! 

--- In colorvision_group@yahoogroups.com, CDTobie@... wrote:

>
> 
> In a message dated 2/27/06 10:24:49 PM, jvlist@... writes:
> 
> 
> > Is there a ball park time limit in between calibrations?
> > 
> I assume, from what you write below, that you mean spectro calibrations.
> > 
> > As an example if I print out the three sheet 729 patch target, is there a 
> > accuracy problem
> > measuring the first target and then measuring the next target 10-20 minutes 
> > later?
> > 
> If there have been thermal changes in your room, it certainly won't hurth to 
> recalibrate from the Tools Menu. If its been four hours, the software will 
> force you to recalibrate in the Wizard as well. Recalibratioin has the added 
> advantage of warming up the device, as well.
> > 
> > Would I need to calibrate the spectro before each target if a reasonable 
> > time has past?
> > 
> Same answer as above; never hurts...
> 
> C. David Tobie
> Product Technology Manager
> ColorVision Business Unit
> Datacolor Inc.
> CDTobie@...
> www.colorvision.com
>

John, it can't hurt anything if you calibrate more often than less often.
The harm comes when the spectro has been subjected to different
temps/humidities/etc.  I don't know exactly what the variables are that
cause the spectro sensor to drift, but if your test standard hasn't changed,
your calibration will always bring the device into line.

-kris

p.s. I'm not sure I'd do the hairdryer thing.  The extra heat might cause
some extra shift.  Why not just print the targets and let them dry
overnight?

> -----Original Message-----
> From: colorvision_group@yahoogroups.com 
> [mailto:colorvision_group@yahoogroups.com] On Behalf Of John Vitollo
> Sent: Tuesday, February 28, 2006 10:42 AM
> To: colorvision_group@yahoogroups.com
> Subject: [colorvision_group] Re: Is there a ball park time 
> limit in between calibrations? Spectro that is!
> 
> "Kris" wrote:
> > I used to use Kodak Colorflow for building profiles, and when the 
> > software started up it would tell me if it had been over 6 
> hours, and 
> > it wouldn't proceed without spectro calibration.  I don't 
> know where 
> > they got the 6-hour thing, but is a reference point of some kind.  
> > (this was with X-rite dtp-41)
> 
> 
> Thanks Kris for the great info.
> 
> I'm using a hair drier to dry the targets before reading.
> 
> So my new question is regarding spectro drift: 
> 
> Can I calibrate the spectro in the morning and read targets all day?
> 
> Or do I need to calibrate the spectro more often than every six hours?
> 
> Thanks,
> 
> John
> 
> 
> 
> 
> 
> 
>  
> Yahoo! Groups Links
> 
> 
> 
>  
> 
> 
>