resolution on Epson 750V

[j-f vergel]

I own an Epson 750V. What resolution would I use on 35mm and on 120 film. The

final image on the 35mm is 11X17 and with the 120 film 10X10? How is this

figure out? I looked at other post and I'm still confused - mathematically

challenged I guess.

 

Also I've read about using Glycerine on wet scans... Any pros? Cons?

 

Thanks,

J-F

[evan_goulet]

So if you want to print your 120 negative at 10" x 10" at 300 dpi, then you need 3000 pixels in each dimension. <P>Assuming a 6 x 6 negative: &nbsp 6 cm / 2.54 cm/in = 2.36 in per side of the 120 negative. So 3000 pixels / 2.36 in = 1271 ppi. (represents the minimum scanning resolution). <P>I typically scan my 120 negatives at 2400 dpi, and re-size in post-processing to my print dimensions. <P>You can figure out the 35 mm similarly.

[j-f vergel]

Evan, Thanks.

[j-f vergel]

That's what I thought... I've been wasting time scanning at a higher res. than I needed.

[mendel_leisk]

With flatbed scanners there's usually some scanning resolution that is the *practical" limit, and it's usually somewhat lower than the scanner's theoretical max resolution. Maybe that would be your best bet, if you can handle the file sizes. While you may only want to print a certain size, you might want to crop and print larger in future. And there may be additional detail that could be resolved, by increasing the scanning resolution.

 

Have a read through:

 

http://www.photo-i.co.uk/Reviews/interactive/Epson%20V700/page_1.htm

 

if you haven't already. It's a fairly exhaustive review of the V700. He reviews the V750 as well, but the V700 review is more complete, and the V750 review mainly concentrates on the differences.

 

On page 10 of the V700 reviews there are a few crops of shots at different resolutions.

[dave_redmann]

<I>Assuming a 6 x 6 negative: 6 cm / 2.54 cm/in = 2.36 in per side of the 120 negative. So 3000 pixels / 2.36 in = 1271 ppi. (represents the minimum scanning resolution).</I><P>

 

Whoa--I disagree with this advice on two counts. First, don't assume how big your negative really is; for example, "6x6" negatives are <I>not</I> 6x6 cm; most common is 5.6 x 5.6 cm. Measure it. So, for example, for a 10x10 inch print at 300 ppi from a typical "6x6" negative, you need the scan to <I>actually deliver</I> (more on that below) 1361 ppi.<P>

 

Second, and more importantly, the resolution <I>actually achieved</I> is (a) likely to be appreciably lower than the nominal resolition setting, and (b) subject to a nearly absolute limit that is <I>much</I> lower than the advertised resolution of any flatbed. As to (a), I would always build in a fudge factor. If you need 1000 ppi, scan at, say, 1200 ppi and scale down. For a variety of reasons you often need somewhat more pixels than the theoretical resolution suggests. As to (b) flatbeds often have claimed resolutions that their optics and/or sensors simply cannot deliver. The older Epson flatbeds were widely viewed as being only capable of delivering 1200-1600 ppi, regardless of the claimed resolution. The V750 is supposed to be somewhat better, but I would be surprised if it gives meaningful additional detail at its highest resolution (4800+ ppi), versus, say, 2400 ppi.

 

Third, a reality check is the film resolution. For example, Fuji only claims that Velvia will deliver >= 50% MTF response out to about 45 lp/mm, which works out to roughly 2300 ppi. Yes, there is <I>some</I> detail preserved finer than that. Yes, you want to scan at a somewhat higher resolution than you need. But scanning Velvia at more than 3600-4000 ppi is just not going to give you any real improvement, and that's accounting for the scan resolution 'fudge factor'. The point of all this is that, to get an 11x17-inch, 300 ppi print from a 35mm film scan (without upsampling), you'd need the scan to actually achieve 3600 ppi (or 71 lp/mm). Few films really contain appreciable detail at this level.

[mendel_leisk]

I would pick some of your fine-grain film with well-lit, well focussed fine detail, scan it at various resolutions, and compare in photoshop. Then try a little unsharp mask and compare some more.

[godfrey]

I did some of the testing that Mendel suggests with the V700 model and found that it's

effective maximum resolution was slightly less than the 2820 ppi of the Minolta Scan Dual II

and 2900 ppi of the Nikon Coolscan IV ED.

 

So I use it set to 3200 ppi... Scanning at higher resolutions increased data size but provided

little additional information to work with.

 

Godfrey

[j-f vergel]

All good info... Thanks all.