Could be the wrong way to go on my part, but I tend to try and avoid resizing if possible. For A4 I would first try and go for (by your calculations) 240ppi or 288ppi and either crop the image or have a white border and cut to size. I wouldn't want to go below 144ppi though, so would have to do some resizing to get to A3.
I have read in numerous places (don't know where offhand) that epson printers work best with a ppi of 300 and Canon works best with 360 - kinda like a native resolution for the driver. I would be interested to know whether results were best by ressing up the number of pixels and keeping at a high ppi or by dropping the ppi. I am sure I have read that it is better to let the printer work at a lower ppi than use the interpolation of adding new pixels. I am not going to bother testing this on my 6 year old Epson which is being replace this Xmas, but would be interested to hear other opinions/experiences - especially if someone wanted to do a proper test on a modern printer... Rob > -----Original Message----- > From: Cotty [mailto:[EMAIL PROTECTED] > Sent: 31 October 2003 09:33 > To: pentax list > Subject: Printer resolution (was: Re: posted *istD Samples) > > > On 31/10/03, [EMAIL PROTECTED] disgorged: > > >> > The 11" print was then compared to a 11" print I made > from scanned > >> > 4"X5" ektachrome 100. The ist image has remarkable lack of > >> > grain/noise and looks virtually as good as the 4x5 print in that > >> > respect. The resolution however is clearly not at the > same level > >> > when examining with a loupe. This is exactly as I expected. > > > >But, how many people view an 11" print through a loupe. Most folks > >hang one that size on the wall and view it from several feet away. > > This raises a very interesting point. I have been re-reading > Photoshop for Photographers by Martin Evening and I came > across a section on printing resolution that I didn't recall. > > In it, the author says that > > 'the optimum pixel resolution [of the printed image] should > ideally be the printer dpi divisible by a whole number. The > following pixel resolutions should be used [for a 1440/2880 > printer] : 144, 160, 180, 240, 288, 320, 360. To make large > inkjets for viewing at a greater distance, use a low pixel > resolution. For smaller sized portfolio prints I normally use > a 240 ppi resolution. I doubt very much you will notice any > improvement in print quality if you choose a resolution that > is higher than this.' > > This subject has been discussed on the list before, but what > with the recent arrival of the *ist D into many eager Pentax > user's hands, it may be of interest again now. > > Off the starting blocks I have always been printing at 300 > dpi and always been very happy with the results. I think I > tried 200 dpi once and noticed the difference. My image size > out of the (light-tight) box is 3072 pixels by 2048 pixels > with a file size in Photoshop of 18 MB (from a large/fine jpeg). > > If I change the resolution to 300 ppi (without changing the > dimensions - file size - that is without getting Photoshop to > interpolate extra info into the image) then my physical size > of print will be 26cm by 17cm or thereabouts. That's roughly > 10"X 6 1/2". So at 300 ppi, if I want to fill a nice A3 > print, I would normally increase the size to (say) 40cmX26cm, > also increasing the pixel count from 3072X2048 to 4724X3150, > and bumping up the file size from 18 MB to a whopping 42 MB. > Photoshop interpolates very well and the prints are really nice. > > But now if I change things slightly and select a resolution > of 240ppi as Mr Evening suggests, the size increase is much > less in terms of added Photoshop interpolation. 3072X2048 > goes up to 3780X2520, and file size jumps from 18MB to only 26MB. > > I don't really have a question in starting this thread, > rather just the above observations. It's my last day off sick > (I'm feeling much better after being attacked by a flu bug) > so I'll be using a bit of ink up doing some tests. > > Any thoughts / comments / pointers ? How do you do it ? > > > > > Cheers, > Cotty > > > ___/\__ > || (O) | People, Places, Pastiche > ||=====| www.macads.co.uk/snaps > _____________________________ > Free UK Mac Ads www.macads.co.uk > >
