Color Management For Digital Press

[tommrz]

Hello All-
I am NEW to color management so forgive me if I ask odd questions. First let me explain my situation. I work for a flexo label printer who has recently installed a Xeikon 3300 digital press. We have decided on taking the route of pushing our digital press into the flexo press color space. Keep in mind that 95% of our work is PMS. We print mostly prime labels. The press is in and up and running. We are now moving on to color management. We have Monaco Profiler along with Color Port and I am using ProfileMakers Color Picker to calculate the cmyk builds for pms colors. So far we have profiled around 12 stocks each with a profile for lamination and UV Varnish. So 24 targets total, more or less. We have 4 flexo profiles we are using to push the Xeikon profiles to using Device Link. These "emulation profiles" were taken from our flexo presses and here again we have 2 for paper stocks and 2 for clear stocks depending on the coating. We have yet to do any real testing on this and I am not sure how solid our profiles are and what type of results to expect. I think our main problem is going to be our clear stocks. We have already noticed some density issues on the IT8 targets we are getting from the press. Also, some of our clear stocks have a craft paper liner and some have a white paper liner and some have a clear liner. I am not sure if or how this is skewing the targets when scanned.
If any of you experienced folks out there could take a look at the above and give me any suggestions it would be greatly appreciated.
I guess I am just looking for some feedback for now. I have read through many threads on this forum and it looks like you guys know what you are doing.
Sorry about writing a book here...
Tom

 

[TerryWyse]

What spectro are you using to measure your profiling targets?

Terry

 

[tommrz]

We purchased a DensiEye 100 with the press. We were told that this device has the accuracy needed for measuring the toners that the press uses. We use a 500 series out in the pressroom but were told it could not properly read the toners. The DensiEye was custom made by xrite and is polarized.

 

[TerryWyse]

The DensiEye 100 is not a spectrophotometer and could not have been used to measure your profiling targets.

I'm not sure what there would be about the 500 series that would make it unsuitable for measuring digital press toners. I could MAYBE believe a specific density "Status" (T or E) may not have optimal filter/spectral bandwidths for the toners but that could easily be resolved on a 500 series or an XRite SpectroEye by using "Spectral Density" where the instrument will target the spectral peaks and thus give the optimal density "sensitivity" for the toners. The fact that the DensiEye 100 is fitted with a polarization filter may indicate the "problem" with the XRite 500 has more to do gloss differential (or whatever) with the toners. If that's the case, they should've recommended fitting the 500 with a polarization filter rather than selling you an instrument that, at least on the surface (no pun intended), is perhaps less capable than the either an XRite 500 series or SpectroEye.

Terry

 

[tommrz]

You are correct, I misunderstood. We used a i1iSis for the reading of the targets. The DensiEye was provided to us by Xeikon to specifically measure the toner densities on our clear stocks because the presses internal densitometer could not. The idea is the press will correct itself and keep the densities consistent using an internal densitometer along with density strips that print on the side of the web. We will have to use the DensiEye "off line" to make those measurements on our clear substrates. There was some discussion about fitting our 500 with a filter but since the press was developed and tested using the DensiEye and it was provided to us we decided to stick with that.
So, we used ColorPort to generate an IT873 target and ran that out to our several stocks. We also ran the same target on our flexo presses. We the scanned them into ColorPort using the i1iSis. I used the ICC from the flexo press and the ICC from the Xeikon to generate a Device Link to push the digital press into the flexo color space.
Does this make any sense...
Tom

 

[TerryWyse]

Yes, this makes sense now.

At least from the information you've given, it appears you're doing all the right things. Of course, the "devil is in the details" when it comes to best practices for press profiling and building good device links. Profiling of clear media can be a crap shoot. With the iSis, you will obviously have to attach the clear media to some sort of white backing before sending it through the device. Remove any other backing material that doesn't represent how it will be seen visually.

There's plenty of "nuance" that can go into device links as well. I don't know what device link profile software you're using (hopefully NOT Monaco Profiler...good (great) ICC profiles, not-so-good device links) but I would resist the urge to enable a lot of the "purity" or ink preservation options. The more you enable ink purity options, the LESS accurate the device link will be (you're compromising the DVL's ability to properly color manage the conversion). I would probably stick with keeping the CMYK primaries pure but allowing the rest to be fully color-managed.

Again, difficult to know if you're taking all the right steps but on the surface it sounds like you're on the right track.

Regards,
Terry

 

[Correct Color]

Are you printing your clear stocks to be backlit, or not, and if not, are you printing white behind your images?

If you're printing white behind your images, best way to get a reasonably accurate set of patches would be to print the same white behind the patches--maybe even double bump it--and then run the result through your isis.

If you're wanting a backlit end product, you'll never get all that great of a result out of the isis. You'll need a transmissive spectrophotometer.

(Edited to add: D'oh. That machine of course can't print white. So n'mind that part. However depending on how you intend to use your images printed on clear will determine how happy you are with your results with the isis. Remember that it reflects light off the patches to take its readings. The more you use your final products in such a way as they are viewed with their illumination reflected off them, the more you'll be happy with the result. The more they are viewed with their illumination transmitted through them, the less so, and the more you'll need to a transmissive spectro to get a superior result.)


Mike Adams
Correct Color