Information Needed Process Color on 2-color press print order

[oldfa*t]

In the past 42 yrs I have learned the hard way from trial and error that on a 2 col press, my best shot was cyan and black down first, then come back with red and yellow last, its scary in the beginning, but you always run strong in your first pass, then on last pass you have control over final product, (stronger or lighter) if theres color missing you are sunk!!!!!!
As for press upkeep, always did my own, press needs to be working well

 

[pressing situation]

Good to hear from you, I love all the feedback and tips I get from you guys.
One thing I disagree with you on is the owners don't care. You have to communicate the problems and the parts that need to be changed. A copier has a speck on the output, they call for service.
How did it get to press operators are bad because they cant fix anything that goes wrong with the machine. Need new rollers, your a bad press operator that doesn't know what they are doing.
I got fed up with that. I had to take over running a press dept. recently and first thing off the bat, I told the owner what I need to be fixed. He did it and spent a small amount of money to do so and now his production and quality is up 75% and his waste is down 75% and my stress level has almost been eliminated. He's happy the sales people are happy and the production manager is happy.
I have been there with owners that will not spend a dime to fix a machine, they are foolish because thier profits and the poor soul who has to fight with the equipmet go by the wayside.
O.K. sorry, back to the original question, on a Di there are two towers. Tower one holds black and magenta, tower two holds cyan and yellow. First color down is black, it goes to tower two and lays down cyan, back to unit one, magenta and last tower two is yellow.
I am not an expert and don't claim to be but I have been a printer for 33 years and love to hear from you guys, learn, and teach.

 

[Chris from Printshop]

Old Fa*t, I'll give it a go doing 3c in that order ... I don't think I have done before and it makes a lot of sense, provided the plates are suitably trapped.

In fairness, the chap I know who would always do MY, CK did so but used two proofs for reference; a progressive (just the M&Y) and a full assembly (CMYK). It may just have been a convention he'd picked up over the years ... he's been doing it for over 45 years now (and retirement is looming) but the work he turns out really is second to none. There are some craftsmen you see every so often in life and you think to yourself; "When he retires, there really won't be anyone out there that will be able to do it half as good.".

 

[DanRemaley]

4/color on 2 color press

The correct sequence is K/C then M/Y just like a 4/C press. Actually K can be last but it must be CMY to get the proper overprint colors (RGB). The densities are 1.70K 1.30C 1.40M 1.00Y. More importantly is the midtone dot gain (50%) patch should read 70% on press (for C&M) at the above densities. Black 72% and Yello 68%.
All the images are separated to these numbers in Photoshop. If you can't get these gain numbers, make plate curves or buy a higher pigment load ink.
90% of print problems are "dot" related, 10% solid related, buy a densitometer and measure dot gain. "Google Me" for more information. . .
Any questions call 412.889.7643