Grainy drum scans?

[Gary Tarbert]

Hi, I recently had some drum scans done locally , They appear a little on the grainy side considering they are 5x8 originals from velvia 50 , They were scanned at 13900x 22500 @360 dpi creating 898 mb file any suggestions? cheers Gary

[Frank Petronio]

We were just talking about grain aliasing on the small format thread... Perhaps they scanned them too stopped down?

[Ivan J. Eberle]

That sounds closer to 2800 dpi native than 360 dpi. Are you judging the graininess at 100%? What scanner, was sharpening applied? Have you tried a noise reduction software like Imagenomic Noiseware (or another app) that will allow you to read the noise, then selectively apply a filter in say, the green channel? The best scans I've gotten to date were very fine aperture PMT drum scans. I knew they'd require a little cleanup like I just described, and rather had to plead with Lenny Eiger to scan at 3 and 6 microns on his Aztek. Doing so allowed me to retain fur texture in a mountain lion shot at a slightly cropped final print size of 32"x48" without the image resolution falling apart-- this from a 35mm Astia original!

[Daniel Stone]

if it looks "noisy" or grainy, then the aperture used during scanning is TOO SMALL, but there might be some other things worth mentioning(see 2nd body of text below)...

Velvia 50, when done right, can look marvelous in drum scans... But it has to be exposed right.
When I was shooting RVP50(I now work with a remaining stash of E100G, and Provia 100F), I'd rate it at 40. Under-exposed transparencies(especially RVP50), when brought up in density(think curves adjustment, in pre-scan adjustments before final scan) can translate into increased "graininess" in the scans...

Also make sure that they indeed wet-mounted it... Before I got my drum scanner, I had some done by a local lab/service(I'll not give names, but they're "big" here in LA in the photo world)... I had a similar experience to yours... I found out that they were DRY mounting my film on the drum, to save time/money... I asked them bluntly over the phone if this was the case(since it was the only option I could come to after consulting people more "in the know" than I at the time(and I'm still learning ;), definitely not a master yet), and they said "yes"... Well, I requested they re-do the scans pro-bono(free), and provide me with credit towards more scans down the line... I mentioned that I was "active on online forums where we discuss labs/services for drum scanning", and the chap on the phone eagerly agreed to my terms....

NIGHT AND DAY DIFFERENCE in scan quality between dry and wet-mounted scans.... NIGHT AND DAY... Wet-mounted scans were much cleaner, blacks were blacker, and had less "muddiness" than the dry mount scans done originally...

EDIT: these drum scans I had done were from color negatives and color transparencies(mostly E100G or E100VS, but IIRC, a sheet of Provia or Velvia, can't remember offhand)

Just some options to check into with your lab/service bureau.

-Dan

[Lenny Eiger]

I knew they'd require a little cleanup like I just described, and rather had to plead with Lenny Eiger to scan at 3 and 6 microns on his Aztek. Doing so allowed me to retain fur texture in a mountain lion shot at a slightly cropped final print size of 32"x48" without the image resolution falling apart-- this from a 35mm Astia original!

Ivan, you did have to plead with me. I thought you were crazy. I'm glad I did it, and I did learn from the experience... I now scan one notch down from my usual standards. It turns out there are things that an LCD monitor does that make it look different than it actually is. Prints are better, and scans are sharper.

Lenny

P.S. Ooops, to the op's point: the resolution isn't the issue with grain, it's the anti-aliasing. On a drum scanner, one can match the grain size exactly to the aperture, and that's the way to go.

[Gary Tarbert]

Hi guys , Thanks for the input , You know scanning is the only thing i hate about using film (but a part of the proccess regrettably) I do rate velvia at 40 , Dry scan ?that could be a good question to ask , You see i assumed that wet was the only way you could mount on a drum .Thanks for the software tip Ivan , I will check it out . The only drum scanning service in town is at a company more geared towards print solutions ie corporate banners billboards and the like and is not so much a photographer , So i might get a blank look when i ask him too match the aperture too the grain size . Cheers Gary

[Daniel Stone]

Gary,

Its hard to know the EXACT size of the grain, even with tabular films the grain isn't always the same size ;)

"Matching" aperture size to grain size is usually a multiple step process where one does pre-scans at different apertures until one has the required combination of sharpness(of grain, without aliasing) and smooth tonality.

I usually do 3-5 pre-scans to get things 'just right' per scan, so just the setup time on a drum can be laborious if multiple sheets are mounted.

Some operators might have a flow chart that works well for the broad range of uses, so they can look up a certain film, say "OK, provia, aperture size of 10, etc..." For those of us(myself included) that drum scan our own shots(or for others), tailoring each scan is what makes it all worth it IMO. So each scan is just the way we want it.

Dan

[Gary Beasley]

I've found that the unsharp masking usually done after the scan can be the worst culprit for making the image grainy. If the radius is set to a size too close or smaller than the grain size it will exagerate the grain, Set it two or three times that size and that effect goes away.

[Gary Tarbert]

Hi Guys , Thanks for all the suggestions i learned a lot about scanning pitfalls from your feedback, Turns out he oversharpened them , I got him to rescan and turn the sharpening off ,see being a print outlet he sharpened for final print ,the new scans are far better and now i have some files worth editing :) Cheers gary