Canon iPF8400 gamut reduction after 2 months of printing

[samueljohnchia]

Thought this might be interesting to share. I've been tracking the behaviour of my Canon iPF8400 printer since I bought it brand new in late February this year. I've been noticing a noticable loss of gamut since day 1 compared to prints made now. Something in the region of 5% loss of gamut. I made absolutely sure to agitate the ink carts carefully and thoroughly during the initial install, but this observation is made. I can't imagine why!

Apparently I'm not the only one to notice this with a Canon printer. Here is a report from an iPF6100 user in 2010.

I have also heard about small losses of gamut if inkjet carts remain in the printer for a long time. Manual removal and agitation or physically rocking the printer to prevent settling will prevent such shifts.

Wondering if anyone else has noticed such a thing?

[Geraldo Garcia]

I also bought one IPF8400 in February and can tell you for sure that we had no loss of gamut. I am sure because we just re profiled a paper with the same settings and compared the results: Almost no difference at all, actually a very small (less than 1%) gamut increase, most likely a spectrometer read to read variation.

Have you performed the initial calibration with the supplied paper during the install? May be be a good idea to redo it and see if it improves/restores the gamut.   

[samueljohnchia]

I've performed the initial calibration before I did anything, and I have recalibrated the printer 5 times since (and many more times of printing targets, measurements and re-measurements to the same paper to confirm my results.

Very weird stuff. Maybe its the changing humidity that is causing this. Its warmer and wetter this time of the year than when I first got the printer.

[darlingm]

Is it the same ROLL of media?  Some manufacturers aren't great about keeping their whitepoint stable which can cause this.  I have to re-profile one canvas manufacturer's canvas every few months because it keeps changing........

[digitaldog]

How are you comparing the gamuts? It should be by analyzing the ICC profiles in something like ColorThink.

[samueljohnchia]

Is it the same ROLL of media?  Some manufacturers aren't great about keeping their whitepoint stable which can cause this.  I have to re-profile one canvas manufacturer's canvas every few months because it keeps changing........

Yes, same roll of media. And its paper, not canvas which is inconsistent even withing the same roll... I've tested this with Canson Platine, Rag Photographique, Harman Gloss...etc.

How are you comparing the gamuts? It should be by analyzing the ICC profiles in something like ColorThink.

ICC profiles built with the exact same meausuring hardware (passes i1diagnostics), exact same profiling software (same version and same profile settings) and analyzed in ColorThink.

I've even resorted to heavier inking to see if I can top the initial gamut plots of early ICC profiles I've made for the printer. I get quite close, but I'm still 2-3% short of the original gamut.

[digitaldog]

ICC profiles built with the exact same meausuring hardware (passes i1diagnostics), exact same profiling software (same version and same profile settings) and analyzed in ColorThink.
I've even resorted to heavier inking to see if I can top the initial gamut plots of early ICC profiles I've made for the printer. I get quite close, but I'm still 2-3% short of the original gamut.

Well that's the way to be doing it. Be interesting to load the measurement data into CT and plot vectors, at least you could see where the gamut issue is happening. Very strange.

[samueljohnchia]

Well that's the way to be doing it. Be interesting to load the measurement data into CT and plot vectors, at least you could see where the gamut issue is happening. Very strange.

I've had three sleepless nights on this already, scanning targets until my poor i1 Pro 2 head is slightly worn down from the friction. I think this may be contributing to the problem. A couple of months ago, I did a test to see how accurate my hand measuring technique was. The CT report showed a max difference of 0.8 dE2k. I've tried this multiple times, same paper, different paper, glossy, matte, different target sizes, patch sizes etc. All about the same. Within the past three days I find that I get as much as a 5dE of difference for the odd patch!! I've made sure to rescan multiple times until the measurement data is consistent (repeatable). Maybe its the i1Pro head not exactly floating above the paper at the same height anymore. I've heard of i1iO problems with head height and the i1 Pro's sensitivity to that.

I'm hunting around for a used iSis to see if I can eliminate the errors in the measurement step. But I can't go back to re-scan my old targets from when the printer was new because they are formatted for the i1 Pro 2.

[digitaldog]

The CT report showed a max difference of 0.8 dE2k.

That's nothing to worry about. About what I've seen on my unit too.

Within the past three days I find that I get as much as a 5dE of difference for the odd patch!!

That's not good!

[samueljohnchia]

But my i1 Pro 2 passes i1diagnostics, and in spot measurement mode its highly repeatable, very consistent. 

I'm holding back at the moment trying to think this out and see where the problem could be. I hate getting inconsistent scans, and it was not on my radar previously. I've known about the measurement inaccuracy of the i1 Pro + i1Profiler not being conservative enough about throwing out the bogus data from when the aperture is over two patches. Ethan Hansen has also mentioned at the iSis is slightly less accurate with i1Profiler than MeasureTool. but in the order of like 0.1dE. All insignificant differences.

I've almost given up. I've never had a problem measuring targets by hand for 6 years with the i1 Pro and now the Pro 2. I might sometimes do a simple rescan of the problem row. After four straight hours on measuring and re-measuring one target many times on Sunday, I nearly threw in the towel.

[TylerB]

Hi Sam, just a thought... our old Spectrocams gave inconsistent readings in scan mode with large charts because heat built up internally, which effected readings, possibly changing the lamp behavior or the sensor. I used to put it on the tile and recalibrate every other line. I don't know how that info would help you but it could be relevant the behavior.
T

[samueljohnchia]

Thanks Tyler. It certainly is useful information. That's what I was doing for the later part on Sunday and all of Monday morning. Actually the i1 Pro 2 now has a temperature drift compensation which is surprisingly good, so performing the calibration regularly between scans doesn't show much difference.

It really puzzles me how the printer's performance changed this much over such a short period, and I don't want bad measurement data to be contributing to a false conclusion. But I've been consistently getting less gamut after many experiments which makes me inclined to think it must be the printer. Maybe I didn't shake up the carts as thoroughly as I thought I did. Maybe it got much more hot and humid recently. I don't know.

[Geraldo Garcia]

Maybe I didn't shake up the carts as thoroughly as I thought I did.

I am sure that this is not the case because I have never agitated the carts from my 8400. The printer does it by itself a couple of times a day by pumping inks in and out of the tanks.
Must be something else.
 

[Ernst Dinkla]

I've performed the initial calibration before I did anything, and I have recalibrated the printer 5 times since (and many more times of printing targets, measurements and re-measurements to the same paper to confirm my results.

Very weird stuff. Maybe its the changing humidity that is causing this. Its warmer and wetter this time of the year than when I first got the printer.

Did you measure the calibration strips manually too as an extra check? Do you have some old ones lying around to see whether the heads lay down less ink or the printer's densitometer/calibration software is acting weird? Not to mention the changed method of calibration versus the iPF8300 single paper calibration might play a role here.

I doubt it can be pigment settling and a head that is laying down less ink should be more prone to banding issues too. If nozzles fail they are replaced on the Canon heads checked by another sensor than the densitometer I guess but as written it is more likely that banding shows if both nozzles and the sensor fail.

The basic voltage to the heads going down but still within the specs to keep error reports out? The gamut decreasing evenly over the boundaries or on specific hues? The old calibration target prints may tell that too.

--
Met vriendelijke groet, Ernst

http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
April 2014, 600+ inkjet media white spectral plots.

[samueljohnchia]

Thank you Ernst! This is absolutely invaluable information. I am facing some microbanding issue, but performing the feed and head alignment on every new paper I use eliminates the issue, except on Harman Gloss paper. It could be that subtly they are still there. I never realised that both issues could be linked, and then as you say maybe the head is faulty.

The gamut is decreasing evenly over the boundaries. I have the old calibration targets. Going to dig them out and scan them again.

[samueljohnchia]

Did you measure the calibration strips manually too as an extra check? Do you have some old ones lying around to see whether the heads lay down less ink or the printer's densitometer/calibration software is acting weird?

Ernst, did the manual measurements of old vs new calibrations. The new calibration shows less density for all colors except for black and yellow, which corresponds to the overall decrease in gamut based on ColorThink's plots. They are about 0.5 L* points higher. A and B values also smaller in the newer target so less saturation. Side by side I can just make out the differences.

I'm not sure if this could be considered a densitometer issue. The differences are within 2dE2k, so its within Canon's specifications.  Lump it! The densitometer should have a repeatability of less than 0.5dE. Anything more than 1dE means re-profiling should be done.

a head that is laying down less ink should be more prone to banding issues too. If nozzles fail they are replaced on the Canon heads checked by another sensor than the densitometer I guess but as written it is more likely that banding shows if both nozzles and the sensor fail.

The basic voltage to the heads going down but still within the specs to keep error reports out? The gamut decreasing evenly over the boundaries or on specific hues? The old calibration target prints may tell that too.

That's a brilliant observation. I was indeed struggling with slight banding issues. After multiple head adjustments (automatic, initial head adjustment as though installing a new head, and manual too) I see most of the issue goes away, but there is slight residual banding in warm browns, cyans, blues, purples. There might be some in the oranges and reds but I can't see it. Very very slight.

I showed the banding - its clearer on a printer profiling target - to the Canon tech who came the other day. He took quite a while to see it.

I don't get any error reports. What do you recommend to do? Should I ask the Canon tech to check the power supply? If that's the issue changing the heads alone won't solve the problem? I'll remember to ask him to check the head management and multi sensor anyway.

[samueljohnchia]

I am posting this information as an update to this thread, and anyone owning an iPF8410 (aka iPF8400) may take note:

I have owned two iPF8410 printers now, the second one being the replacement for the first. I observed an odd gamut shrinking issue with my first printer. That printer had many missing nozzles in the service mode nozzle check and micro-banding in the prints.

Now my second iPF8410 has obvious banding in the prints, and the service mode nozzle check is showing missing nozzles too. Gamut plots also show significant loss of gamut in many colors, and is steadily dropping from print to print. The normal model nozzle check is not a reliable data source to know if the printer is working properly or not.

Just this morning I was attempting to run some tests and checks on the printer and suddenly all the colors from the left printhead (cyan, yellow, magenta and matte black) stopped printing. Nozzle check still shows these colors are still firing which is very weird.

If you own an iPF8400 printer, do check your printheads by running a nozzle check in service mode. Cross compare your data by measuring the on-board color calibration printouts to see if the density is dropping over time. You might have a similar problem that I do.

Perhaps a database of paper+ink gamuts (with proper documentation on how the profile was produced and which color geek software did the gamut calculations) would prove useful to compare and note if our printers are performing up to standard. Dmax values alone are not enough. Something to think about for a future project.

So the count is two printers from different manufacturing batches with the exact same problem. I also noticed a printhead/inking delivery issue with my dealer's iPF6450 printer. That's three.

For the record I have 4.5 happy years with my Canon iPF8100.

[Landscapes]

Sorry I can't be of any help, but I found it interesting how you discuss the nozzle check from the service mode.  I started a thread about this exact same thing almost a week ago and I was surprised that nobody replied.

http://www.luminous-landscape.com/forum/index.php?topic=92917.0

Because the iPF printers automap the blocked nozzles, its hard to know how healthy your printhead really is.  After years of owning my printer, I was surprised that I hadn't run across this ability in service mode.  One day the printer just worked, next day it says the printhead needed replacing and I found this frustrating because there really was no warning.  I do wish Canon would say how many nozzles can in fact be blocked and hence remapped and of course also how close you are to using up all the remapping ability.

At any rate, if you have time, can you post a picture of your TRUE nozzle pattern from the service mode?  I only see an issue with my blue channel, it seems like there are lots of missing nozzles in the red outlined area, but perhaps "lots" is quite subjective and so I'm curious about what other people get from their true nozzle patterns.

[JRSmit]

Samuel,
When printing for an photo-exhibition to open this Friday, a couple of prints are printed on a 6450. And in that printing process we also had some banding. Turned out to be a tick box on the printer settings user interface on the computer where you can choose for something like fast graphics or so. Switching that off resolved the banding issue AND gave better colour.
Perhaps it is also turned on in your case?

[samueljohnchia]

Samuel,
When printing for an photo-exhibition to open this Friday, a couple of prints are printed on a 6450. And in that printing process we also had some banding. Turned out to be a tick box on the printer settings user interface on the computer where you can choose for something like fast graphics or so. Switching that off resolved the banding issue AND gave better colour.
Perhaps it is also turned on in your case?

Hi Jan,

I am aware of that setting as well as a couple of other driver and printer on-board settings that may potentially cause banding. My banding woes are not related to those. In service mode the nozzle check clearly shows nozzles that are not firing. Plus, the banding was restricted to two color channels only, Cyan and Magenta. The banding you are referring to would be present for all color channels.

I have been checking the dot pattern of these two iPF8410 printers under a microscope and I have to say they do vary quite significantly. It is very difficult to get them in an optimal state. When they are, the dot pattern is even better than Epson 9900 printers in some ways, and of course it looses in some ways too.