Unwanted image transfer !

[Spectrum Extra]

Hi all

We are looking for any ideas as to why our Black plate ( only ) is turning blue all across the non image areas of the plate .

We are currently using Heidelberg Agfa plates after changing over from Fuji Pro-T 2 . We have experienced this issue with both kinds of plates now and are at a loss as to why this is happening . We have yet to discuss this with the Heidelberg rep as we are only in our first week on the new system and we are certainly open to ideas from anyone who has experienced this problem .

The CMY plates do not fill in blue in their backgrounds but do turn blue where any black image is located ! ?

We are using Heidelberg Saphira CtP fount running at 4% and alcohol running at 10% .

Any ideas and guidance would be greatly appreciated .

Thanks in advance.

Spectrum Extra.

[nhprinter]

I'm just throwing this out there because I've never seen this happen, but my guess is that it's your ink that's causing the problem. In all of the process blacks that I know of there's a little blue in it to make it "blacker". The residue of that could be giving it that blue look.

I'm also surprised how high your alcohol is. It's been 15 years since I've run alcohol, (I'm always amazed how many still are), but when I did...I only ran at 4%.

Hope this is of some help.

Dave

[Alois Senefelder]

Hello Spectrum,

First, are you saying a "Image" of the BLK plate is appearing in the non-image areas of the C-M-Y plates? and this image as a "Blue Cast" ???????


Regards, Alois

[Spectrum Extra]

Hi Alois

Yes , it is a Blue cast .

We are currently experiencing a situation where we are using processless plates ( currently Heidelberg plates but we had the same issue on Fuji Pro-T 2 ) which when put through the gumming unit come out perfectly clean . The issue we are having is that on a print run the black plate will form an overall blue cast on it and on any length of run the black plate image areas will become visible ( as a blue cast ) on the following C M Y plates .

This does cause some issues on longer runs whereby the other colours regularly become contaminated and require replenishing .

Regards

Colin @ Spectrum .