View Full Version : large prints

Steve Rosen
6-Jan-2005, 19:02
I am going to produce 24x30 inkjet prints. Will 4x5 transparencies scanned @1200 be much better than 35 mm slides scanned @3200. Printing @360 PPI for each gives me similar file sizes.
I use a 3200 Epson Scanner & Epson 2200 printer

John Caruso
6-Jan-2005, 19:42
Hi Steve,

You have to consider the resolution of the film and the lens. The 4x5 will produce a far better print at that size or any other size over a 35 mm simply due to the limits of film resolution.

Ted Harris
6-Jan-2005, 19:50
Remember too that the resolution numbers specified for consumer flatbed scanners have a healthy dose of hype built in. The maximum resolution of the Epson 3200 is most likely somewhere between 1600 -2400.

Herb Cunningham
6-Jan-2005, 20:12
how does one get 24x30 prints out of a printer that only takes 13 inch wide stock?

Did epson come out with a modification?

Eric Leppanen
7-Jan-2005, 00:14
Steve Hoffmann provides his test results (involving both digital and film capture) here: http://www.sphoto.com/techinfo/dslrvsfilm.htm (http://www.sphoto.com/techinfo/dslrvsfilm.htm). His Epson 2450 effectively resolved little more than 1200 DPI; he returned a newer Epson 4870 after determining that it resolved even less.

Leonard Evens
7-Jan-2005, 07:18
About resolution of Epson flatbed scanners.

One has to distinguish the scanning resolution in terms of pixels per unit length from the resolution of fine detail in terms of line pairs per unit length. Scanners do deliver the requisite number of pixels as stated in their specifications. A perfect scanner would in principle deliver half that in terms of line pairs per unit length, but no scanner is perfect. Better, more expensive scanners come closer to the theoretical maximum, but none achieves it. The Epson 4870, if you scan at 4800 ppi would give you 4800/25.4 ~ 189 pixels per mm. Half that would be about 90 lp/mm, but the Epson 4870 doesn't even come close. However, from various reports I've seen, it seems clear that it does deliver something between 30 and 35 lp/mm. That would be what you would get from a perfect scanner, if one existed, that scanned at between about 1600 and 1800 ppi.

I don't have a 4870, but I have had a 2450 and I now have a 3200. My 3200 delivers about 10 percent better lp/mm than the 2450, and I believe the 4870 does at least another 10 percent beyond that. So perhaps Steve Hoffman just had a bad unit or he was measuring differently.

My Epson 3200 allows me in principle to make 5 to 6 X enlargments which should hold up relatively well even if viewed close up. From normal viewing distances, larger prints should look good.

Michael Chmilar
7-Jan-2005, 10:57
By my calculations, if you scan 4x5 at 1200dpi, and print 24x36, then you are printing at 200ppi.

Scanning 35mm at 3200dpi and printing 24x36 yields 133ppi.

Disregarding the film's resolution, the 4x5 prints will look substantially better. If you can scan the 4x5 at a higher resolution will improve the 24x36 prints very noticably. You should really aim at scanning the 4x5 at ~2000dpi for optimal 24x36 prints.