Cyan Mottling when printing before magenta help

[kwikford]

Hello, we are running TKS 6000's and have run into a problem of potential mottling. Our color sequence is C-M-Y-K and lately the cyan looks washed out and grainy when we are running a screened two color overlay consisting of cyan and magenta. We are thinking it might be back trap mottling and will be doing a test here soon but I had one question. With back trap mottling would you have your cyan ink train looking contaminated with fine dust? We have set the rollers, changed blankets and nothing has changed, checked conductivity,etc. Any help is appreciated.

thank you

[Kaoticor]

I am probably not understanding your question right... You say when the cyan is printed over a Magenta image, it looks washed out and grainy. But didn't you say that you are printing cyan first?

[kwikford]

I rewrote my original post but when we run a screened overlay of cyan and magenta, the cyan looks terrible. The cyan plates have a fine dust like appearance and the cyan ink train looks grainy. Sorry about the confusion, wrote the post before I had my coffee.

[gordo]

I rewrote my original post but when we run a screened overlay of cyan and magenta, the cyan looks terrible. The cyan plates have a fine dust like appearance and the cyan ink train looks grainy. Sorry about the confusion, wrote the post before I had my coffee.

It's still not clear. Your ink sequence is CMYK yes?
So magenta prints on top of cyan.
Is the cyan by itself looking terrible?
What does magenta have to do with the cyan problem? Is the magenta printing on top of cyan making the cyan look terrible?

best, gordo

[kwikford]

It's still not clear. Your ink sequence is CMYK yes?
So magenta prints on top of cyan.
Is the cyan by itself looking terrible?
What does magenta have to do with the cyan problem? Is the magenta printing on top of cyan making the cyan look terrible?

best, gordo

The best way I can describe this is when we run a deep purple ad, the cyan looks like it is washed out. Turning down the water helps a little but not enough. The cyan ink train looks dusty. thanks, John

[J]

Originally Posted by gordo
It's still not clear. Your ink sequence is CMYK yes?
So magenta prints on top of cyan.
Is the cyan by itself looking terrible?
What does magenta have to do with the cyan problem? Is the magenta printing on top of cyan making the cyan look terrible?

best, gordo

The best way I can describe this is when we run a deep purple ad, the cyan looks like it is washed out. Turning down the water helps a little but not enough. The cyan ink train looks dusty. thanks, John

If you're hoping for some help, why don't you simply start by answering the questions you've been asked?

J

[kwikford]

Originally Posted by gordo
It's still not clear. Your ink sequence is CMYK yes?
So magenta prints on top of cyan.
Is the cyan by itself looking terrible?
What does magenta have to do with the cyan problem? Is the magenta printing on top of cyan making the cyan look terrible?



J - good point. here we go:

Our sequence is CMYK so yes the magenta prints on top of the cyan. The cyan by itself looks good but looks bad when the magenta is printed on top of the cyan. Any help is appreciated. thank you

[Cornishpastythighs]

Here's a link for you Kwik
http://www.fpc.fi/uploads/files/Mott...fed_offset.pdf

[kbarz]

kwikford,, this must be a wet trap problem,,are your inks uni tack, or progressive, if progressive you can try to reduce tack in magenta,,or if you are trying to put a magenta solid on top of cyan screen this my not trap well, so try changing your rotation to m,c,y,k.. and back trap mottle dosent leave dust in rollors.. also you may want to tell your manager that it may be best to test first then put money job on press.. please let us know what you find kbarz

[kwikford]

Here's a link for you Kwik
http://www.fpc.fi/uploads/files/Mott...fed_offset.pdf

cornish, thanks for the link. I have read up on different web pages regarding mottling and we are going to run a test with just the cyan running to see if it looks better than with running the magenta with it. I'll let you know what we find. thanks for the input