should metalics run first or last?

[jms]

when you run metalics that are over printing process is it better to put them down first or last. the metalic has to trap with the process, and does it make a difference if the process coverage is heavy or a light 4-color screan. thank you for the help.

 

[Sick HP]

we run the metallic first. I have not seen an issue come up with ether heavy or light coverage and how the metallic ink traps. I have never had to change my trap settings for a spot color of metallic or any PMS color.

 

[gordo]

when you run metalics that are over printing process is it better to put them down first or last. the metalic has to trap with the process, and does it make a difference if the process coverage is heavy or a light 4-color screan. thank you for the help.

You answered your own question in how you asked it.

In my experience, metallic inks, whenever possible, should be last down unless they are specifically formulated to be first down in order to be over-printed (e.g. MetalFX type printing). Note that metallic inks are usually varnish coated and that many printers keep the last press unit available for the varnish. This may then require that the metallic ink be first down even though it won't be over-printed.

best, gordon p

 

[John Arneson]

I always run my metallic ink first down, you will see that the more times you split the ink film the smoother the lay. Since metallic inks being opaque will never truly trap. If one has a trap issue, like a large solid metallic with reversed out type, I run a skip plate on the second unit to split the film once before the trap unit. I have been doing this for years on POLYART a pain but it works quite well.

Hope this helps

 

[pq man]

We always put the metallics down last never a problem.

 

[nhprinter]

We always put the metallic down last. Since it's an opaque ink it hides the trap.

 

[zoran]

This is a fight we have internally, prepress wants metallics down last as everything is pretty much designed that way, also it makes logical sense to hide traps with opaque (metallic) ink and it forms the shape.
Our pressman, however will rather die than put metallic last and call us crazy. They want metallic first, period.
They always pull up the quote "peanut butter and jelly".

I am glad to see that there are metallics run as last successfully, I guess it all depends on ink formulation and tack.

 

[gordo]

This is a fight we have internally, prepress wants metallics down last as everything is pretty much designed that way, also it makes logical sense to hide traps with opaque (metallic) ink and it forms the shape.
Our pressman, however will rather die than put metallic last and call us crazy. They want metallic first, period.
They always pull up the quote "peanut butter and jelly".

I am glad to see that there are metallics run as last successfully, I guess it all depends on ink formulation and tack.

IMHO, normally your press people would be correct. The rule for ink sequence is dark to light (KCMY) and opaque to transparent (again KCMY). And typically a (Pantone) spot color goes down first.

But metallic silver is a bit different because of its very opaque quality and the leafing of the flakes that give it the metallic luster. Normally other inks will not trap well on top of silver. That's why, for example, you have to use a special "receiving" silver if you want to do process metallic printing like Color-Logic's system. So, in a SKCMY sequence, if you were to spread a process color into the metallic to trap it you the trap might look like an outline around the graphic. However, if the sequence is KCMYS then the art would be spread under and the trap be covered the opaque silver - so you wouldn't see it. (Some printers butt fit graphics to silver and don't trap it but rely on the slight spreading of the silver to act as a trap.

best, gordo

 

[blazini]

Really it depends on many things and it needs to be a collective decision and sometimes it's trial and error, but you should never rule out the operators opinion if he's run alot of metallics.

You mentioned "overprinting" as if the solid metallic image isn't knocked out, that's usually a problem and if you can't fix it in prep it can be alot of fun on press. How big of a problem depends on what paper you're using (you'll get away with alot more on uncoated paper than anything matte or gloss), whether it's a light screen or solid image that's printing over or under it, run length and the consumables.

The company I work for knows to avoid surprinting a metallic if possible, they will usually knockout and trap the metallic.

If not surprinting, I will run the metallic last as metallics tend to sensitize the plates that run after it. On coated paper, the metallic will be pulled off the web onto the blankets of the later units, since there's actual metal in the ink it will damage the later plates and they will begin to print wherever the metallic is, offset paper isn't as much of a concern. This depends on run length and the actual inks, some times it's not a problem, but all things being equal, I run it last.

In the unfortunate event that it is surprinting on coated paper and we can't do anything to the customers file, then you have to get creative. As Gordo suggested the print rotation for process I use is KCMY, this is common for opacity but ink tack becomes a concern. Tack should run high to low which follow opacity. I think Gordo touched on this with the "receiving" silver, I don't know that term, but I assume it's a higher tack ink.

I ran a job from hell once, A large gold solid image knocked out for 4c lettering but surprinting black lettering, MICR black and gloss varnish. It was really unique because normally I have to run MICR last due to blanket take-off, but varnish had to run last. I makereadied the job Gold-K-C-M-Y-MICR-Varnish which was the most logical. The gold wouldn't print under standard tack K ink and Prep wouldn't knock out the K trap for the gold (other than to cutback screens). I switched to K-gold-C-M-Y-MICR. Then the Gold was eating up process plates within 30k imps (1,000,000 imp job) and the manager said "you guys will just have to fight threw it". The next shift came in and switched rotation once and couldn't run much of anything. I came in the next night and threw the book out the window. I think I wound up running Hi tackY-K-C- Low tackM-871 gold-MICR-Varnish. I had the K and M screens cutback and pushed the K density through the roof . The idea was to run the K density high enough so that the gold wouldn't even print over it and cutback certain screens to make up for my wacked out rotation and high K density.I had several extra MICR plates made, and just changed them every few hours, changing 1 plate on a Harris is no big deal but 10 takes almost an hour and gets expensive. It worked and didn't look half as bad as the previous tries, but I haven't seen any jobs like that on press since.