Be careful with references to image resolution vs. output resolution. If I had enough time, I'd research the xerox machine's output resolution. But, to sum up quickly, your laser output could max out at 600dpi; but 1200 is possible. Typical high res platesetter resolution is minimum 2540dpi; typically 5080dpi for offset print production printing image resolutions of 300+ppi. Desktop lasers are not capable of printing offset like output. Other factors like RIP screening, paper, and environment can affect output. I've seen some very impressive waterless offset printing that just cannot be matched by a laser. Your desktop will come close. but unless it can print stochastic @ 5080dpi, you may not be able to achieve the snap you'll get off press. Typically, your image res would be 150ppi for 600 to 1200dpi output. There is no detectable difference between 300 vs. 1200ppi on a laser. I would think that you'd be able to select the maximum resolution for the Xerox in ID's Print dialogues; osually referred to as "High Resolution" with image resolution set for 300ppi.
Your comment is welcome John but like so many others I've read in these forums replying to specific questions, doesn't actually answer that question:
How do you get ID to output at 1200 DPI?
I would also like to make it very clear John, that there really is substancial and detectable difference between 300 dpi and 1200 dpi on a Xerox LED engine "laser printer". Perhaps the old spinning mirror lasers might not be much good at settings over 300 dpi but these new Xerox (C2255) are a far cry from a true laser printer. In specifics... They are not a laser at all. They use LEDs to put the image on the drum/belt. No laser beam involved. As well as being able to print banners, not just cut sheet paper.
The LEDs are set at 1/1200th and they can indeed print disernably different quality when they use their full capacity. The only trade off is time to first print and the need to have a lot of RAM for full page SRA3 photographs . Probably why most people set them at 300 dpi to get nearly instant printing.
John... You seem to be knowledgable in the area of RIPs and platemaking so here's a question you might care to answer. Suppose my platemaker can make a plate at 5080 dpi. (Forget the screening pitch for now) how do send an inDesign document to the platemaker at 5080 dpi resolution? For that matter how do I send any device a document at more than 600 dpi using inDesign? Answer that and you've answered my original question.
The percularity of indesign is that unlike Photoshop, you can't define the resolution of a document at the point of creation. I haven't been ableto define it at the point of delivery either. The only way I can import an indesign PDF into a my pagesetter is to interpolate the images to 1200 ppi seperately from the text and line art which can be 300 dpi or ppi without showing discernable difference. Perhaps your reply in this area was regarding text, not images?
"John... You seem to be knowledgable in the area of RIPs and platemaking so here's a question you might care to answer. Suppose my platemaker can make a plate at 5080 dpi. (Forget the screening pitch for now) how do send an inDesign document to the platemaker at 5080 dpi resolution? For that matter how do I send any device a document at more than 600 dpi using inDesign? Answer that and you've answered my original question."
ID's "Print Presets" for Postscript output are based on the RIP's PPD. Since I do not have a RIP connected to my current workstation, the preset defaults to 'device independent'. The only setting for resolution is the transparency flattener which can be set to "High Resolution". You should be able to use the Xerox's RIP PPD in the "Print Presets" under File > Print Presets; where the output resolution should be able to be established. My hunch is, you may have to settle for "High Resolution" and the RIP will output the highest resolution available in the Xerox machine ( if there are no options for resolution in the presets ).
"The only way I can import an indesign PDF into a my pagesetter is to interpolate the images to 1200 ppi seperately from the text and line art which can be 300 dpi or ppi without showing discernable difference. Perhaps your reply in this area was regarding text, not images?"
No. This is backwards. Text and line art is set at output resolution ( i.e., 2540dpi ). You would definitely see a different between 300dpi vs. 2540dpi, especially in small text and the smoothness of lines. Adobe has a Postscript formula for output resolution. I quote from their Print Publishing Guide "The maximum number of grays that most output devices can produce is 256." Their Postscript formula is ( output resolution ÷ screen ruling )2 [ squared ] + 1 = shades of Gray. So, typical offset imagesetter = 2540dpi ÷ 150lpi = 17 x 17 = 289 + 1 = 290 levels of gray. More than enough to generate smooth blends. In short, lasers ( or, in your case, LEDs ) typically cannot generate enough resolution to produce what you want. Which is 1200ppi image resolution(?). 1/1200 LED is about half of what you need for the resolutions you're looking for.
The long and short of it is this. InDesign is capable of setting its resolution as "High" for raster setting ( i.e., transparency flattener ). I agree with you it is frustrating that you cannot set the output res anywhere in ID. I believe that is because it ( the resolution ) is left up to either the RIP or the Print Driver ).
"The perplexing thing I have yet to find the answer to is:
Commercial printing presses print at 2400 dpi. (let's not confuse the issue here with lpi screens)"
No. The standard is 5080dpi; 2540dpi is minimum ( see my Postscript levels of Gray formula above. When I prepare an ID file for offset printing, I first have to determine the print vendor's RIP LPi. This number determines image resolution which, typically is referred to as 2x the LPi. LPi is ( or should be ) determined by the press itself, the paper, and the inks. Desktop lasers are totally different. InDesign does the user a favor by defaulting to device independent so that multiple file do not have to be generated for proofing. Adobe leaves the print resolutions up to the output device.
I'll save you some time here. The OS is Windows7 and XP Professional.
A hint to the answer I needed was provided in the ID forum. I now know that ID by default will resample images to either 300 or 600 dpi unless you specify it to send all the image data. Then it will indeed print at the printer's resolution of 1200 dpi and produce photographic quality images that look like photographs.
LED printers (as opposed to Laser printers) use the same technology as photo printers do. I also have a LED head for my Durst photo enlarger. It prints at a higher resolution than the Xerox but even when I enlarge past it's optimum size, (fake 1200 dpi) the quality was better than I got from indesign and about what I got from 1200 dpi Photoshop output.
I knew because I'd read somewhere about ID sending full size images that it could be done. I just didn't realize the instruction would be so cryptic as a three letter "all" option in the print dialogue. Perhaps Adobe should attend to this in the next version update?