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I do understand how raster and vector images are rendered onto a 2D surface (screen, paper). Resolution, scaling, etc.

Is it the same inside the machine that makes plates for offset printing?

If so, what is the resolution there? And how does the machine do that? Does it have embedded software that understands all raster and vector formats? Or the image must be pre-rendered on a PC and then fed as pure raster?

  • Note that laser printers, wax printers, inkjet printers, digital copiers, and commercial presses all differ in how an image is transferred from art to print. – Scott Jan 8 at 3:34
  • Sorry, I meant the presses that use plates. – Ilya Vassilevsky Jan 12 at 21:43
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Your question is really too broad - read on and you'll see why, but I'd still like to help you. Look up Computer-to-Plate Platesetters on google for more information. Agfa is a major player in the field.

No. It's not the same as printing on paper. Printing plates are generally made of aluminium (sometimes even plastic), and have a water receptive surface and ink receptive surface to which the ink sticks. This is essential for the lithographic process to work.

There are several different technologies for these platesetters out there, but most use lasers for digital imaging of the plates. There are some which use plastic plates, and some which use metal plates which are then developed/chemically processed to fix the image and prepare the surface for printing. There are even chemical-free solutions these days.

There are too many different brands and technologies out there to mention specifics like resolution, or software used. It would really depend on the machine specs. I suggest you find a machine first, then look up the specs, even contact a dealer, or ask your printer what they use.

  • "Sometimes even plastic" Or even Paper! at least they used to... Back when I was in school... – GoofyMonkey Jan 8 at 14:39
  • @GoofyMonkey Yes, I remember paper litho plates too. They were for very short runs. I used to use them on a Heildelberg TOK small offset press, which had an automatic plate feeder and ejection system. – Billy Kerr Jan 8 at 17:05
  • Thanks! I read about CTP but it doesn't say how the laser is guided along the plate to make the image. I was interested in this part. – Ilya Vassilevsky Jan 12 at 21:44
  • @IlyaVassilevsky think lasers are guided by rotating mirrors in most print technologies that use them. The physical mechanics of this are way beyond my expertise however. – Billy Kerr Jan 15 at 15:53

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