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How do I determine the line screen frequency of a file created in InDesign before submitting to printers?
I am creating a half-page ad for a magazine in InDesign CS6 (also using images manipulated in Photoshop). The printers have specified that they accept “halftones and color up to 150 line screen.” What does this mean? I’ve only done full-color CMYK ads before so I’m not sure what I must do in InDesign and Photoshop to make the ad conform to this specification. Is there a color profile I need to select? Or must I select a certain setting when exporting the file as a PDF (or other format)?
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2 Replies
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This is a weird instruction for the 21st Century.
Such a specification belongs to the days when you would supply a printer with filmwork for them to create the plates from. It’s been nigh on 20 years since I’ve supplied anything but digital files to a printer.Line screen — also known as screen ruling — is a measure of the ‘resolution’ of the printed piece. It’s a measure of lines-per-inch, which translates to the number of dots per inch on the printed page — the more dots you can print in an inch, the finer the image appears. 150LPI is now fairly typical for standard offset printing, it used to be 133LPI. Newspapers use a screen ruling more like 75-85LPI — thats why the images look rougher — fewer dots per inch = larger dots.
SO … color profile is irrelevant to this specification.
The general rule is that the resolution of the digital files should be double the screen ruling being printed at. So, as long as your digital files are 300ppi, you’ll fall within this printer’s dodgy spec.
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Thank you for the helpful response! I sensed that this had something to do with a printing method before my time…lol. I have ensured that the file is 300dpi.
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