CMYK problems with printer's RIP

[kevinmcsherry]

Hi all. I wasn't sure where to post this question, since I can only see an option to post questions for the iPad. Mine is about Designer in OS X. Please move the topic if it's in the wrong place.

I create posters -usually around A1 physical size, they're a mixture of sometimes very complex vector layers (as I convert mono drawings as in the example attached) and raster layers for ageing and texture. They can be around 150 -200MB. I also create them in CMYK since I was told that the colour space has a wider gamut. I have converted to RGB for one large format printer and they've had no problem at all outputting posters.

Now -the problem: I sent these files as CMYK PDFs (reduced in physical size to A3) to a different printer, since that's what they wanted and my files caused all sorts of problems. Crashed the RIP (whatever that is) and generally took aeons to process. I had to cancel the task before I alienated this chap. Anyway, he said that the files weren't flattened -and that there were thousands of vector curves and the RIP couldn't handle them. So my question is -doesn't exporting to a PDF do the flattening anyway? Even after I exported to TIFF and then again to PDF, there were still problems. Can anyone tell me what best practice is for sending to a trade printer who wants CMYK files?

 

Looking forward to hearing from anyone with expertise!

 

Best regards,

Kevin

[toltec]

A software RIP (Raster Interface Processor) converts an image file into film (usually). Basically, a printer driver.

 

Some RIPs are better than others as they are programs and made by different companies. The same way Photo editing programs are made by different companies and some RIPs struggle more than others. So you could try a different printer.

 

If your file is really too complex, with too many nodes or maybe too many gradients it can overwhelm any RIP. A couple of decades ago gradient fills use to cause problems, I can't speak for modern RIPs..

 

The different things you describe are not related. CMYK has nothing to do with curves or flattening.

Outputting to PDF will absolutely not flatten the drawing. 

 

Flattening. In Photo (Document > Flatten) turns multiple layers into one single image layer. Vectors are converted to bitmaps.

 

However, what I suggest you do is

 

1 Convert the document to CMYK. Document > Colour Format > CMYK.

2 Resize the document to A1. Document > Resize Document

If you need bleed (almost certain) make it a few mm bigger all around.

+

This one happens to be A1 landscape.

 

2 ASK THE PRINTER WHAT RESOLUTION IT SHOULD BE. For litho, normally 300 dpi, for a poster, I suspect much less.

3 Export as JPEG in that resolution. The one above is 300 dpi

4 Set the JPEG quality to 85% (see below)

 

What you want is a huge CMYK JPEG. Despite that, the file size should only be a few Megabytes. (Less than 10) It is 9.13MB below.

 

Tell the printer that it is for an A1 poster.

 

He should easily be able to cope with that.

 

 

When you do documents in the future. Start as A1 at 300 dpi and output as I suggested above.

 

You might want to output the text as text (rather than part of the JPEG)

 

Load the huge background CMYK image into Photo and put the text and text frames on top. Export the whole thing as a PDF

 

 

[kevinmcsherry]

Thank you very much Toltec, that's very helpful. In fact, gradient fills were also causing problems in my files when exported to PDF. If there was a curve containing a gradient fill or a transparent gradient, it sometimes wouldn't export that curve. 

 

All the best and thanks again,

 

Kevin