Optimal Scanning - 35mm, 6x4.5 & 6x7

[jvora]

Hello :

I am about to scan several hundred Color Transparencies and B&W Negatives from my archive on a professional scanner ( most likely either a Hassleblad X1 or X5 Scanner ).

As I would like to undergo this process only once and save the scans for future use, I wish to understand if there is an optimal resolutions that each of the following formats should be scanned at : 1. 35mm, 2. 6x4.5 and 6x7.

Both the Transparency and Negative media are either rated at ISO 100 or below ( 64 and some 25 ).

What I mean by optimal is that a 35mm transparency, if desired, be scanned all the way upto 8000ppi, but that maybe an over kill - What I wish to understand is the optimize data that can be extracted from the media before one hits the proverbial "wall" after which additional resolution will not be a gain.

I will appreciate your guidance / advise based on the above explanation.

Thanks,

Jai

[ErikKaffehr]

Hi!

It would be difficult to give general advice on the issue. The best way is probably to scan at maximum optical resolution of the scanner and than downsample, but that takes a lot of times and the files will be gargantuan in size.

This link may have some clues and has links to some sample images up to 6096PPI: http://www.luminous-landscape.com/forum/index.php?topic=58067.msg472520#msg472520

I would recommend checking out the full thread as there are a lot of comments by knowledgeable persons.

I used a Minolta Dimage Scan Multi Pro CCD scanner. That scanner scans at 3200 PPI for MF and at 4800 PPI for 135. My experience is that little resolution is gained past 1600 PPI with MF Velvia, but I always felt that it was better to scan at 3200 PPI. I have made some stunning 70x100 cm (30x40") prints from Velvia scanned at 3200PPI.


Increasing resolution may give a tighter grain pattern. My guess is that MF Velvia was pretty much limited by lens in my case. Velvia 135 I would scan at 4800PPI.

Check also: http://echophoto.dnsalias.net/ekr/index.php/photoarticles/59-sony-alpha-900-vs-67-analogue-round-2

and: http://echophoto.dnsalias.net/ekr/index.php/photoarticles/16-pentax67velvia-vs-sony-alpha-900

I plan for but never got around to a comparison of 6096PPI and 3200PPI scans, and also on third installment of the above series.

Best regards
Erik

Hello :

I am about to scan several hundred Color Transparencies and B&W Negatives from my archive on a professional scanner ( most likely either a Hassleblad X1 or X5 Scanner ).

As I would like to undergo this process only once and save the scans for future use, I wish to understand if there is an optimal resolutions that each of the following formats should be scanned at : 1. 35mm, 2. 6x4.5 and 6x7.

Both the Transparency and Negative media are either rated at ISO 100 or below ( 64 and some 25 ).

What I mean by optimal is that a 35mm transparency, if desired, be scanned all the way upto 8000ppi, but that maybe an over kill - What I wish to understand is the optimize data that can be extracted from the media before one hits the proverbial "wall" after which additional resolution will not be a gain.

I will appreciate your guidance / advise based on the above explanation.

Thanks,

Jai

[jvora]

Thank you Erik - Am heading to the links you have provided !


Jai

[Mark D Segal]

Jai,

There's input resolution and output resolution. Let's begin with output resolution. What resolution do you want to print at and what is the largest size print you intend to make? Let us say the largest print dimension will be 14 inches and you want to print at 300 PPI sent to the printer. Therefore you need total pixels of 14 inches*300 pixels per inch, or 4200 total pixels. Let us assume the media you are scanning has a large dimension of 1.4 inches (as in a 35mm frame, no cropping). To get 4200 pixels from a 1.4 inch input media, your input resolution needs to be 4200/1.4 or 3000 pixels per inch. When you enter these resolution values into your scanning application, make sure there is no confusion about whether it is input or output resolution you are supposed to enter. Basic idea: don't waste more time and storage space than needed relative to the largest "call" you will ever likely make on that scan. I've heard/read all the differing advice and tried the options every which way, looked at the prints normally and pixel-peeping and for all practical purposes this is the most useful recipe to follow. People obsess about whether to scan at "optical resolution" or other, not remembering that effective resolution in terms of what really comes out on paper is limited by the characteristics of the film, quality of the lens on the camera used to make the photograph and scanner's actual resolution, which is usually below the stated optical resolution - sometimes far below.

[dmerger]

Most scanners have various mechanical resolutions, e.g. a fixed-size CCD and motors that drive the film past the CCD with specific steps (not continually variable). Therefore, if you select a scan resolution that is not supported by your scanner’s hardware, your scanner software will resize the scan produced by your scanner.  Most scanner software does not specify the resizing algorithm used. 

There may be valid reasons to set your desired scan resolution in the scanner software.  My approach, however, has been to scan at my scanners highest mechanical resolution and save that scan as a master.  (I only scan 35mm).  I then work on my scans in ACR/PS and resize as needed for a particular output (always preserving my master). 

Scanning is very time consuming.  So, essentially, my approach is to get the highest quality basic mechanical scan that my scanner can produce, and save these scans as masters.  I never want to have to scan the same piece of film twice.  All my edits are done in ACR/PS in a non-destructive, reversible manner. 

[Bart_van_der_Wolf]

There may be valid reasons to set your desired scan resolution in the scanner software.  My approach, however, has been to scan at my scanners highest mechanical resolution and save that scan as a master.  (I only scan 35mm).  I then work on my scans in ACR/PS and resize as needed for a particular output (always preserving my master). 

Scanning is very time consuming.  So, essentially, my approach is to get the highest quality basic mechanical scan that my scanner can produce, and save these scans as masters.  I never want to have to scan the same piece of film twice.  All my edits are done in ACR/PS in a non-destructive, reversible manner.

I fully agree with that approach. The scanner's highest native scanning resolution is not only chosen for the extraction of whatever resolution was caught on film, it is also chosen to avoid grain-aliasing in a discrete sampling scanner. Once the time consuming scan is done, one optionally could use a quality downsampling algorithm to reduce the file size a bit with minimal loss of resolution. Scan resolutions up to 6000 - 8000 PPI can result in lower graininess/noise scans, but much useful resolution is unlikely to be present above 5000 PPI.

Cheers,
Bart

[elliot_n]

Scan at the scanner's max resolution, and scan in the Hasselblad/Imacon's '3f' format. 3f is a type of raw scan. It makes the scanning a fast and mechanical process - you can scan approx twenty 35mm frames per hour using this approach. You then set the scanning parameters at your own leisure, after the scanning session, on a different computer (you'll need Flexcolor software installed).