Checking the halftone screen dots shape


Good day there,

I am a new member on "Printplanet" and I am glad to notice how helpful it is,

Okay now my little problem, I have a bag printed a long time ago, I still have a sample and the company decided to reprint the item but we had a problem with the background color being lighter than the sample and the guy at the printing house told me that they had to make new plates/films to proceed into printing. So I thought it could be the halftone screen dots changed since i did not create the old file.

I just need to know how i can check whether my dots are rounded/square/elliptical on Illustrator/Corel/PDF/Photoshop,

I am sorry for my technical words, but It is the first time I go for an online assistance concerning this field :)

Any help would be much appreciated,

Best regards,



Well-known member
Unless you are providing a pre-screened file (and it doesn't sound like it - you'd know if you were), then the dot shapes are determined by the prepress operator and the RIP when plates are generated. While it is possible to set these in some programs, the vendor's RIP would have to be set to override its own settings which would be a rarity.

You should be able to look at the printed samples with a loupe and see what the dot shapes are, but I kind of doubt that the problem lies there. There are many places along the production path where the problem could occur.

The first thing I would check would be the actual color values in your new file versus the actual color values in the old file. If they match, then it could be in the linescreen, dot shape, x-curves, or plate processing (all under prepress's control at print shop). If all that checks out, it could be sloppy presswork, different substrate, or some other press-related problem.


Well-known member

You're going to get a lot of theories on what could be the culprit in this instance. DCurry pretty much listed them all and I also agree that the dot shape is probably the least of them. The only way we could truly help you is if we had the old and the new in front of us to compare.

Do you know how the new plates were created? From an old file to new films to new plates or just old films to new plates or were they made via computer to plate?



Active member
there are many factors affecting the screen background. if the original file is set to a certain percentage and the output device is in prim shape any shape screen will render it to the right percentage. if it is direct to plate the crisper it will be which will make it even more lighter. good luck to your quest.

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