printing advice

Hi all. I am currently running a speedmaster 52-2 which is being replaced with a sm52-5 in 3 weeks time. When running colour work i always print cyan, magenta. Followed by yellow and black. I have always found this the best way. I have noticed when viewing many machines, that most printers run black on the first unit. Can you please tell me what colours you run on what unit in order, and why. Or is it not relevant as it is in one pass? Regards, Tom

 

The order of printing 4 colors in separate passes is largely a personal preference issue, I nearly always went K+Y on the first pass and M+C on second pass on a 2 color press. When printing process work on a 4 color press, the normal sequence is K 1st then C - M -Y, mainly because there is less chance of the darker colors contaminating the lighter ones, plus nearly all ink manufacturers formulate process inks with the tack reduced accordingly.

You can and I have run yellow down first if you use a high enough tack ink, we did this for instance if your black has a particularly heavy coverage and you like to run it last.

Others may have a different opinion however.

HTH

 

K M C Y is our preferred choice. I find you get better 'reflexy' blues without the warmth caused by laying the magenta over the cyan.

Occasionally we may run black last if there's a chance that spray powder would affect flat tints of grey (made from black only).

If the material allows ie if it's uncoated you can generally get away with any sequence...but on coated art the previous poster has nailed it insofaras the inks are tack graded so that, in the 'correct' sequence, they will 'lift' or print successfully on one another wet-on-wet.

I take my hat off to anyone running 4 colour work on anything less than a 4 col press - there's nothing so depressing as having run the first 2 colours and then realising as you're making ready on the next two that you didn't run enough cyan or magenta

 

That's the EXACT reason why I ran M and C last, Black you can forget about as far as color matching is concerned so the only color I had to worry about was Yellow, of which I took densitometer readings throughout the run


Of course there are register concerns with running separate passes but that's a whole other thread

 

I run KMCY on my 4-col Lithrone

 

Thanks to this forum I've begun running KMCY instead of KCMY and the way the ink lays down is vastly improved, especially on jobs with big cyan and magenta screens.

 

Its all about INK TRAPPing. Usualy cyan is better recive for magenta and Yellow canT recive any colour above it. For single colour the method that used is dry on wet and for multi colour press they usualy go for wet on wet.

 

KCMY. Either way these days with transparent based inks. Used to print 4cp on a 2c Komori if the 4c was down. Always start with the black and cyan in my opinion. Easier to warm the piece up on the second pass. Make sure you are registering HAIRLINE when printing like this or you gonna have a messy looking job. Been KCMY since process switched from opaque base to transparent. You hear of people putting them backwards but that's usually from them backtrapping on their yellow. "Not running enough"

 

1st pressman on 7 c man roland 300, i cannot run the cyan down before the magenta. if the magenta has a screen gradation and i try to put the cyan down first,, kiss the screen bye,bye. its the trap in our very sad ink that we use in our shop. so i use kmcy dont have to worry about screens lost in wet trap inline 4cp+3cc+coating

 

What other kind of process inks are there? I thought opaque inks were only used in 3 col process letterpress prior to the 70's.

But I'm prepared to be corrected

 

I have run 4 col process on letterpress on a Heidelberg SBD and they were transparent inks

Process work with opaque inks?

How does that work?

 

Can someone corroborate what my alcohol pickled brain can barely remember from my apprenticeship days?

When I posted it I wasn't 100% sure on the opacity issue but certain on the 3 colour process.

 

I already corroborated Richard, it was always 4 cols in my shop

 

When you say "kiss the screen bye-bye," what does it start to look like?

 

If I understand correctly...you are now running a 5 color.

In this case - Always look at the image you want to print. We have a set rule that we run from smallest ink coverage to largest. Most of the time its black type, so we run that first, we then look at the plates and determine the larger coverage between C and M. Our yelo is always last. The only time we run yelo forward in the sequence is when there is a heavy solid image that could dirty the yelo.

When running solids vs screens, always print the screens first, otherwise the screen wont lift off the solid and you will have a "fuzzy/reticulated" result.

Good Luck

 

First off, I can print anything without my yellow getting contaminated. Your yellow should NEVER EVER EVER get dirty unless you try and print it too light causing the ink to somewhat "dry" on your blanket, increasing the tack and therefore pulling any color on the sheet preceding it up into the ink train. The only time I might notice some contamination on the edges of the fountain is due to dirty imp. cylinders and possibly some metetering back trapping. the screen-solid thing that print 101 was talking about makes ABSOLUTELY no since. You must have poorly set grippers my friend or you are running a unit way to light to the point of drying on your blankets. Sorry, it's just a fact.

 

In my experience it looks like the red is kind of swimming around on the cyan and black screens - especially on cheap stock.

 

"the screen-solid thing that print 101 was talking about makes ABSOLUTELY no since"

@ Loup....???

Its not grippers or ink drying too fast - its a known fact that if you are printing 4 process colors in one pass on a multicolor press you should always try to print the screen work, of the image, first. Its all about trapping. One color agreeing with the other in terms of coverage. If you run a heavy solid and then a, lets say 50% screen after, you will not achive a good lift off the solid. This happens time and time again when the operator doesnt take this into consideration, sure it will be passable, but you will defenatly see a better result doing it as suggested.

Give it a try next time.....look at the dot and compare?

And by the way....Yellow printed last can get dirty due to ink being transfered from "heavy" solids, my friend...

 

Nonsenese, Print101. Try putting your screens down first on lets say Clasic Crest 100# cover . By the time it goes under impression on the 5th or 6th blanket, with all that squeeze in between, YUCK! You will have the most awful looking screen ever printed or at least that I've seen. Makes NO difference whatsoever where you put a screen on an enamel or silk stock. Now, it does look a little plugged up on your make ready but after 50-100 shts. that problem's overwith. I'm from one of the largest shops in the S.E. U.S.A. and I'm used to any job that could possibly come down the pipe from 8c to 6c with foils and embossing. Screens are only jepordized on offset and opaque stocks. Seeing the red get wavy makes me think, paper fan. What grain was that particular job ran and did you try a change of stock before you swapped units?

 

I think its a matter looking at the job and making a judement call which will work better , if you have heavy cyan/magenta coverage go with magenta first , it helps get that purple the color proofs always show and you never can quite match , sometimes building a percentage of black screen into that C/M combination helps. As far as normal rotation KCMY is SOP but as other have said , black last if you have a solid or a screen you want to keep clean, I was fortunate to have run an 8/c so we could split up the blacks , tint in one unit , solid in the other....like I said its a judgement call after viewing the color proof , but I agree with Richard , kudos to anyone doing 4/c work on a 2/c press

Steve