CMYK work on Single Colour Press

Hi Guys
I hope you are all well. I recently joined my fathers small printing business to help him out. We have a few well maintained single colour presses eg Heidelberg KOR, Solna 125, Hamada E47np. to name a few. Iv been reluctant to do any Colour work in-house as my operator has over 20 years in the trade, most of his experience is single and spot colour work. I feel id like to experiment a while before considering purchase of a multicolour press. Ive been doing a bit of reading on Dot gain, Solid ink density, etc. Im ready to try my hand at this, but i need a few gaps filled.

Firstly, here is South Africa iv been told we use the European Standards, and the Densitometer iv got is also European Standard. If so, what should my density readings be +/-. Also if im using the KOR for this, what should my print sequence be.

Im sure ill have more questions as i go, but for now thats it. Any help in this regard would be greatly appreciated.

 

oh and iv also invested in 5000 kelvin lighting, just to show you how crazy i am about trying this.

 

i have a QM46-2 Heidelberg and succesflly printed 4 colour work on it. We also rAn to a European standard with our densitometer, my operator works to C- 140, M - 140, Y- 120. As far as sequence goes we were told by Heildeberg to run Black, Blue, Red, Yellow. Hope this will help.
I have just installed a Heidelberg DI 4 Colour press to cut my teeth with 4 colour work in-house and it is worlds apart to trying to work on a single or 2 colour press, i suggest you look around for a 2nd hand press. In South africa You will pick them up for around R700K

 

yes, run k,c,m,y... in some cases you can run y,c,m,k if its giving you trouble... watch the register and make sure your not bouncing the sheets. Be sure to give your operator color bars to measure the densitity at the top/gripper edge of the sheet.

 

thanks guys

I dont think im ready for the DI world yet, but soon i hope. R700k not bad considering to prices iv been qouted here is cape town. Thanks USAPressman.com, iv got colour bar strips to add to the films. Tell me about bouncing the sheet, im not fimiliar with this term.

 

Bouncing the sheet "Watch the registration on the tale" make sure your lay system is set correctly and that your operator keeps a eye on the register. I would run 30 sheets then reload the same 30 sheets to make sure that you registration is perfect. Then when you change colours DO NOT ADJUST the feeder at all to ensure that you will register all 4 colours.

 

Years ago we ran a few 4/0 jobs on our Ryobi 2800 single color. They turned out pretty good. They were
sellable. Just watch your registration s was stated earlier. Run a few sheets then run them back thru. It takes a lot of patients but you can produce good quality 4 color on a single color machine. Good Luck.

 

Be careful of paper stretch too, if you are leaving the job overnight to finish next day wrap it up well.
Alternatively let the stock acclimatise to the print room for 48 hours.
Perfect colour work is achievable on a single colour press, the colour sequences above should be fine but don't be afraid to change them around. the coverage of the job could dictate a change. also don't go too heavy on powder, use the minimum.

 

I´ve never ran 4c on my QM2, because there´s no pull lay. To much circumstances.
But you should have a look at the german machine market, currently lots of well maintained machines are for sale. You can get a DI for as half of R700K.Mostly Heidelberg and Karat. You should have an eye for analog presses too, because of technical problems or lack of plate supply for DI.
Look at: http://www.pressresale.com

 

Cybershafs - what part of SA are you? We also have a QM46-2 that we bought recently. Also want to try the 4c jobs.

 

ive only ever run a single colour press and have done loads of full colour work.
gloss or matt coated not a problem, full colour on a standard stock causes problems as the paper tends to stretch more, and ive always printed cyan - magenta- yellow then black, but use a dense black instead of the process one, to me it looks nicer

 

hi vzd180i. sorry some confusion. i dont have a QM. Im in Cape Town.

 

Cybershafs - Sorry my bad thought about one thing and wrote another

 

Quinton - what grammage sheets do you prefer for F/C jobbing on the QM? and if you say bouncing does this include the middle blowers position to the sheet?

thx

 

hey guys more questions. Only this is about the vintage gretag d142 densitometer im using. ok first thing is that i got a calibration card for it. on it was readings for absolute white and for paper white. I calibrated to absolute white according to the calibration instruction i got. Was this correct or should i have done paper white calibration.

Anyway, here comes the real question. on the densitometer are modes for density and paper. Do i first measure the paper, then press the paper button to read 0.00. and then measure the colour. i feel like im missing something.

 

Its been a long time since I used a gretag, but you dont need to measure the paper each time prior to using it unless you switch paper stock from a gloss to a dull for example. However even if you forget to measure the paper after switching stock, the difference in the density reading wouldnt be all the much anyways.

 

Been a long time since I have printed on a single colour machine, but I used to do cyan, yellow, magenta and black last, purely because it was less time washing up and it only meant taking the dampers out once or at most twice, but I would think you would be using bareback dampers now.
Colour sequence depends greatly on the job you are doing.
Always try to complete the job in the day if possible, otherwise the ink will take a along time to dry and could stretch overnight. I used to add driers to the last colour due to it trying to dry into 3 layers of dry ink

 

It really isn't worth your time. You can farm the job out and make more money. Time is money. You said you want to experiment, but when you buy your multi color press it's going to be a totally different mind set. You'll be stream lining your work with direct to plate. You'll be making ready a 4 color job in less than 30 minutes without all the bells and whistles on the press.

Good Luck,

jtdoonz

 

Same with me. The reason I did that order was because Yellow is quite hard to see what is happening by it's self. ie. hickies, filling in etc. If you have the cyan down first, it makes all the difference. I advise running black last when doing single passes, partly because it is very easy to over do the black. I run large multi-colour presses now days with black down first, but even then I still sometimes run the black on the low side if the picture is rather dark or I want certain details to stand out.

Keep an eye on the green and reds against your proof when doing single passes. Thats the best way of getting an idea how the image is building up.

 

In my opinion sometimes it's even better to print full-colour on a one colour press than on a 4 colour. Because each run has time to dry there is not much blending of process colours. I mostly did C,Y, M, K because starting with C you can detect dampening problems in Y and M as third run makes you able to steer the overall colour. It's very important to check register in the first run. Just pass a few sheet two times through. Adjust density on paper ( uncoated 1.20, 1.00, 1.20, 1.35 coated stock 1.30, 1.10, 1.35, 1.65 is sensible). Don't start with to much spray powder as this shows in later runs. Good luck!