Correct way to perform calibrations? (Xerox V180 + EFI Fiery + CWS)

donster

Active member
Small progress update... had phoned/teamviewed with two xerox people and they more or less confirmed that the calibration process that I do is indeed correct. They mentioned that if we had Color Profiler Suite, it would all be much easier for us, but unfortunately - that is not the option.

The worst result we had (linked in post #11) was actually the reason why I wrote for help here. In that case it was printed on 100gsm uncoated paper and using output profile based on default uncoated 90gsm. Now I tried to repeat the same steps, but instead of basing it on the 90gsm default profile, I chose the 220gsm uncoated one - and the result is much better. Still though, I think the printer stops at somewhere around 5% of color and then it's just white....
 

pippip

Well-known member
That's a real pity, the machines light screens are just brilliant and really makes a difference on certain jobs, especially for us coming from our old DC242.
 

donster

Active member
UPDATE:

We've been in contact with Xerox guys via telephone and Teamviwer, they checked over how we perform our calibrations (basically we are doing it the right way) and did one sample calibration over Teamviwer. The test print (ALTONA test PDF) did initially look OK. We saved that profile and lived with it for few weeks. On most jobs the results were satisfying, until we came across specific problems. Lets forget the color accuracy now, because the main problem seem to be the details! Or to be more exact - the lack of them.

Just look at the 3 attached files. One is the original data (resized), the other file is scanned print from VP180 and the third file is scanned print from X700 (both scanned on VP180).

If you switch between original file and the print from X700 - you will only notice some color change, which is to be expected. But if you switch between original file and print from VP180, you will notice it's like two totally different pictures. Look at the details in the grass, or in topright corner - there are strange green artefacts/maps on the print from VP180.

I tried printing it out with default profile, changing printer screen mode, changing the DPI from 1200 to 600 - none of that helped. The print from VP180 looks really bad.

I just sent out these pictures to Xerox, so we'll see what they come up with. My guess is - something to do with black channell.
 

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DYP

Well-known member
When you do a Density Uniformity Adjustment, do you or did reset it back to factory defaults before making a new adjustment? After that do a new calibration and and new output profile.

What was the difference in how the output profile was made between the X700 and the VP180?

Are all other color management settings the same?

What happens when you Reset to Default Measurements the calibration for the default output profile after doing a new Density Uniformity Adjustment as I described above? Print your test after that. Then do a re-calibration of the default profile calibration and see what it looks like.
 

donster

Active member
Hmmm, we have not touched Density Uniformity Adjustment at all. I remember being warned to touch it only when it is really needed (ie. we have a page full of orange business cards and the orange is different tint on each edge of the paper), because there is not really a way to reset it to defaults.

The output profile on X700 was created the same way as on VP180, using the same spectrophotometre (ES-1000).
 

DYP

Well-known member
Hmmm, we have not touched Density Uniformity Adjustment at all. I remember being warned to touch it only when it is really needed (ie. we have a page full of orange business cards and the orange is different tint on each edge of the paper), because there is not really a way to reset it to defaults.

The output profile on X700 was created the same way as on VP180, using the same spectrophotometre (ES-1000).

Density Uniformity Adjustment is really needed when you replace drums, 2ndBTR etc. Or, as you say a different tint on each edge of the paper. In your "onboard the printer software" for doing Density Uniformity Adjustment you should have a button to reset it back to factory defaults. After that do your Density Uniformity Adjustment. Until you do that you are wasting your time with all other calibration attempts!
 

Shaare

Well-known member
Hi,

For disclosure I'm a Xerox analyst.

When I setup stocks for a machine, I follow these simple rules to ensure great results.


-1- ENSURE your drums are in good shape! For profiling at least 80% on each. in color quality the base of the pyramid is the quality of your hardware.

0- Create a Custom Paper Settings for everything (I'll explain why later).

1- On anything above 210gsm, run both the density uniformity adjustment and the image transfer adjustment. I only saw the density uniformity tool used once on a bad stock but I run it anyway once at setup, just in case. Unless your drums are almost dead and your belt is equally almost dead, and even then, maybe only on 350gsm, you shouldn't need the density uniformity tool. I saw it used once on a V80, and once on a 3100, on all my customers.

2- As I said, run the image transfer after the density uniformity adjustment to ensure that the stock has the best results on solids. If your humidity/temperature seriously goes out of whack later, run it again if you see a change. It'll help. When humidity goes close to zero, that image transfer tool will help.

3- Create your alignment for the stock 'Tray 6 12x18 Silk 300' and stick to a certain nomenclature of your choice to make them easy to read as your create more over time. Tray 6 and 7 are pretty much interchangeable for alignments so are 1-2-3. They stick, also, FAR longer than any previous machine and they take 2 minutes to makes. Simplest process in the industry.

4- Run at least 25 sheets before calibration, given your drums and everything else is in good shape. You can't calibrate a cold machine it won't give you optimal results. (this may actually be deprecated but its an old habit I'd have to run a fogra strip across first and 25th sheet to ensure this... I'll do that eventually but for now, its an old recommendation to run a few sheets first. Best time? Middle of a shift.

5- If you have iProfiler (ideal) or CPS (buggy, brownish grays) then only use the defaults 90gsm plain /120gsm coated to segregate your stocks based on coating. The profile will take care of everything else. There is no perceivable difference these days if you create a custom calibration set or not for each stock. I sampled delta e and saw under 1 so no visible difference. Its insanity to do it the EFI way with a calibration sets per stock you end up calibrating all the time. I'd only do a custom calset if the white point or texture was vastly different.

6- At that point run your targets and profile your stocks. Then import them and assign them to the paper catalog in Fiery so you don't need to always specify which profile for each stock. Usually on a Versant a profile for uncoated and a couple for gloss will get you through GRACoL compliance for everything. You don't need to go nuts with a profile per stock. You don't need 4000 or 6000 patches either. The 1417 or so standard works just as well. This isn't a linear relationship between number of patches and quality. It tops off around 1500.

7- If you don't have a profiling software nor a spectrophotometer than try to use, over time, the same stocks when you calibrate and calibrate each of those five. If you are using plain paper, put about five sheets over your target when placing it on the glass.

8- The rare times you need a custom calibration sets are usually when your stock has a very different white point or a vastly different texture that's messing up the Fiery. If you do create one, call it 'Custom CalSet xyz' so that in the list you'll remember this ain't a profile. Its a calibration set.


Now a bit of background.

When you calibrate, you are essentially ensuring that at 0%, it ain't dripping. Just like a plumber. You're ensuring that at 0,10,20,30% etc each of those primary colorants outputs the optimal quantity of toner. How do you know what's optimal quantity you ask? Well, you are basing your results off a certain stock, i.e., the Xerox 24lbs plain for example. So they tweak those densities based on a certain stock. How well it looks on a given stock is taken into account. The paper is the N'th colour in any printing system... (TM by me! lol) That's why you have five calibration sets that covers most stocks. Those calibration sets are then tied to profiles. These ICC profiles, be them for a TV or a paper, are basically just a huge lookup table... for that LAB color, do this in CMYK, and so on. Its a two column spreadsheet which, from all those 1500 little squares of different color it scanned, tells the machine how to print colours accurately on this or that paper. Its like a pair of glasses for the machine and a certain paper. The profile also takes into account the white point of the paper. You see, depending if your paper has too much optical brighteners (ie its blueish) or its yellowish, that paper white point is essentially the N'th color in any printing system. It matters. So you can bet that any paper that has a white point close to the reference point of your default calibration set/profile combo will work well given a similar surface. If you never callibrate the 300gsm gloss and you are printing on that then you'll usually find you have a magenta cast btw. Having someone like me do the profile and colour training is usually worth it if you want stellar quality that is repeatable. People that calibrate sporadically on changing papers ensure that they have no consistency over time: the customer comes back a year later and they can't match the proof: they don't remember which particular paper they calibrated on back them and when etc. Try to ensure you stick to your house brands for calibration. Other thing: you don't need to calibrate all the time. Those days are gone. Look, when do you wax your car? Well, you look at your car, and decide right? Same with your printer. Get yourself a quality control document that exposes primary gradients, flesh tones, spot colors etc. and print that once the machine is pristine and calibrated/profiled. Keep it! Then print it again and compare that output before a colour critical job and you'll know if you need to calibrate. Remember, you need to calibrate the calibration sets that is the closest to the stock you'll print on. If you are doing glossy business cards then that's Gloss 300gsm. If you are doing a Cougar 350 then that's either Uncoated 90 (or a custom calset since that stock is hard). A custom ICC profile (not a custom calset) will give you far better definition in highlights and shadows, give you a crisper look and better more accurate color and details. If you reread this post a couple of time and stick to the recommendation you'll find having consistent color is easy.

9 - Use the Paper Catalog in Fiery to assign those profiles! I know I've said this but doing this will save you lots of problems and its far easier to set up job with the Custom Paper Settings integration into the Paper Catalog since you only need to have one dropdown: the paper catalog dropdown.

Okay, my fingers are numb feel free to ask me anything else cheers!
 
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donster

Active member
Wow, thanks for your post. So much information. Will indeed have to re-read it a few times! :) My boss is considering gettings ES-2000 with CPS, so that would move us a bit further.

Anyway, the main problem i mentioned in post #23 (the strange rendition of details, green artefacts etc.) has been fixed! The problem was, that I set rendering intent for RGB->CMYK images to "relative colorimetric". When I changed it to "Photographic", the result is WAY better.
 

donster

Active member
Actually - it was originally in Photographic/Perceptual, but I changed it to Relative colorimetric after seeing these explanations. My thought was, that if I have 2 colors - one is within the destination gamut and the other is outside, I will want only the one color that is outside the gamut, to be moved into it - without touching the other color that was already in the gamut. So in theory, this sounded better to me. Obviously, real life example shows it causes other problems :)
 

MrSchmidt

Member
So I am here with some sort of the same problems on our V180.
I had color management training so I know a little bit of what's going on but for this ongoing problems I have no clue. I also have an es1000 spectophotmeter and no color profile suite. But lets go from how to make a color calibration/ linearisation for a specific paper (we use coated mat from fedrigoni). I had problems with skin tones.
I took some test images from fogra so that I can see the difference between before and after and so it goes. Service guy made an output profile (which i cant) on a paper that he got with him and the tint of the paper was yellowish (with no whitening substrates) and here is the first question. He said we just needed an output profile of what a machine can do/output, and then make a calibration on specific paper (lets say 150g mat Fedrigoni, which has whitening substrates in it and is far more whiteish). We made a print with his untouched output profile (no calibration on my paper) and the skin tones on my whiteish paper where OK. Then he took his es2000 and make a calibration on my paper and the skin tones were worse! (yellow/goldish tint appeared). I did the same (because we wanted to see if this problem was with me making calibration wit ES1000....but output was pretty much the same, worse. So how come an pure output profile with no color calibration is better than with one with it? I cant get color consistency or to say I can only get wrong color consistency when calibrating. Pure Output profile is what a machine can output and it was made on yellowish paper so if I am not mistaken the machine now takes away the 1 or few more % yellow when calibrating on whitish paper and the results should be with less yellow tint NOT more. OMG I cant even understand me....
Hope you at least see where I am going. The service guy should do an output profile on the same paper or at least very similar (white point) paper so that my calibration would work. And even if I take whatever of the output profiles that are on the V180 the yellowish tint is there after I do a calibration. The best results are with pure output profiles...which I cant make and cant control over time.
*And I had the same problems as mentioned in posts here before with dynamic range after I did the calibration as DONSTER did.
 
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DYP

Well-known member
Why are you not making your own profile. That way everything can be done after making sure your machine is setup correctly in regards to drum quality and uniform density. Only then start the Calibration G7 process and then proceed to the profile making on the specific paper you want to use. And be sure to do at least two copies of everything when doing this.
 

MrSchmidt

Member
Why are you not making your own profile. That way everything can be done after making sure your machine is setup correctly in regards to drum quality and uniform density. Only then start the Calibration G7 process and then proceed to the profile making on the specific paper you want to use. And be sure to do at least two copies of everything when doing this.
I dont have a color profile suite to make an output profile. I can only do a new calibration set on on a specific paper i use based on a previously made output profile. Yestraday I had the whole process of reinstalling Fiery since it had so many problems with imposition, paper catalog, VDP free form create files, .... and I can go on and on with bugs it has. So I ordered a reinstall. Hopefully solving also my problems with calibration also but .... we'll see
It is here in forum written I could go through the day with just a few calibrations made on top of the output profile which is the most closest to specific paper (like default 140g silk output profile, new calibration set for a 150g mat coated) and so on. I think this is the right way. But as soon as a make a new calibration set yellow/gold cast appears no mather whatever the profile I take to be based upon. So for now I am using just default ouput profile which is wrong if I wanted color consistency.
thanks again, J
 

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