retouching for flexo printing

[andy625]

is there anyone here who has experience of this or know any particularly good resource? as the web seems to be a little thin on this subject.

[Crapaud]

Yep, I've got some experience.

Unless things have changed, there's sod-all on the web about flexo. If I can help, I will.

[andy625]

cool a few things,
I'm particularly interested in dot gain curves, for the purpose of simulating for viewing, and then making a compensation curve. could you just do this by taking the dot gain data and plotting the opposite as a curves adjustment.

also knocking out colours comonly cyan seems to be something thats done quite a lot? any info out the best way to go about mixing the knocked out colour back into the mix, i.e. channel mixing cyan back into the black etc. ?

also back on dot gain curves,
am i right in thinking the dot gain (or perception) caused by the dot gain isn't going to be equal, i.e. say in the mid range where the dot gain is at its largest would a more punchier colour like cyan overpower the likes of yellow? or even print order effect the final cast of the print.

i might have misunderstood somethings, but thanks in advance.

[Crapaud]

Originally Posted by andy625

... cool a few things,
I'm particularly interested in dot gain curves, for the purpose of simulating for viewing, and then making a compensation curve. could you just do this by taking the dot gain data and plotting the opposite as a curves adjustment. ...

Ahh ... dot gain. There's actually quite a bit on the web for this. Google 'dot gain flexo'. This is a reasonable starting point.

By 'simulating for viewing' I presume you mean viewing on screen? I've always worked with unmanaged files - the dot compensation goes in at the RIP. What's your workflow from digi file to print?

Originally Posted by andy625

... also knocking out colours comonly cyan seems to be something thats done quite a lot? any info out the best way to go about mixing the knocked out colour back into the mix, i.e. channel mixing cyan back into the black etc. ? ...

I don't know what you mean by this. A before and after example would help.

Originally Posted by andy625

... also back on dot gain curves,
am i right in thinking the dot gain (or perception) caused by the dot gain isn't going to be equal, i.e. say in the mid range where the dot gain is at its largest would a more punchier colour like cyan overpower the likes of yellow? or even print order effect the final cast of the print.

i might have misunderstood somethings, but thanks in advance.

There are a number of things that'll affect dot gain:the film output / platemaking process / plate material, dot shape / resolution, the press, individual units on the press, the cell size / depth / lpi of the anilox rollers, the substrate, temperature and humidity etc. All this needs to be controlled and monitored for consistant results; change one thing and you may need to change the DG compensation curve.

It'd be worth your while to get technical support in to look at your set-up and advise.