printing sequence

ar17

Well-known member
what is the recommended printing sequence for offset packaging? we normally do kmcy; hope to get advise and inputs.

thanks
 

gordo

Well-known member
what is the recommended printing sequence for offset packaging? we normally do kmcy; hope to get advise and inputs.

thanks
The standard offset ink sequence (the one that industry standard ICC profiles reflect) is KCMY. So if your proofer is set up to proof to an industry standard then that is the sequence you should run otherwise you will be creating unnecessary difficulties for yourself.
 
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turbotom1052

Well-known member
Does your company try to print everything with cmyk? Do you run PMS colors when it comes to corporate color matches? If your not willing to incur the addition expense of running PMS colors for critical matches my preference for sequence is to run KMCY in most cases. Having a prepress profile set up for this sequence will be the best way to have success with it. By running KMCY it will allow you to print them hard to lay down purple combinations. The purple combinations will lay much smoother with KMCY.
 

gordo

Well-known member
Does your company try to print everything with cmyk? Do you run PMS colors when it comes to corporate color matches? If your not willing to incur the addition expense of running PMS colors for critical matches my preference for sequence is to run KMCY in most cases. Having a prepress profile set up for this sequence will be the best way to have success with it. By running KMCY it will allow you to print them hard to lay down purple combinations. The purple combinations will lay much smoother with KMCY.
Technically you can run whatever ink sequence you want to. Just keep in mind that if you run anything other than KCMY you will no longer be running the same ink sequence that industry standard specifications were run at. Your gamut will be distorted relative to the industry norm - and that may have negative consequences depending on your customer expectations.
 

aqazi81

Well-known member
I always ran KCMY but on some jobs it can be changed according to coverage of a particular ink.
On 2 Color presses I've used C+M and K+Y , C+Y and K+M.
 

arossetti

Well-known member
Does switching C and M mess with your trapping? Do you need a different inkset from your vendor specifically for KMCY?
 

turbotom1052

Well-known member
I've found that with most sheetfed ink sets, the cyan and magenta are interchangeable without the need for any tack adjustments.
 

ar17

Well-known member
i am set to re-profile the press; and will i get different results by using kcmy and kmcy? another thing, what is the standard screen ruling for packaging printing and the best dot angles for cmyk? thanks for all the inputs....
 

gordo

Well-known member
i am set to re-profile the press; and will i get different results by using kcmy and kmcy? another thing, what is the standard screen ruling for packaging printing and the best dot angles for cmyk? thanks for all the inputs....
You should get different results since the CM, CY, and MY overprints will be different. There is no standard screen ruling specific for offset packaging. There's quite a bit of FM screening used in that market (especially if extended gamut printing is used). But if you stay with AM then use the "Round Dot" (round through the tone scale) i.e. non-transforming/non-Euclidean dot shape/non-composed.

The Standard 4/C U.S. CMYK screen angles are

15, 75, 0, 45

Other CMYK screen angle sets that are usable

15, 45, 0, 75
15, 75, 0, 45
15, 45, 30, 45
45, 15, 0, 75
45, 75, 0, 15
75, 15, 0, 45
75, 45, 0, 15
75, 15, 60, 45
 

turbotom1052

Well-known member
Technically you can run whatever ink sequence you want to. Just keep in mind that if you run anything other than KCMY you will no longer be running the same ink sequence that industry standard specifications were run at. Your gamut will be distorted relative to the industry norm - and that may have negative consequences depending on your customer expectations.
Gordo,
Id expect nothing less than your response from a pre press guy. The human standard for pro creation involves sexual intercourse. There are at times that couples must resign themselves to other methods. Such a deviation from the standard would not be my first choice, but can be for some, their only hope. I offered a work around that has proven at times to be effective. It may not be as fun as kcmy but it can get the job done.
 
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danremaley

Well-known member
The "correct" color sequence after testing by PIRA and others is K-C-M-Y or C-M-Y-K (Black can be first or last). The reason PIRA explained is that the 'Red' (color) trap is better with M-Y together, and humans are very sensitive to the color Red. If you put C-Y together then the 'Green' would appear better BUT the Red is horrible! . . .
Dan
 

gordo

Well-known member
The "correct" color sequence after testing by PIRA and others is K-C-M-Y or C-M-Y-K (Black can be first or last). The reason PIRA explained is that the 'Red' (color) trap is better with M-Y together, and humans are very sensitive to the color Red. If you put C-Y together then the 'Green' would appear better BUT the Red is horrible! . . .
Dan
Mnnnnnn...I don't think so.

1. I guess it depends on what you mean by being very sensitive to the color Red. Human vision is most sensitive to variations in Green - not Red. This is an evolutionary bias. You can google for more info and the science and biology on this fact of human vision. However, under typical incandescent lighting (biased to Red/Orange) vs the fluorescent lights used in viewing booths, the presswork will skew to being reddish. One reason why a 3/C neutral grey in the color bar often takes on a Reddish cast under home lighting.
2. Yes, Black can be first or last in sequence. Since it is an achromatic color its position in the sequence does not affect color. However the amount of ink coverage can be a determining factor as to whether Black is first or last down. In a traditional UCR separation the Black printer (the skeleton or Key ink) goes down first since it carries less ink than C, M, or, Y, hence the C,M,&, Y inks will have more uninked paper to trap to. One could argue that with the GCR, and especially heavy GCR, separations used today K first down may not be optimal due to K's heavy ink coverage. In newspaper work it's not unusual to see a YCMK ink sequence because in a traditional separation Y has the greatest ink coverage and hence helps to seal the absorbent paper so that the following inks trap better.
3. For the best trap it is preferable to separate the inks that will be over printed by as many units as possible since that gives the previous down ink a chance to dry for a more efficient wet trap to the ink that's next down. That separation is why the Green wet trap value (C miss a unit Y) is higher than Blue (CM) or Red (MY).
 

RJ Litho

Well-known member
We have found when we switch M C when the Cyan is solid and the red is a screen it traps best but the hue can become a bit of an issue. On certain board or paper ,trap with these two colours can be an issue We have on moved the cyan down last giving it some time before trapping.Back trap mottle is the culprit on most boards .If Uv is available this can eliminate this trap issue when there is the ability to cure the first colour .We have had success when there is no other option .

RJ
 

gordo

Well-known member
Gordo,
Id expect nothing less than your response from a pre press guy. The human standard for pro creation involves sexual intercourse. There are at times that couples must resign themselves to other methods. Such a deviation from the standard would not be my first choice, but can be for some, their only hope. I offered a work around that has proven at times to be effective. It may not be as fun as kcmy but it can get the job done.
I don't consider myself a prepress guy. I don't think you're disagreeing with what I wrote. If you have to change ink sequence to get the job out of the pressroom - that's what you've got to do. But then you need to find out why and correct the cause.
 

RJ Litho

Well-known member
One of the largest issue not mentioned here is the quality of board, paper is not to bad but board from batch to batch you never know .We have an internal process heavy coverage blue purple color always goes MAG CYAN .We have a73" press and the poor quality of trap really shows its face because of the shear size of the press .We have good success with this process and all press crews follow this process so we can match relatively close on each press .

RJ
 

turbotom1052

Well-known member
One of the largest issue not mentioned here is the quality of board, paper is not to bad but board from batch to batch you never know .We have an internal process heavy coverage blue purple color always goes MAG CYAN .We have a73" press and the poor quality of trap really shows its face because of the shear size of the press .We have good success with this process and all press crews follow this process so we can match relatively close on each press .

RJ
I fully agree that the quality of the stock is the usual reason why color sequence at times needs to deviate from the industry standard KCMY. When it becomes apparent that a companies business model these days, is often built around purchasing sub par substrates, it makes perfect sense to default to a sequence that works under them less than optimum conditions. It is possible to fine tune KMCY to give best results under these circumstances.
 

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