jaapv Posted February 22, 2007 Share #1 Â Posted February 22, 2007 Advertisement (gone after registration) Please enlighten me, oh experts! My profiling/printing service prints at 150 dpi, which suits me fine, as I generally print at max 60x40cm. That fits the 10Mp of the M8 perfectly. Yet other sources talk about 300 dpi, which would mean resizing my files, which the profiler does for me btw when I send in cropped images. The results a get back from my printer are more than excellent, so no complaints in that department, but how does it work? Link to post Share on other sites More sharing options...
joern Posted February 22, 2007 Share #2  Posted February 22, 2007 Jaap,  Did you already read this?  http://www.leica-camera-user.com/digital-forum/9022-30-x-40-inch-m8-prints.html?highlight=David+Adamson  David shares some very interesting and usefull information.  jørn Link to post Share on other sites More sharing options...
Jamie Roberts Posted February 22, 2007 Share #3  Posted February 22, 2007 Hey Jaap--  If you're getting good results from your printer at 150ppi, I say you're doing nothing wrong  The answer to your question is really, an analysis of a bunch of variables. Here are some of the questions you have to ask to determine optimal print resolution: what device are you using? Yeah, I know this sounds obvious, but it isn't. If I feed my Epson 4000 at its natural input resolution of 360ppi it's very happy. Likewise, if I want to go a bit higher, it deals well with 720 ppi, but its overkill and I don't see much, if any, visual difference. More common is go a little lower for an enlargement, and there I see better results at 180ppi than 175 ppi, for example. This could be the way the RIP I use does things, but in general its good practice to work with the native resolution and resolution evenly divided into that. Another good example of how input resolution varies is the Durst Lambda; it performs exceptionally well with only 200 ppi of input resolution, which means my M8 files can be quite large with no visual degradation. It also gives you a resolution advantage at 400ppi, but this is only meant for critical sharpness on things like text. How big is the enlargement? This is the "what ppi can I get away with without having to interpolate more resolution than the file has" question, followed quickly by "what method can I use to interpolate data to the native printer input resolution without losing detail" All that depends on how big you make the print, and what you're working with to begin with. What viewing distance will people look at this thing? You demand more if you're looking at a print with a loupe. You demand less if the print is big enough that normal distance is 6 ft away This is related to the above question What media will you use? Some media "maxes out" its resolution, some demands more. Classic example is printing on fine art papers or canvas, which can only show so much resolution due to the texture of the media itself. Some media fills with ink more or less, so the printing method (not just the device) makes a difference too (pigments have different qualities than dyes, for example). Dmax makes a difference too insofar as the depth of black, especially, can help things look more or less sharp (because apparent sharpenss is also related to contrast). If the media limits this, ppi alone will not increase the apparent sharpness. What sharpening algorithms are amenable to the device and the media? Some work with a lot of post-process sharpening, some don't--you can very quickly oversharpen with some devices but not so much with others. In other words, you need to pull more than resolution to get a sharp print. Finally, the context matters too: lighting and the purpose of the print all enter in to what the viewer expects of sharpness and resolution. Color gamut helps here too; you can do things with colour transitions and dithering that raw input resolution doesn't speak to... So in many cases, "less ppi input resolution" is more than enough. All of this explains why excellent printing is such a technical art, when you want the very best, and why guys like David Adamson are in such high demand with top-end photographers.  So if you're getting good results with 150ppi--don't fix what isn't broken But these are at least some of the questions to consider. Link to post Share on other sites More sharing options...
jaapv Posted February 22, 2007 Author Share #4 Â Posted February 22, 2007 Well, these guys are using a Canon iPF 9000 and an Epson 4800, so I would imagine they should get decent results. Anyway, it may well be that they are resizing before printing without telling me.... Link to post Share on other sites More sharing options...
Jamie Roberts Posted February 22, 2007 Share #5 Â Posted February 22, 2007 Jaap-- Â Do a test run on the 4800 and supply 180 ppi and see if that's better. Might be Link to post Share on other sites More sharing options...
jaapv Posted February 22, 2007 Author Share #6 Â Posted February 22, 2007 Thanks for the tip Jamie. Will do. Link to post Share on other sites More sharing options...
Hans Roggen Posted February 22, 2007 Share #7 Â Posted February 22, 2007 Advertisement (gone after registration) And the Canon? (which is what i'm using) Â Good question Jaap. I've been wondering about this too. Â Hans Link to post Share on other sites More sharing options...
DaveEP Posted February 22, 2007 Share #8  Posted February 22, 2007 And the Canon? (which is what i'm using)Hans  I have been using 150 / 300 / 600 for the Canon because it puts down 2400 / 4800 dpi (depending ont he model). Now wait for some one to come along and tell me this is all wrong  I understood the Epson to be 180 / 360/ 720 because it puts down 2880 dpi.  Note: For people who are unsure, inkjet printers put many more dots per inch down on the page than there are pixes per inch, and that dpi is not the same as ppi. But then most people know that right ? Link to post Share on other sites More sharing options...
ChrisC Posted February 22, 2007 Share #9 Â Posted February 22, 2007 ....... it may well be that they are resizing before printing without telling me.... Â I rather doubt that, but it is possible. As Jamie pointed out the Epsons natively run at 360 recommended though 180 may be fine. Â The 'standard' DPI of the Off-set printing industry is 300. I know of a 'fine Art' print service run by a photographer with extensive experience of sending files for Off-set printing who asks for customers sending him 'fine-Art' files for [printing on large format Epsons] to be written at 300 DPI. He, and others like him, simply has not read the Epson manual and he is none the wiser. Â ..................Chris Link to post Share on other sites More sharing options...
jaapv Posted February 22, 2007 Author Share #10  Posted February 22, 2007 I have been using 150 / 300 / 600 for the Canon because it puts down 2400 / 4800 dpi (depending ont he model). Now wait for some one to come along and tell me this is all wrong  I understood the Epson to be 180 / 360/ 720 because it puts down 2880 dpi.  Note: For people who are unsure, inkjet printers put many more dots per inch down on the page than there are pixes per inch, and that dpi is not the same as ppi. But then most people know that right ? I do - just being sloppy.... Link to post Share on other sites More sharing options...
wparsonsgisnet Posted February 22, 2007 Share #11 Â Posted February 22, 2007 I have been doing the same thing that Dave does; that is, I make sure the dpi I am asking for divides into the printer dpi with no left-overs. Â The Epson 2200 give me 1440 (or 2880?), so I use 240 or 360. If I use 300, the quotient is 4.8. Â When I posted this in another thread, only one person expressed interest and no one confirmed that it made any sense. Â I just figure that PS is doing enough without having to make up parts of pixels. Link to post Share on other sites More sharing options...
jaapv Posted February 22, 2007 Author Share #12 Â Posted February 22, 2007 Parts of Pixels; POPs ? Link to post Share on other sites More sharing options...
wparsonsgisnet Posted February 22, 2007 Share #13 Â Posted February 22, 2007 Lol, Pop. Link to post Share on other sites More sharing options...
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