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So I had a 600-1200dpi printer but we wanted to get a 300dpi output because we wanted a rougher dots for screenprinting film.

Is there any workarounds or settings I can use to get a 300dpi output from 600dpi printer?

Previous question:

So I had a file which is 300dpi and we had a 600dpi printer. We wanted some parts of this file to remain 300dpi when printed but the rest is 600dpi. The only option this printer has is 600dpi and 1200dpi. How can we get a 300dpi output on 600dpi printer? Is there any tricks to it or a hidden settings mybe?

EDIT : To be clear, out point is we want a more rough dot because we want to use it as a screenprinting film.

So we want some parts of the print to be more rough than others with 300dpi printout and the rest is 600dpi.

  • Now that question can not be answered without knowing the exact technical pipeline and having really deep level control of your system. I mean you could take on the job of the RIP and or drivers. I suppose that is one of those things where the old adage "If you must ask...", but yes its possible but probably not worth the effort. Convert the image to bitmap. – joojaa May 17 '18 at 5:29
  • So I had a 600-1200dpi printer but we wanted to get a 300dpi output because we wanted a rougher dots for screenprinting film. Is there any workarounds or settings I can use to get a 300dpi output from 600dpi printer? – PlanetCloud May 17 '18 at 6:36
  • by the way you don't need to add a link to the old question, GD.SE keeps a history of the edits - there's a link added automatically at the bottom of your question for that. – Luciano May 17 '18 at 6:58
  • @Luciano, owh, thanks! Im new to stackexchange community. – PlanetCloud May 17 '18 at 7:13
  • it would probably be better if you would have asked the question anew and rollback this Q. Anyway i would modify the question to a more answerable form how to make the screen rougher, so making larger LPI is is your goal not changing printers addressing. Because thats what your pretty much aiming for. The later being within realm of possibility but if a client really requested me to do so i would charge a arm and a leg for the service (because its HARD). And most likely they wouldn't know about how screening woks so they would ask me to do what you ask but really mean adjusting the screen. – joojaa May 17 '18 at 7:26
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Based on the new question.

My assumption is that you want to use the printer to screen photographic images.

In my opinion, you are using the wrong approach. Yes, a 300dpi will render a bigger dot and could be helpful in some cases.

If you can do that the printer would have the specific panel to do so. I remember having a really old LaserJet printer that had this specific setup.

But if your printer's driver doesn't have it you probably can not.

But in my opinion you are using the wrong approach.

Convert your images to 1-bit images

The way I would work with 1 ink images is converting them to 1-bit image.

This way you can control the screening type. Either using Halftoning or error diffusion.

In Photoshop:

1) Define the physical size of the image.

2) Convert it to grayscale

3) Convert it to 1 bit image or only "bitmap"

4) Chose the type of screening, halftone or error diffusion.

You need to play with values here to see what is best for the type of silkscreen you are using and the photo itself.

Error difussion

The tricky part is to calculate the resolution of the 1 bit image.

Let's do some math:

Let's think you are using 120 threads per inch silkscreen.

You should do some tests starting with 120 PPI image.

And make some other test images at for example 100, 80 or even 60ppi image.

This, of course, can change if you are using the "jelly film" (which I do not remember how its called) on top of your emulsion.

Here is a sample image to see how changing resolution affects the dot size. In this case, I used 300, 150 and 100 px images (Left column), so the 1-bit image has clear full pixels, not interpolated (right column).

(Open the image in a new tab and see it at 100% size)

enter image description here

Halftonning

In this case you want to use the real PPI equivalent of your printer. If your printer has real 1200x1200dpi use that. If it is 1200x600 dpi, use just 600 PPI on the file.

In this case starting with the same 900px width image (300ppi) I played with different halftone screens, 60, 45 and 30 LPI.

enter image description here

Original Image


I would say that this can work for 1 ink image or for artistic renderings of color images, using for example duotones.

enter image description here

To see how to prepare a duotone, take a look at this.

But for a color selection or full-color image, let the prepress buro handle it.

  • This works, however blending the different screens is a bit tricky. – joojaa May 17 '18 at 18:18
  • This is what we do where I teach, halftone to look like desired LPI in Photoshop and print on a regular high res printer. The difference is we do one file per color, which could probably be a better workflow but works well for novices. – curious May 17 '18 at 18:22
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You do nothing. Your question is most likely result f a erroneous assumption.

A 300 DPI image is not equal to a 300 DPI print. Which is why people have wanted to differentiate and call the images DPI: PPI instead, let us use this nomenclature for the rest of the post. A full color or gray scale 300 PPI image needs something like 120-140 Lines per inch to be able to mix the color because the device mostly needs to have some 10x10 tto 16x16 dots to represent the intermediate colors. So that means that your printer needs around 1200 to 2000 DPI to comfortably output a 300 PPI image.

Now obviously if your "image" is a two color bitmap. that is it only has full black and full wihte with no intermediate color then you also have nothing to do but the above does not really reflect how it works.

The printer will handle this for you.

  • "Which is why people have wanted to differentiate and call the images DPI: PPI instead" Because digital images actually do not have dots, but pixels instead. n_n So please stop using (dpi) in parenthesis, they are not the same. – Rafael May 17 '18 at 1:03
  • Well sortof @Rafael. If it was me i would stop both PPI and DPI and use width as a metric instead of a hard to understand per unit thing. Anyway the problem is that Adobe actually uses DPI for this in OP's version of the software. But still its not so simple a pixel and dot are abstract enough concepts that its not all that clear what to use where. – joojaa May 17 '18 at 4:47
  • Point being that both Dots on printers and pixels on computers exist also in exotic flavours. So while PPI and DPI solves the problem that is a bit like following similie: You could measure inteligence of a group with animals per league, but offcourse by not knowing the animal type its relatively meaningless as a human is more intelligent as far as we know than most animals even in large groups. Same happens here there are dots per inch tgat arent compatible with other dots per inch, but also there are pixels per inch that due to nature of data are not compatible with other pixels pee inch. – joojaa May 17 '18 at 5:01
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    To be clear, out point is we want a more rough dot because we want to use it as a screenprinting film. So we want some parts of the print to be more rough than others with 300dpi printout and the rest is 600dpi. Sorry for the missconception before. PS : I am not a native english speaker so I apologize for grammar mistakes and missconception. – PlanetCloud May 17 '18 at 5:19
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End use printers can't target a specific area and change the dot frequency for only that area. It's "all or nothing".

Think of it like baking a dozen cookies. You can't tell your oven to bake 9 of them at 350° and 3 of them at 250°. That's simply not how it works.

If you want artwork to appear differently then it's the artwork which must change, not your printer settings.


After the question update.....

No. You can't alter the physical capabilities of your printer on the fly. The dot frequencies are set by the manufacturer in the printer firmware and are designed to work with it's onboard computer. Such settings are customarily never user accessible. Once again, if you want the artwork to appear differently, you need to adjust the artwork, not the output device.

  • It's actually not true. If you would share the name and model of the device you want to print on and also RIP or operational software you are using to control the printer, answer would be much easier to get. – mrserge May 17 '18 at 18:44
  • @mrserge It is Konica Minolta Bizhub C224 – PlanetCloud May 18 '18 at 3:42
  • For this particular device you can't do anything as driver do not allow to change resolution: Print: Main; 1,200 dpi × Sub; 1,200 dpi – mrserge May 21 '18 at 13:19

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