Colour sequence on a two-colour press

I recently upgraded from a single colour to a two colour press, both Adast machines. The engineer who installed the machine ran KMYC as the colour sequence. When I ran some old plates that reproduced perfectly on my single colour machine in CMYK sequence, I noticed that Black bold text was overprinted with Cyan and Magenta causing that portion of black to appear faded and showed the outlined of the image that should have been behind.

I solved the problem by adding 1% each of Magenta, Cyan and Yellow during the composing process to get a knock out. Is there any other colour sequence I can use to get the best results and retain black as the last colour...or am I just being biased??

 

Try running your colour sequence as cyan & magenta on the 1st pass and yellow and black on the 2nd pass. Running the black last will ensure that your bold text and picture shadow areas will benefit from that sequence.

 

Won't that lead to ink spread in wet-on-wet printing, putting two heavy colours together?

 

Depends on the image i guess.

 

If it's a 2 blanket press it should be fine no matter what the color rotation is. When I ran 4 color work 2 colors at a time I ran the Y and the M first. Then C and K last. There was also less color contamination and tracking. And easy wash up from Y&M to C&K. Depending on the fit and trapping of the job sometimes I run the 2 tightest register colors together. Everyone has their tricks and ways they like best. It depends on the spec's of the job.

 

Thanks, I ran a MY and CK sequence yesterday and it came out just fine. Much more life to the output than KCMY

 

Color sequence can vary from each job. Most of the time we run M,Y and C,K on a two color. Running darker color first also works well C,M and Y,K. We always run Black last on a two color, mainly so you don't run into Y,M,C over printing K.

 

Colour Sequence

Thanks guys. I am back to the tried and trusted CMYK sequence. Have to beware of set up though.

 

I run YM+CK and have no problems with this sequence. Even though with some jobs that have critical color matches one must run to the specific job.

 

When i was printing in two color presses we either started with black and yellow or cyan and yellow. Printing yellow first and then black in the same run never worked except in roland ultras in other presses it didnt work. If there was dark skyes we made sure to print magenta before cyan in the second run. When u print in that order, if u didnt have enough yellow u could mix some yellow in the magenta to save the job ( that was before densitometers weren´t used so much ).

 

Color results aside, wouldn't a KYMC run on a 1 or 2 color press result in longer washes between runs? If so, how does that affect the printer in terms of production time?

 

im thinking that if xpell can run 4/c process in multiple passes then he is not that concerned about production time. kudos to you xpell if you can get a fair enough price for your work to be able to still make money printing like this.

 

Ive tried CY+MK on 2colour MOZ-P and it always works for me, exept when the sheet are not consistently fed from the font lay then tendency to have bold black text image can occure

 

hi

The recommended ink lay down sequence for a two-color press is: first pass CM, second pass: KY.This sequence makes CM inks wet trap which helps align the color result with that of a four-color press

 

When you do a color separation of any design try first to put yor text if it's going to be black in just 100% K if you assign the color on your design as pantone black the pre press will separate that color in cmyk and you will have a hard time trying to register that text specially if it is small

 

i once tried to print yellow-black or yellow-magenta on a 2 color press and got a moire effect.I noticed that every time i printed yellow first it happened all the time.does anyone know why this happens???

 

you just have to find your own color sequence that works for your machine every press is different i run K and C on the first pass and Y and M on the second it all depends on what your coverage is for each color

 

I know a printer who does Y+M and then C+K. He's been a printer for over 40 years. The work he turns out is exceptional. 'nuff said.

 

We run Y+M and then C+K. Speedmaster74 press. Works like a charm for over 30 years.

 

When I run 2-colour presses C-M first then K-Y if you have a densitometer use it, printing on a coated sheet C 1.25 -1.30 M 1.45 Y .95 - 1.00
K 1.60 -1.70 and one thing you have to be aware of is the spray powder, keep it real light, by the time you get to the last past the build up of powder
makes it hard to hold colour Black ink seems to print thought the powder on the last past the best for myself, using "SUN Chemical" inks.