Epson V750 with Vuescan won't scan at 6400 dpi

[Noah A]

Title says it all. I just picked up a new Epson V750 to use for test scans and low-res scans to save time and wear and tear on the Howtek.

I'm actually quite happy with the machine so far. I've been using Vuescan and scanning to a 'raw' tiff, then inverting and toning in photoshop. While the scanner may not really have 6400dpi of real resolution, my testing (scanning smaller sections) has shown that the results are noticeably better when I scan at 6400dpi and downsize in photoshop than if I scan at a lower dpi setting.

But I can't get a full 4x5 to scan at 6400. My 6x6 negs scan fine, as do smaller sections of 4x5. There are no error messages and vuescan lets me choose 6400, but the resulting files are actually 3200. And yes, I checked the settings in vuescan, there is no size reduction applied.

Any ideas? Is the scanner capable of 4x5 at 6400?

[Doug Fisher]

Many people have experienced issues when trying to scan larger film formats at high resolution. EpsonScan will usually report an error. When I tried something similar in the past, Vuescan did as you described and did not report an error but did complete the scan at the lower 3200 resolution. It really wasn't a big deal to me since the lens is incapable of 6400 ppi of true optical resolution anyway. A scanner that is decent from the factory and set up well will get you somewhere in the 2400-3200 ppi range.

Doug
---
www.BetterScanning.com

[genotypewriter]

Any ideas? Is the scanner capable of 4x5 at 6400?

I've experienced the same. A possible alternative is to scan one 4x5" as several parts (4 should work) and then stitch them up later using some automatic stitching software. If you like scanning at 6400 and later down-scaling you can down-scale the small parts first and then stitch them up later to make the stitched file easier to play with.

[rdenney]

I just observed that the latest versions of Vuescan (starting with ~9.1.12) provide an "image memory" entry in the Prefs tab. The online manual says it needs to be big enough for the number of pixels times the bytes per pixel. For 6400spi and 48-bit color, for example, you'll need about 6300 MB. Obviously, you need sufficient available RAM to accommodate that.

I have not played with this feature, but it may be relevant to this issue.

Rick "who has made scans bigger than this value without issue, but still no bigger than half a gig" Denney

[Noah A]

I had planned on making smaller scans of around 2400dpi. But like I said, based on my tests the results are better when I scan at 6400 and downsize in PS. Interestingly, those results were better even than when I scanned at 6400 and had Vuescan downsize the raw file itself.

I have a slightly older version of vuescan, so I'll have to update, maybe that will help. No way I'm stitching. I got the Epson do do quick (but decent) scans. But I still have my drum scanner for when I need the absolute best quality. I had just planned to scan at 6400, downres to 2400 and save those files for publication, portfolio prints, etc. My ultimate archive scans will be from the Howtek.

I'll try the new Vuescan. Worst case I can scan at 3200 and downsize to 2400, that also seemed to give better quality than scanning at 2400.

[dave_whatever]

Scanning at full res then downsizing to the intended resolution definitely improves shadow noise no end, especially if its an underexposed slide and you're planning to lift it in post.

[bracan]

Use Silverfast:)

[photobymike]

I just observed that the latest versions of Vuescan (starting with ~9.1.12) provide an "image memory" entry in the Prefs tab. The online manual says it needs to be big enough for the number of pixels times the bytes per pixel. For 6400spi and 48-bit color, for example, you'll need about 6300 MB. Obviously, you need sufficient available RAM to accommodate that.


Also the type of computer you use can make a difference in the max resolution. Older PCs only use 3 or 4 gig for max memory. you can put more into them but its top wall is some where around 3 or 4 gigs depending programs loaded. 64 bit computers with an operating system that handles as much memory as you can afford... the exact limits i do not remember. I had a PC with 4 gigs of ram and the most i could scan was 35mm @ 4800dpi with v750. it would have cost me around 4 or 5 hundred to upgrade the memory motherboard and memory....

i found an older G5 MAC with 8 gig of ram for 200 dollars..... shazam it worked like a dream...i could scan at any resolution almost .... 10 gig jpg is really ridiculous... so i had a computer that was a dedicated scan computer.... not a problem to hook into the network for file sharing ..... i have scanned successfully 6x7 negs at the 12,800 resolution on the 7 year old MAC ....

My son loaded Apple Snow Leopard on his HP PC laptop. He uses a my old v700 for very large scans with no problems. Well thats the way i fixed the resolution problem.

To add to rick's solution... sometimes more memory will not work.... you need a motherboard and operating system that will allow use of your extra memory

[genotypewriter]

I had planned on making smaller scans of around 2400dpi. But like I said, based on my tests the results are better when I scan at 6400 and downsize in PS. Interestingly, those results were better even than when I scanned at 6400 and had Vuescan downsize the raw file itself.

As you might already know, there are different rescaling algorithms. It's very likely that VueScan is not using the best one for the types of images that you're scanning.



I'll try the new Vuescan. Worst case I can scan at 3200 and downsize to 2400, that also seemed to give better quality than scanning at 2400.

Not sure if you read my response earlier, but I'll answer this for anyone who might have turned up here after googling the same question... worst case scenario is you have to scan the image in 4 divisions at 6400dpi and then have a good stitching software to put them all in to one image. This could even be thought of as the "better" option because: (1) you don't need to add more RAM just because of VueScan, (2) as you are rescanning with breaks in between, you're also letting the scanner sensor cool down for better noise and (3) you're also reducing the overall heat build-up from the lamp that can affect the flatness of your film.

[Noah A]

...
Not sure if you read my response earlier, but I'll answer this for anyone who might have turned up here after googling the same question... worst case scenario is you have to scan the image in 4 divisions at 6400dpi and then have a good stitching software to put them all in to one image. ...

Thanks for the advice, I did read it and appreciate the response. But as I said above I'm personally not interested in stitching, though it's good that you mentioned it for others.

The whole reason I got the v750 was to do reasonably fast and easy scans for previews, proofs, web and small prints. For final scans I'll use the drum scanner. I realize worrying about squeezing the last bit of quality out of the machine does somewhat contradict my stated needs. But even if I'm looking for quick previews, I'm still interested in maximizing quality within reason.

I'm running vuescan on an Imac. It probably needs more memory.

[Preston]

I think this is an issue with VueScan. I have a MicroTek 1800f and I also upgraded to the latest version of Vuescan (Windows 64-bit). I set the memory allocation in the Prefs panel to 4GB, and no matter what resolution I entered in the Input panel, it defaulted to 1800 ppi. When I was able to use Silverfast, or Microtek's Scan Wizard, I could select up to (I think) 4800ppi.

My computer has 16GB of RAM, an Intel i5 CPU, 1 GB video card and Win 7-64 bit. The machine runs perfectly, so I'm led to believe this is an issue specific to VueScan. I plan to e-mail Ed about this.

I like the idea of scanning at higher resolution and then down-sampling--I just wish I could do it.

--P

[rdenney]

I plan to e-mail Ed about this.

Rather than all of us asking him at once, let us know what he says.

Rick "who has been able to scan up to 3200 on the Epson--the most attempted so far" Denney

[Preston]

Rather than all of us asking him at once, let us know what he says.

Rick "who has been able to scan up to 3200 on the Epson--the most attempted so far" Denney

I've sent a problem report to Ed. Hopefully he can help us out.

It may be helpful if one of you who is having this issue with their Epson to send Ed a problem report and include their VueScan 'Logfile'. Instructions for filing a report are on VueScan's site under 'Suppport (http://www.hamrick.com/sup.html)'.

--P

[Preston]

Update:

I heard back from Ed regarding scanning at dpi greater than optical with my Microtek 1800f. He said this is by design--"you can't set the resolution higher than the optical resolution of the scanner."

I replied back to him today and respectfully asked if scanning at values greater than optical could be added. I also provided him with a link to this thread.

...Research continues...I'll post back when I have any additional info.

--P