KM 6501 - Fiery - colour has never been right ?

natty

Well-known member
Hi,

We currently have a 6501 and are looking to put in another shortly.

In the 12 months or so we have had our current machine the colour has never been quite right.

There has been a magenta cast to everything (we calibrate regularly) infact the only time there isn't a magenta cast is when it is not calibrated.

Through a 3 colour grey (C 40% M 50% Y 60%) at it and it ALWAYS looks red.

We also have a problem with printing blacks and the only workaround is to turn off the colour profiling completely)

My question is, what colour settings are you running to get as close as possible to a litho (lets say FOGRA)

I have tried everything and it is just never right.

Can we fingerprint the press in some way ?

My concern is when we put in the second machine it may be different again ?
 

JoshB

Well-known member
Well, I always find it's easier to get help when you're about to buy something, so you've got that going for you. Bring up your concern and insist that before you can purchase another press you've got to resolve the off-color issue and see consistent results between the machine on your floor and the demo machine on theirs.

My thoughts on where to start looking for troubleshooting would be:

#1 - Try different papers. Maybe there's something about the paper you are using that's ruining your calibration?

#2 - If you get this trouble consistently on multiple papers, what about checking your profiler? The profiler itself can be off or damaged. Borrow one from your dealer's demo floor.
 
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Mike Bishop

Active member
I have the same exact issues

I have the same exact issues

I have had a KM 6501 C for about 10 months and I have the exact same issues. My RIP tower is labeled as a PRO 80, but I know that even the techs have had trouble determining exactly what version of the RIP it is. This RIP has incorrectly handled Spot colors and RGB files since it was installed. If I send a file over that has a solid spot color rectangular header with swirls made out of tints of the same spot color; the color in general and the swirls in particular look incredibly far off from the color they should be matching. This type of terrible color matching also occurs when the RIP is fed an RGB file. I have had reps from the company that sold us the product as well as Fiery on site to try to solve the problem, but the issue has never been resolved. I have simply been given "workarounds" that are inexact, time consuming and only serve to show that the product can not handle simple color conversion in the RIP.
I too have noticed at times that after calibrating the machine the color actually gets worse. I just did a job with a light blue sky in the background that became pink and purple after I calibrated for the run. Sometimes the color gets better as it gets further out of calibration.
It seems that the Konica can lay down decent color, but that it gets fed bad data from the RIP. Of course if these companies are selling the products as complimentary they should both work towards solving these issues. This pairing of 6501 and Fiery is not a mature, efficient product. There are real problems with this pairing that can not be solved by the companies own reps.
 
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Greg_Firestone

Well-known member
Is the color consistently off after calibration, e.g. is it always too magenta or too yellow, or does it vary? If there's no consistently at all, your out of luck no matter what steps you try to do. If you can at least get it to a consistent (yet incorrect) point, you might have a chance.

Greg
 

Emtri

Well-known member
Hi,

Through a 3 colour grey (C 40% M 50% Y 60%) at it and it ALWAYS looks red.

We also have a problem with printing blacks and the only workaround is to turn off the colour profiling completely)

My question is, what colour settings are you running to get as close as possible to a litho (lets say FOGRA)

Can we fingerprint the press in some way ?

1: The 6500/6501 has always had problems doing 3 colour greys as well as large light multi channel solids. If and where possible let your rip handle it as black only, often this will look better.

2: What sort of black issues are you having?

3: We generally run SWOP for our konica

4: Yes. Konica does sell a color profiling suit that allows you do build ICC profiles for you machine, this may be handy if you are running two machines, that way they can be matched.

Also what controller/rip are you running on your 6501?
 

Correct Color

Well-known member
There's always an answer.

The problem is finding someone who can sort of what it is, what's causing it, and how to correct it.

And unfortunately, all too often, whomever that person might be, they don't work for whomever it is you have available on your list of people to call to solve the problem.

We also have a problem with printing blacks and the only workaround is to turn off the colour profiling completely)

Then that would indicate that your profiles are most likely the problem. They certainly could cause just the issue you're describing. If your device profiles are off in relationship to your machine in a calibrated state, it's certainly possible they'd create just the effect you describe. And if others have the same issue then it sure sounds to me like the stock profiles for that machine just might be bad.

Can we fingerprint the press in some way ?

It's what I do for a living.


Mike Adams
Correct Color
 

jotterpinky

Well-known member
Our new printer KM 6000 also has the same problem. I've noticed most printers have a tendency towards one or the other color. The other Xerox printers I've owned have had either a pinkish (magenta) hue or a yellow hue as is the case with our 700.

The current Konica has always been pink but will not print a good red color, everything looks orange especially when compared with output from our Xerox.

We've calibrated to no avail, and even went as far as creating profiles to feed the rip for different paper types we commonly use. Rather than get us truer color this only served to make the color even further off from what we see on our offset presses despite having created profiles for the presses themselves and having our copiers simulate the color from the press. In my experience there is no magic bullet with color on these type of devices as they seem to vary widely even with regular calibration.

We have a brown color we run quite often for a chocolate company on our digital equipment and have taken to calibrating just before running it each time. Despite this the color of browns NEVER match without tweaking...seems as though the calibration does next to nothing as far as preserving consistency.

What I find hilarious is that our technician seems to think that calibration will fix a whole host of problems. One time we had a "greenish" bar printing at the head of every sheet for about two inches then it disappeared further down the sheet. His first thought was to "calibrate" to get rid of it. It's stupidity like this line of thinking that is the real problem with many of these independent dealers who know next to nothing about color or calibration. I think you are victim to one of these dealers as are many of us.
 

natty

Well-known member
Is the color consistently off after calibration, e.g. is it always too magenta or too yellow, or does it vary? If there's no consistently at all, your out of luck no matter what steps you try to do. If you can at least get it to a consistent (yet incorrect) point, you might have a chance.

Greg

Yes its fairly consistently wrong after calibration. Always too red.

I think as stated its what the profiles are doing which is the problem... If you just turn off the profiles it prints as a press should. Bearing in mind that of course the CMY colour of the toners doesn't match offset ink colour, which i guess is why they try to profile it to compensate, But the way the profiles are implemented is just wrong.

For instance, i guess they figured that for 100% cyan the konica produces naturally they needed to add some magenta to match offset ink, which is fair enough, but i have laid down 5% screens of cyan before and with the profiling on, you can visibly see magenta dots with the naked eye... Surely at such a low density there would be no need to add ANY magenta ?
 

natty

Well-known member
2: What sort of black issues are you having?

Well, the profiles seem to interpret images differently to vector art.

When you through for instance a file with a solid black vector background that has an image which has been flattened (say there is a drop shadow that has been flattened to an image in the middle of the black), the rip prints the vector black as pure 100%, but prints the black that is part of the image as 4 colour black, so we get this noticable box.

Turn the profiling off and it prints exactly as it should.

Roll the eyedropper over it in pitstop and the flattened black part of the image is 100% (which of course it should be it its just been flattened) ... But again its the way the profiles behave which breaks everything !@@!
 

Greg_Firestone

Well-known member
Yes its fairly consistently wrong after calibration. Always too red.

I think as stated its what the profiles are doing which is the problem... If you just turn off the profiles it prints as a press should. Bearing in mind that of course the CMY colour of the toners doesn't match offset ink colour, which i guess is why they try to profile it to compensate, But the way the profiles are implemented is just wrong.

For instance, i guess they figured that for 100% cyan the konica produces naturally they needed to add some magenta to match offset ink, which is fair enough, but i have laid down 5% screens of cyan before and with the profiling on, you can visibly see magenta dots with the naked eye... Surely at such a low density there would be no need to add ANY magenta ?

That's good that you can get some type of consistency after calibrating. After reading the other comments, I agree that it seems the profile may be the culprit. Is it using KM provided profiles or are you using a standard profile (ie Gracol or Fogra). You can definitely try to fingerprint the press after a calibration. You could take it a step further and try to implement a device-link profile if your trying to target a certain spec.

Just out of curiosity, have you ever tried creating a test file with solids and tints and compared the output with both color management enabled and disabled? If you run disabled, your colors and tints should be pure with no contamination from the other inks. You could also see how much dot gain your getting.

Greg
 

Correct Color

Well-known member
Well, the profiles seem to interpret images differently to vector art.

When you through for instance a file with a solid black vector background that has an image which has been flattened (say there is a drop shadow that has been flattened to an image in the middle of the black), the rip prints the vector black as pure 100%, but prints the black that is part of the image as 4 colour black, so we get this noticable box.

Turn the profiling off and it prints exactly as it should.

That's a RIP issue. Not a profiles issue or a printer issue. Usually what causes this is that the RIP sees the area around the drop shadow and the area immediately around it as a raster image, so it applies its raster rendering intent to that area. The areas outside of it are still rendered as vector, and that causes the difference.

As far as the machine printing greys correctly with profiles off, it's pretty simple. With profiles off, the machine prints grey using almost completely black. Since the RIP is sending the information in the file through un-colormanaged, and in the file the area is most likely predominantly black.

However, color managed, that same area to the RIP becomes a Lab value that passes through an ICC profile with some sort of black generation built into it. Typically stock profiles on CLC machines start the black very late, as in after L 50. So what that means is in the print with profiles on, that same area that's nearly all black unprofiled now is most likely made up completely of CMY, with no black in it at all.

What calibration does is attempt to make all a machine's single channels print--if not linearly--at least predictably. Then an ICC profile, built on top of that calibration and expecting it, characterizes exactly how the machine prints. So of course the profile is expecting the machine to print in only one state. That's the only state for which that profile is completely valid. And if the calibration is off by even a small amount compared to what it was when the profile was made, you'll get exactly the issues you're describing.

So there really isn't to me too much doubt that all your issues are caused by nothing more than a bad profile, or even set of stock profiles, and can be remedied pretty easily.

As far as these machines not being capable of being tamed, as one poster said, I can't say I agree. They have their limitations, of course, and they do have stability issues...

But surprisingly, what I've found is that lots of people simply use those excuses as just that, excuses.

Properly profiled and with a proper workflow in place, these machines can be made to produce predictable results.


Mike Adams
Correct Color
 
Our new printer KM 6000 also has the same problem. I've noticed most printers have a tendency towards one or the other color. The other Xerox printers I've owned have had either a pinkish (magenta) hue or a yellow hue as is the case with our 700.

The current Konica has always been pink but will not print a good red color, everything looks orange especially when compared with output from our Xerox.

We've calibrated to no avail, and even went as far as creating profiles to feed the rip for different paper types we commonly use. Rather than get us truer color this only served to make the color even further off from what we see on our offset presses despite having created profiles for the presses themselves and having our copiers simulate the color from the press. In my experience there is no magic bullet with color on these type of devices as they seem to vary widely even with regular calibration.

We have a brown color we run quite often for a chocolate company on our digital equipment and have taken to calibrating just before running it each time. Despite this the color of browns NEVER match without tweaking...seems as though the calibration does next to nothing as far as preserving consistency.

What I find hilarious is that our technician seems to think that calibration will fix a whole host of problems. One time we had a "greenish" bar printing at the head of every sheet for about two inches then it disappeared further down the sheet. His first thought was to "calibrate" to get rid of it. It's stupidity like this line of thinking that is the real problem with many of these independent dealers who know next to nothing about color or calibration. I think you are victim to one of these dealers as are many of us.


Which RIP are u using?

If Its IC-306 maybe i have a solution for this Red color issue in KM c6000 m/c since i have faced the same problem in my m/c.
 

ChrisD

Member
Two inch colour bar across the page

Two inch colour bar across the page

We have a KM6501 working for about 3 years, we found that when we run an offset sheet, SRA3 size, 350gsm, slightly over the specified weight we have the same problem. The other issue of colour may be due to the paper, I found that when we tried Xerox Impressions gloss most of the problems were resolved, but I must say that our KM engineer knows his stuff and seems able to adjust the colours for us. We bought the calibration kit, very expensive - to work with the Fiery rip but we don't bother any more, it seems better with no calibration.
 

BVulgaris

Member
stupid set of questions:

1. have you checked a colour band test sheet for density unevenness across the page?

2. what kind of rip/program are you using to send jobs to the machine?

also, in the print driver settings... expert colour mode.... are you using source GCR?


as far as spot colours, I seem to have the same/similar issue. Once it was due to a density unevenness that wasn't seen unless a 13 wide sheet was printed out... far right side had the right colour... anyhoo, mentioned it to the tech and his incredible diligence corrected the issue.
 

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