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View Full Version : need help: negs sharp at 300dpi but 2400 dpi is super soft



Heespharm
6-Apr-2011, 22:04
So i'm trying scan my 4x5 and 2 and 1/4 negs and the 300dpi preview looks sooo much sharper than the 2400dpi scans...

what gives???

I know the neg is sharp from past enlargements but scanning looks soft...

scanner: epson 4990 using included frame masks
program: vuescan


the only thing that makes it better is downsampling the negs to 600 dpi...

any hint or tips at scanning to get my negs sharp?

David de Gruyl
7-Apr-2011, 05:52
are they in focus? Particularly, is the grain in focus? I'm not sure whether the 4990 has two lenses, but the current iteration (700/750) has two lenses which are used for different magnifications. One focuses above the surface of the glass, while the other focuses "on" the glass platen. The (stock) negative holders have little feet which can be used to adjust the height up or down ~1/2 mm.

If focus is not your problem, you have some settings wrong. Another option is to sharpen the image after you scan it, but what are you looking for?

Can you post an example of the problem?

Gem Singer
7-Apr-2011, 06:14
2400 dpi is pushing the limit of the Epson 4990. Do you get the same lack of sharpness at 1200 or 1600dpi?

If so, you might find the solution to your problem at: www.betterscanning.com

Math
7-Apr-2011, 06:20
Of course something will look 'sharper' when you downsize it, just like a grainy negative will look less grainy when you just do a contact print. However, the problem is not the negative, but the scanner. I've yet to find a flatbed that gives me scans that don't look soft at a 100% level at close to max DPI.

engl
7-Apr-2011, 06:34
The MTF curve (contrast vs. cycles/mm) of the 4990 (and V700/750) is not very flat, it resolves fine detail but is going to need sharpening for that detail to have the same contrast as the source negative. An unsharpened image from these (or really most consumer flatbeds) is not representative of the quality obtainable in the final image.

I've seen 1600DPI quoted many times as the measured real resolution limit of the 4990, I'd expect to get pretty close to this limit by scanning at 2400DPI and downsampling to 1600. To get to the resolution limit you will also need to get focus right, which can be tricky as the 4990 does not height adjustable holders. You can buy after-market adjustable holders from www.betterscanning.com . Before going this route, I'd use some makeshift solution to find the peak performance at optimal height, and see if this differs from the performance using the stock holders.

David de Gruyl
7-Apr-2011, 06:41
The MTF curve (contrast vs. cycles/mm) of the 4990 (and V700/750) is not very flat, it resolves fine detail but is going to need sharpening for that detail to have the same contrast as the source negative. An unsharpened image from these (or really most consumer flatbeds) is not representative of the quality obtainable in the final image.

This is really true of any scanner. I'm still trying to figure out whether the OP is talking about sharpening or focus, however.

My normal workflow is to scan unsharpened and sharpen in software afterwards. Other people probably do it differently.

Heespharm
7-Apr-2011, 08:29
Thanks guys

This softness is at anything above 600 dpi... It looks mushy like the whole neg is out of focus... I am using a antinewton glass from better scanning for my 2 and 1/4 negs

Ben Syverson
7-Apr-2011, 08:40
Maybe the negative is out of focus

Heespharm
7-Apr-2011, 09:40
Maybe the negative is out of focus


I've already enlarged/printed this neg via analog... It's sharp

engl
7-Apr-2011, 09:54
This is really true of any scanner. I'm still trying to figure out whether the OP is talking about sharpening or focus, however.

My normal workflow is to scan unsharpened and sharpen in software afterwards. Other people probably do it differently.

Yes, indeed any scanner behaves like this, but the effect is a lot more pronounced with flatbed scanners compared to for example drum scanners.

From the last message about softness even at 600DPI, my guess would be that it is a focus issue (of the scanner, not a soft negative).

Heespharm
7-Apr-2011, 20:04
yeah seems like a focus issue... do you think i should try scanning with the neg directly touching the glass?

David de Gruyl
8-Apr-2011, 04:02
yeah seems like a focus issue... do you think i should try scanning with the neg directly touching the glass?

the first thing I would try is putting some shims (paper?) under the feet of the negative holder: if you are lucky, raising it will help. Once you know how far, you can use tape or some such.

a quick scan on the glass is also a good idea, but you need to flatten the negative. If you can, use a piece of anti-newton-ring glass with the AN side to the negative.

Brian Ellis
8-Apr-2011, 08:01
yeah seems like a focus issue... do you think i should try scanning with the neg directly touching the glass?

That's the first thing I'd try since it's the easiest thing you can do. I scanned 8x10 negatives on a 4990 with the negatives on the glass and it worked fine.

Also, when you talk about what's sharp and what isn't, are you basing this on prints or just looking at the scan on your monitor? To really check you should be making prints, as I'm sure you know monitors aren't going to be representative of what you'd see on a print since they have such a low resolution (relative to a printer).

venchka
11-Apr-2011, 11:57
I use EpsonScan with an antique Epson 1680.
4x5 @ 1600 dpi
I apply a bit of capture Unsharp Mask (medium I think) during scanning
Lightroom preset sharpening during edit.
I print small mostly. The occasional 10xwhatever on 11x14 paper.
Output print sharpening: Standard for the paper I'm using (gloss or matte)
Prints look good.

venchka
11-Apr-2011, 13:31
Question:
How do you have the scan input area vs. scan output area set up?
My input dimensions equal my out put dimensions. In other words, 4x5 input @ 1600 DPI = 4x5 output @ 1600 DPI.
Also, be advised that if you are looking at a 100% image @ 1600 DPI, that is the same as sticking your nose up close to a small section of a print 26" long at 300 DPI printing output. Move back.