Hi All,I am a graphic artist and run an offset press. I have noticed an odd problem that has cropped up thrice in the last 150 odd jobs. When a job is RIP'ed by the service bureau I have sometimes noticed a Patchwork (mesh-like) pattern on the Black separation film. The Service bureau is unable to identify the problem in spite of correcting frequencies. The mesh-like pattern only occurs on the Black separation. C,M and Y are not affected no matter what the density. Upon printing, the mesh effect overlays all other colours. I really need some help on this. The SB takes the easy way out blaming it on the software. Other Service Bureaus also give the same result with varying degrees of density of the mesh. I use Corel Draw 11 and X3 along with Photoshop running on Win XP SP-2 on a system with a Core 2 Duo, Intel 975 Mother board with 2 GB RAM and a 1 GB Graphics card. Can someone out there please HELP!!
Please attach a sample Corel file that has done this or e-mail to davidmilisock@graphictechnology.com
Also can you describe the method used to send th efile to the service bureau? PDF, EPS, PS native CorelDRAW file?
The files are sent to the Service Bureau as native Cdr files. The SB rasterises it into EPS and outputs the film. The page where the problem occurred was part of a magazine of 160 pages, all done in Corel X3.
The problem, however occurred only in this one page which had a .PSD file covering most of the page area. However the Mesh pattern is visible even outside the PSD area. I was working on Corel 11 before and have not faced this problem. In previous errors (this is the third time) the pattern occurred (Again in Black only) where TIFF images were placed.
xspillai
Is the PSD or TIFF perhaps a scanned image, from an already printed picture?Is there anything on top of the PSD or TIFF image, like a lens or something?This looks like a typical moiré pattern problem, and I guess there is a conflict between the image and something else, that makes the RIP create these patterns.
The image is a PSD. I agree that it looks like a moire perhaps, I suspect, caused by incorrect screen angles at seperation. Is trher any way to prevent this happening. Can I prepare the screen angles myself? If so How?