cloudy print with CTP

[pjozsa]

Hi all, we just moved to digital plate making from analogue and experiencing cloudy print problem.
With analogue we did not see this.
It occurs above 50%, we have no problems below.
Please check the attached pics, 200x scan.
It seems there is no proper ink coverage at solid areas.
Where the hell this problem coming from? That bloody oxygen again ??
We exposed a soild(100%) plate just for testing, print is perfect, no cloudy effect.

Plate: Macdermid Digital Rave
Imager: Esko CDI
Ink: UV flexo
Substrate: semi-gloss coated paper

We use tube exposure frame, with new Philips TLK tubes.

 

[pjozsa]

another pic, look around the halo of the letter 'a'.
please note, it is not overpressure!

 

[Dersu]

Hello Pjozsa,

What kind of tape are you using? Have you tried different tape?

 

[shfierce]

Hi Pjozsa,

This is problem of Tape. If you try harder tape on more highlight areas. and soft tape on shadow plates you can have better control on these issues.

Regards,
Salman Anis

 

[pjozsa]

Thank you guys.
We use medium hard foam tampe from TESA.
Could be the tape but I doubt it, because with the same tape and 100% solid plate there is no cloudiness...

 

[shfierce]

Thank you guys.
We use medium hard foam tampe from TESA.
Could be the tape but I doubt it, because with the same tape and 100% solid plate there is no cloudiness...

Hi Pjozsa,

To overcome this issue you have to separate some colors with same kind of screen area on different plates and use different tape for mid tone and shadows. i-e you have to play with saparations may b for some job you have to make 2 plates for one color . one plate contain mid tones and one contain shadows only, then you can use different tapes on one color actually. Hope it will help you.

Regards,
Salman Anis.