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Author Topic: Scanner resolution?
Mike Heenan
Phenomenal Film Handler

Posts: 1896
From: Scottsdale, AZ, USA
Registered: Mar 2000


 - posted 11-26-2004 07:24 PM      Profile for Mike Heenan   Email Mike Heenan   Send New Private Message       Edit/Delete Post 
I was wondering what's the bare minimum dpi for quality scans that I should look for in a scanner? I'm not looking at something high end, but something enough for photos, etc.

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Adam Martin
I'm not even gonna point out the irony.

Posts: 3686
From: Dallas, TX
Registered: Nov 2000


 - posted 11-26-2004 09:37 PM      Profile for Adam Martin   Author's Homepage   Email Adam Martin       Edit/Delete Post 
That really depends on what you want to do with your scans.

Always look at the OPTICAL resolution of the scanner. Any other number takes the scanner's optical resolution and makes up the rest of the data on the scanner's best guess at what it should be.

Most home-level scanners have an optical resolution of 1200x1200 now, which should be adequate for most non-professional jobs.

From there, you tell the software what resolution you want to scan at. If you're just going to look at it on the computer screen, 100 dpi is fine. If you're going to print it out the same size, 300 dpi is fine. If you're going to do any adjusting or blowing up, scan at a higher resolution.

Typically, I scan at 300 or 600 dpi for prints (more if I'm going to need to do any adjusting) or 2400 dpi for slides to prepare the photos for the web.

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Bobby Henderson
"Ask me about Trajan."

Posts: 10973
From: Lawton, OK, USA
Registered: Apr 2001


 - posted 11-26-2004 11:01 PM      Profile for Bobby Henderson   Email Bobby Henderson   Send New Private Message       Edit/Delete Post 
Epson has affordable flatbed scanner models capable of up to 4800 X 9600 dpi/ppi optical resolution. That's usually more than enough rez for a lot of tasks.

Newspapers typically don't need photo artwork any better than 200 dpi. Even for most color magazines, which typically feature line screens or halftone frequencies between 133 and 200lpi, 300dpi would be good enough. Generally you want to scan around 1.5X to 2X the amount of your output screen.

If you're scanning in line art, graphical work, etc. then the higher resolutions can come in more handy. For instance, I'll get the task sometimes of having to reproduce some tiny logo on some shitty business card. The larger and more "focused" I can get the thing into the computer makes the reproduction process easier.

High resolutions are also very necessary when scanning transparancies, like film strips, slides, etc. Most flatbed scanners have a disadvantage from the glass in the scanning bed. Sometimes you can get a "Newton ring" thrown into your aquired image. That artifact looks a little like the halos some lens elements will transfer into a photograph.

For screen based work, such as web pages, the "dpi" or "ppi" thing doesn't mean shit. You just work in absolute pixel numbers.

Resolution alone isn't everything. You also need to look at things like dynamic range capability. Scanners that aquire only reflective art (such as paper, photo prints, etc.) will not capture the amount of color fidelity available in transparent art, such as film negatives, slides, etc. Generally, dedicated slide scanners will offer better color fidelity than flatbed scanners when it comes to film-based scans.

Of course, the kings of the hill on scan quality are still those very expensive drum scanners. They don't use CCDs and cold cathode lamps. Instead they use photomultiplier tubes. Often they can scan in higher resolutions and capture much richer more true color than most flatbed units. In motion picture CGI work, most film plates are scanned into computer systems using very carefully calibrated drum scanners.

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Steve Kraus
Film God

Posts: 4094
From: Chicago, IL, USA
Registered: May 2000


 - posted 11-27-2004 12:45 PM      Profile for Steve Kraus     Send New Private Message       Edit/Delete Post 
quote: Bobby Henderson
In motion picture CGI work, most film plates are scanned into computer systems using very carefully calibrated drum scanners.

Hmmm...I've not heard of that. You're obviously referring to a still of some sort. Usually "plate" refers to a motion picture background composited via traveling matte (blue or green screen, nowadays composited digitally) or used on set for front or rear projection. How often would a still image background be digitally composited with a motion picture foreground?

"Scanner Resolution" ought to be Scanners: Resolution a sequel to the brain exploding movie. [Razz]

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Bobby Henderson
"Ask me about Trajan."

Posts: 10973
From: Lawton, OK, USA
Registered: Apr 2001


 - posted 11-27-2004 01:18 PM      Profile for Bobby Henderson   Email Bobby Henderson   Send New Private Message       Edit/Delete Post 
Yeah, I was referring to background plates or "photogrammatery" images to be used in CGI compositions. Large format stills or a multitude of 35mm shots for "photogrammetery" work would normally be drum scanned to get the best results.

In the case of "photogrammetery," still images get thrown into the foreground all the time. Take the exploding apartment scene from "Fight Club" for instance. The whole kitchen is really a digital model, right down to the tea kettle on the stove. Photographs are texture modeled onto the objects. The technique is the reason why you don't see a camera reflection on that chromed tea kettle.

Naturally, you can't put a long roll of film negative into a drum scanner. For scanning in film negatives, you have a variety of film recorders. Most seem to be CCD-based, which really isn't as good as using photomultiplier tubes. Arri's "Arrilaser" film recorder is one of the best one the market. It uses an unusual laser system to record images, has tuned profiles for specific types of film stock and can record at 4K resolution.

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Adam Martin
I'm not even gonna point out the irony.

Posts: 3686
From: Dallas, TX
Registered: Nov 2000


 - posted 11-27-2004 02:00 PM      Profile for Adam Martin   Author's Homepage   Email Adam Martin       Edit/Delete Post 
I think this is *way* more than what Mike is planning. [Wink]

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John Hawkinson
Film God

Posts: 2273
From: Cambridge, MA, USA
Registered: Feb 2002


 - posted 11-27-2004 03:34 PM      Profile for John Hawkinson   Email John Hawkinson   Send New Private Message       Edit/Delete Post 
"For scanning in film negatives, you have a variety of film recorders" [Confused]
Umm...

film recorders record film (both MP and still). telecines scan MP film. Trying to scan film with an ARRIlaser would be...interesting.

--jhawk

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Bobby Henderson
"Ask me about Trajan."

Posts: 10973
From: Lawton, OK, USA
Registered: Apr 2001


 - posted 11-27-2004 04:35 PM      Profile for Bobby Henderson   Email Bobby Henderson   Send New Private Message       Edit/Delete Post 
Damn, I should have read more about that thingie other than the blurb from Siggraph. An "HD tape to Film" thing would have been nice.

Nevertheless, when it comes to scanning still images on film nothing beats a quality drum scanner. CCDs don't do as good a job as PMTs.

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John Pytlak
Film God

Posts: 9987
From: Rochester, NY 14650-1922
Registered: Jan 2000


 - posted 11-29-2004 10:14 AM      Profile for John Pytlak   Author's Homepage   Email John Pytlak   Send New Private Message       Edit/Delete Post 
Kodak designed and builds the 2K and 4K film scanners used in the Thomson Spirit datacines:

http://www.kodak.com/US/en/motion/products/v2/sehlin.shtml

quote:
...we showed a new high-speed scanner, along with Thomson. It's a 2K/4K scanner that is about five times faster than the next fastest scanner, which also happens to use our technology: the Thomson Spirit DataCine, a tool that has revolutionized the use of digital imaging techniques. This new scanner captures uncompressed image data and does it at rates that were unheard of just a few years ago. We believe this will help drive the move toward digital intermediate technology.
Kodak CineSite also has information on the scanners it uses:

http://www.cinesite.com/?1231&0&1269

quote:
NORTHLIGHT SCANNER

Cinesite recently installed Northlight film scanners at both the Los Angeles and London facilities. This new generation of scanners, developed by FilmLight in London, utilizes an 8K tri-linear CCD array manufactured by Kodak to convert film at either three- or four-perforations of height per frame to digital files. Cinesite can now scan 35 mm color negative film at speeds around four times faster than the previous generation of machines making it more practical to convert nuances in colors, contrast and other details captured on the original negative to digital files.
KODAK LIGHTNING 35MM SCANNER

The Lightning film scanner, the finest system available for digital imaging, is the cornerstone of Cinesite's scanning capability. Featuring CCD sensor technology with three linear photosite arrays of 4,096 pixels each, the scanner handles the most common 35mm aspect ratios of Full Aperture (1024,2048 & 4096 lines resolution), Cinemascope and Academy (914, 1828 & 3656), and Vista Vision format (6144).
At 4000 lines, the Lightning scanner captures 38.9mb of data per frame from the standard 35mm format, Cinemascope captures 45.5mb, Full Aperture 51mb and Vista Vision exactly 100mb. The 4000 line resolution provides more than sufficient headroom for the level of image manipulation upon which our customers stake their reputations.
Each CCD array has a custom filter tuned to the dye densities of Eastman Color film, and is capable of capturing the full dynamic range of the images being scanned.
GENESIS PLUS 65MM SCANNER

Cinesite is excited about the tremendous growth happening in the large format, special venue industry. The Kodak Genesis Plus scanner brings the same dynamic and robust digital tools to the 65mm wide-screen filmmaker that are available with the 35mm Lightning scanner. The Genesis Plus handles 5, 8, and 15 perf formats.

Kodak makes a wide variety of very high resolution CCD sensors (up to 22 megapixels) for use in digital imaging:

http://www.kodak.com/global/en/digital/ccd/sensorsMain.jhtml

Kodak Linear Array sensors used in color scanners have up to 14,400 pixels across their length for red, green and blue:

http://www.kodak.com/global/en/digital/ccd/products/linear/linearMain.jhtml

quote:
Linear Image Sensors Family Overview

Features

Family of devices (up to 14,400 pixels; color or monochrome)
High dynamic range (up to 16 bits)
Pinned photodiodes for low lag and dark current
Channel independent electronic exposure control
Single output per color, including multi-readout register architectures
High data rates (up to 120 Mhz)
Kodak monochrome and color linear imagers are available for use in flatbed scanners, high speed document scanners and copiers, machine vision cameras, studio photography, and satellite imaging.



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Bobby Henderson
"Ask me about Trajan."

Posts: 10973
From: Lawton, OK, USA
Registered: Apr 2001


 - posted 11-29-2004 11:45 AM      Profile for Bobby Henderson   Email Bobby Henderson   Send New Private Message       Edit/Delete Post 
Pretty cool stuff, John. Glad to see 65mm is being included in the developments.

Is the "de facto" status of 2K starting to break down in favor of a higher quality movement to 4K for CGI and digital intermediate work? For instance, are there any noteworthy titles using 4K that we can look forward to viewing?

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John Pytlak
Film God

Posts: 9987
From: Rochester, NY 14650-1922
Registered: Jan 2000


 - posted 11-29-2004 01:10 PM      Profile for John Pytlak   Author's Homepage   Email John Pytlak   Send New Private Message       Edit/Delete Post 
I recall that both "Stuart Little 2" and "Spiderman 2" used 4K scanning and output, but may have used less resolution for the image processing and CGI:

http://www.kodak.com/country/US/en/motion/forum/featureFilms/stuartLittleP.shtml

quote:
Stuart Little 2 was produced in Academy aperture format (1.85:1 aspect ratio). In retrospect, Poster says that if he had known they would be digitally timing and recording a 4K master he would have tried to convince the producers and Minkoff to film Stuart Little 2 in Super 185 using more of the available negative space for the same aspect ratio.

...The film was scanned at Image Works at 4K resolution. Poster says that provided the headroom necessary to retain subtle details, including mouse whiskers, fur, feathers and textures that help to provide the filmatic look audiences associates with fantasy.


As 4K scanning/recording speeds increase and costs come down, I'm sure more films will be done at 4K, as it does significantly improve the image quality on screen. [Smile] [Cool]

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Steve Kraus
Film God

Posts: 4094
From: Chicago, IL, USA
Registered: May 2000


 - posted 11-29-2004 04:28 PM      Profile for Steve Kraus     Send New Private Message       Edit/Delete Post 
Well I certainly would hope Spidey 2 used 4K what with some effects being shot in 65mm!

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Mike Heenan
Phenomenal Film Handler

Posts: 1896
From: Scottsdale, AZ, USA
Registered: Mar 2000


 - posted 12-08-2004 08:00 PM      Profile for Mike Heenan   Email Mike Heenan   Send New Private Message       Edit/Delete Post 
Thanks for all the tips guys, I decided on a HP scanner all in one unit (printer, scanner and copier) that does 600x2400 scans, is that pretty good for home use (scanning papers, etc, photos for color restoration, and whatnot), the 1315 model I believe. I dont intend on doing any high end graphic work so I dont need anything that expensive. Do you think this would be a good enough deal at $100, or should I get one of those higher optical rez scanners 2400x4800 at about $100 more or so?

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Adam Fraser
Master Film Handler

Posts: 499
From: Houghton Lake, MI, USA
Registered: Dec 2001


 - posted 12-09-2004 12:48 AM      Profile for Adam Fraser   Author's Homepage   Email Adam Fraser   Send New Private Message       Edit/Delete Post 
Mike,
We have a similar model at one of our furniture stores. It works just fine for making copies/scanning/etc. For $100.00 it works pretty good. At home I have a $50.00 cheapie parallel port scanner that also works decent.

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Joe Redifer
You need a beating today

Posts: 12859
From: Denver, Colorado
Registered: May 99


 - posted 12-18-2004 08:27 PM      Profile for Joe Redifer   Author's Homepage   Email Joe Redifer   Send New Private Message       Edit/Delete Post 
Somebody recommend me a scanner! I am leaning towards Epson. Brad likes his Epson and I used my dad's Epson recently and it turned out some nice scans. I really don't care about scanning negatives or film, but that feature sure wouldn't be a burden to have, especially when I scan all the frames of a print one by one and reassemble them in Final Cut Pro so I can pirate the movie. I am looking for specific model numbers. Nothing too cheap but nothing mega-expensive either.

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