printing advice

[print101]

Yes - I agree with Steveo. Take a look at the proof you are given, and then decide on the sequence.

We are a 80% label shop running 3 CD102's, with a couple of other older presses. We are always changing color sequence to achieve the best results. We dont like running solids upfront, the more impressions the solid go under the more mottled they look. Thats why I said we mostly run from light too heavy coverage.

When we run a heavy combo of cmyk, we find we have better control and better consistency with going from light too heavy coverage. Screens lifting off solids tend to vary throughout the run due to the tack/trapping of the ink. Uncoated stock tend to be more forgiving as the color soaks in. Glossy coated stock we really take the above into consideration.

The inks in conventional offset are all transparent, unless you are printing on coloured stock, and you need to kill the color of the paper, we use a heavy opaque white.

I find color order in multi color printing in one go, like this, going from a 2 color and now printing on a 5 color for the first time, is super imprtant to achieve the best quality print.

 

[wiseguy]

Hi guys! when I used to print on a two colour press we always printed black and yellow first then cyan and magenta. Sometimes it was tempting to take a shortcut and run cyan in the first unit ( much easyer cleaning ) but if there was a blue sky there was a problem. So first increase the tack of the cyan so the sheets almost stuck on the blanket and decreasing the tack of the magenta to the point where you almost had scumming. No improvement swith the color sequence and print the magenta first no problems - but that was those days when you occasionally had to wait for half a day to print the other side of the job. Not to mention removing the ink every day. Now I can´t remember when there was aproblem printing cyan before magenta. But about six or seven years ago we got a batch of yellow that picked up the other inks the tack was too high. No idea to increase the dampening in that case.

 

[Kostagh]

We mostly run web offset. Originally, machines were set to run with Y first and K last. Colors were bland, and unimpressive. Customers displeased. We changed to the classic KCMY (which was no easy task, taking into consideration that ink supply is automatic by barrel pumps) and there was vast improvement! Mind you, we mostly run on newsprint grade paper, 45 gsm. The results were brighter colours and more impressive, more vivid pictures. Also, legibility of the text is vastly improved.

 

[Kostagh]

Some years ago I used to run a 2 color Heidelberg SM for colour works. We even did important jobs such as posters on this machine. I managed to do this without even using a densitometer. I used to ask for digital proofs for the colours I ran in sequence. For instance, if I ran posters for Coca Cola, coke red was the most important so I ran K+C and then M+Y. I had proofs for each colour and for the colour combinations by themselves. It was easier to adjust the machine that way and I must say I had no customer problems for more than 4 years while we ran on that machine. As I have found, the most difficult trick in running 4 colour works on a 2 colour machine is actually WASHING the rollers and inking systems thoroughly enough to prevent contamination. Of course, this lead to rather frequent (as compared to a 4 colour machine) replacements of rollers, large amounts of washing cloth, large amounts of washing fluids and all sorts of cleaning and washing paste.

 

[The Heidelberg Guy]

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.

When I started in offset, yellow (of 4/CP) was opaque, and of course had to be 1st down. I also recall magenta was at one time too maybe, but cant be sure.

 

[steveo]

Well we must have started about the same time cause I can vaugley remember that the yellow was run 1st down and was opaque ....that was probably early 70s?? lol , Im ancient!!

When I started in offset, yellow (of 4/CP) was opaque, and of course had to be 1st down. I also recall magenta was at one time too maybe, but cant be sure.

 

[NZ Printer]

KCMY here - ocassionally switch Cyan and Magenta for trapping purposes ( Magenta screen / Cyan solid )

 

[lildaddy50]

Not a gooner is correct. Blk and yellow fist pass. The reason is not really trap related though since you are going to dry trap the second pass. the reason we did it like this was for more color option. Dealing with Cyan /mag on the second pass we could steer the color in the right direction even if we had run too much yellow on the 1st pass.

Rod (old school)