Correct ink rotation on web press

We have a Harris M110 with an end of press UV Curing Unit.

The press can sheet as well as fold in-line.

Images appear dull and lifeless especially in mid-3/4 tones.

Our current ink rotation is Cyan, Magenta, Yellow and Black. All presses (sheet-fed and web) I have produced work on in my 20+ year career has been Black, Cyan, Magenta and Yellow.

I am getting conflicting information from various sources - some believe CMYK is correct, others believe KCMY is correct.

I need some real press experts (pressmen and foremen) that really know what is best.

We run sell sheets, catalogs, postcards on 60, 70, 80# Gloss Book (#2 & #3 grade), .9pt. C-2/S, 32# Hi-Brite as well.

Your help is greatly appreciated.

 

I ran a Harris heat set web for 25 years and ran KCMY. the only thing we tried was uniform tack ink, most often graded tack worked best.

 

I have been on multiple different web heat set presses (G14's, G25's, M1000, M3000) and we've always ran KCMY as well.

 

Hi, I have probably the solution for you problem.
We are using UV color only in our webpress witch is a single tower press - 9 towers in total (One tower/unit for each color). When the press was new in 95` we startet with the most commond setup CMYK, but since we print wet in wet (drying at the end) we experienced that the yellow unit was poluted from the CM color unit after just some few productions. The yellow color went orange or green and infected the print of course. The highlights disaperd and the midtones awfull. Because of this we changed the setup to YCMK. Remark that our yellow color is specially made for this and is marked with "first unit". With this setup we clean our rollers only once a year, just for control. After our change in the setup we never experince troble with polution.

Our current ink is deliverd by Sun Chemicals, English company.
Our print was ISO sertified 12647-2 summer 2010 (99% correct) the reamining 1% where coused by a 0,5% to high dot gain i black unit.

Dont forget the dot gain curve. 40% patch should contain a 20-22% dot gain and 80% should contain around 12-14% dot gain. The rest you
have to work out because I dont have them in front of me at the moment.
By the way I can recomend a calibration software from Bodoni. PressSign. This have been very usefull in this process. It tells you what is wrong and what you have to modify. Density, dotgain, trapping, overprint LAB and much more!! (I am not selling this, just recomending it)
http://www.presssign.com/product_info.php?products_id=54

Best regard

Morten

 

I have used KCMY , the way the ink layes down depends on how much water is used to print clean, less water equals more shine on all presses, there are alot of operators that will not turn down the water because they are scared of summing, time to do a press evalution, that will test the operators too. Too much etch will cause flat looking print too. Remember there are no problems, only solutions.

 

I have 20+ years experience with heat-set at a commercial mag/cat company (we ran K,C,M,Y) and now have 5+ years at a newspaper (we run C,M,Y,K) that does a little commercial work, but it is all wet on wet.
However, I have been into a very clean UV commercial shop whose work looked very good. The printing was better than wet on wet, but not quite as good as heat set. The most noticeable difference between UV print and heatset to me was the flatness of the images. The owner of the company explained to me that it was the nature of the beast and that improving the print is a work in progress with his ink supplier. He even replaced his brush damening system with a custom computerized spray bar system. This modifcation did improve the smoothness of his UV print, but did not help with the flat appearance.
Note: I have tried a K,C,M,Y sequence here at the newspaper, thinking it would give more depth to our photos. But, they became mottled instead and the flesh tones appeared jaundiced. Our RIP seperates images C,M,Y,K and this is the sequence that gives us the best results.
Good luck!

 

I am currently using Harris heat set web for almost 5 years. Through that year, I've never experienced any problems. I recommend that for you to use.