At 600 dpi you would have approx. 10 shades of gray. So you would either have to increase the dpi or decrease the lpi to gain more shades of gray.
This is the formula taken directly from Adobe's print publishing guide.
(dpi / lpi) squared + 1 = # of shades of gray
Hopefully this helps rather than confuses the issue. LOL.
Said another way:
Halftone dots vary in size to suggest grays. You desire a 200 LPI halftone screen ruling. 1/200th inch, center to center.
But your printer only prints dots of a single size. Typical laser printers print 600 printer spots per inch. 1/600th inch, center to center.
Halftone dots are built up from printer spots.
Is a 600 dpi laser printer enough...?
Not even close.
At a halftone ruling of 200 LPI, a 600 SPI printer would have a grid of only 9 (3x3) printer spots out of which to build each halftone dot. So it could only print nine different sizes of halftone dots. In other words, it could only simulate 10 different gray tones--9 levels of gray, plus one for white. For what is considered normal "full range" reproduction of your image, you need to be able to print 256 levels of gray.
So even if your print driver would accept a 200 LPI setting, your print would be horribly posterized.
And that's not all:
I'd like to be able to reproduce the distinctive rosette pattern on one of my collectible playing card.
The printer spots of laser printers are little fuzzy-edged globs of toner powder attracted to the printing drum by static electricity. They are not the comparitively far more sharp-edged shapes that a laser can burn into a photo-sensitive emulsion on a plate or on film. You're not going to get sharply-shaped halftone dots from from a laser printer.
What printer (sub 500$) could help me achieve this kind of resolution ?
Not gonna happen. Not even in the same state, let alone the same ballpark. Fact is, laser printers are very low resolution devices.
Thx for the reply.
I've estimated the lpi by counting the individual rosette I could count on one inch of the picture, is that the right way to do it ?
You say that laser printer are very low res device, could I have better results with inkjets printers ? There are some 4800 dpi devices out there I think.
...could I have better results with inkjets printers ?
No, not given that you are specifically trying to reproduce a 200 LPI halftone rosette. Most inkjet printers nowadays do not print halftones (varying -size dots, consistent frequency); they use stochastic printing (same size dots; varying frequency). It's "FM" screening, rather than halftoning's "AM" screening. An entirely different kind of tone simulation. With stochastic screening, there are no rosettes.
200 lpi is way beyond regular offset printing as well. Only very high-end presses can achieve this quality. See http://desktoppub.about.com/cs/intermediate/a/measure_lpi.htm (random first Google hit) for a more expansive explanation.
Are you sure you are not talking about 200 DPI instead?
I don't really care if you don't believe it. It works.Neither Photoshop nor Illustrator allowed me to specify the lpi I wanted, but CorelDraw does. It works, its the same damn thing as on the card. The Adobe program. I don't see a reason for me to lie about that, but oh well, I did it and I'm happy about it
Please, How did you achieve that? I have a 1200x1200 laser, with a PS driver and I cannot print a rosette pattern... all the prints, despite the high quality, is all smooth... I need to print the same rosette pattern that is in your collectible card... the problem I have is not the lpi or resolution... I cannot print halftones AT ALL... I even tried ghostscript... I tried illustrator and corel, I can change angles, frequencies, etc but my printer just ignores it... I tried changing drivers, getting older versions of the drivers, etc... nothing will print those rosettes... PLEASE, someone help me
Hi! Thank you for your answer!
My printer is an HP Laserjet Enterprise 500 M551DN with a 1200x1200 resolution and Postscript support. If you were able to print the rosettes with a 600x600, I think I should be able to do that too but, I'm a total newbie in that department! Thank you again for your help!
Unfortunately, your printer does not have true postscript. It has postscript emulation which is something totally different. True PS printers have a chip inside them that handles the halftoning. No PS chip, no halftone sadly. I speak from experience. And by the way, the results I got were not so great. I was excited at first because some areas showed really good looking halftones. But overall, the quality was not up to par. So no, I did not succeed with 600 as I first thought. But don't get me wrong, the results were good but far from perfect under a magnifying glass.
Thank you again for your reply
Your printer (Laserjet Pro 200 n251mw) is also with PS emulation, right? I'm asking because I don't need a "perfect" rosette and since my printer have double the resolution, I might get something a little better than you got... maybe. Could you describe the process you used to achieve the "good but far from perfect" results?
Thank you very much for taking the time to answer my questions