Optimal 35mm Drum Scan Size & Settings

[Spiritualized67]

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Hello all. What is the ideal usable size and settings for a 35mm drum scan? In other words, what should I request from an output standpoint (when ordering) to achieve the optimal quality in my 35mm color and B&W negs?

 

I've read that the usable data for 35mm maxes out at around 4,000-5,000dpi (around 100-150MB), but I see some scanners go as high as 11,000 dpi (Tango).

 

I would like to be able to work with an editable digital file capable of being output to large exhibition print sizes (at the best quality possible). Without knowing much about drum scans, I assume they would be output to something like RGB TIFF in 16bit?

 

Any insight in achieving optimal 35mm film to digital quality would be appreciated.

 

Thx. -Dan

[dave_d]

I have always used the formula (scan resolution) = (magnification) * (Output Resolution).

If want want to make an 8x10" print your magnification would be about 8x from 35mm film.

Output resolution is dependent on the type of output device. Usually 240, 300, 0r 360 ppi is normal. Ask the lab doing your printing.

8 x 300 = 2400 ppi scan.

A scan of higher resolution than you need for your output will not increase quality. Although if you are not sure your output size go for the highest scan resolution you can and you will have the option to print large. The down side of the largest scan possible is cost and file size.

 

Hope this helps.

[adan]

There is no point in getting a scan that is higher res (per mm or per inch) than your camera and film can achieve. You'll just be getting better and better photomicrographs of your grain, not real-world detail.

 

For the best "normal" films, with very good lenses - K-25 or Velvia 50 or Ektar 100 or ISO 50-100 B&W - this will be about 125 lines per mm or 3175 lines per inch. If you really want to be sure of imaging "every picket in the fence" without aliasing, you could double that to 6350, but that won't really reveal more detail, just a cleaner image of what detail is there.

 

For anything above ISO 100, the numbers drop, and 4-5,000 ppi will be easily enough.

 

11,000 pixels per inch is gross overkill for anything except perhaps the ultra-low ISO (6-20) B&W microfilms, shot with the best possible APO or Superachromat lens, at its best possible aperture, on a 30-lb tripod or optical bench: http://www.microscopy-uk.org.uk/mag/imgmar07/DDEFig08.jpg

 

It equates to 433 lines per mm - and there are just no films that resolve at that level except (maybe) scientific (or CIA) speciality films.

 

While dave_d is right that a full-res scan may be overkill for smaller prints, it is easy (and free) to simply make a down-sampled copy of a high-res original scan for those smaller prints. It is NOT possible to restore detail if someone admires your 8 x 10 from a 2400-ppi scan, and asks if you can make them a 16 x 20 of the same picture.

 

Conversely, a "right-sized" scan that exactly captures the detail present in the original film, can be uprezzed if needed for even larger prints. It won't contain any more detail, but will make the lab or printer happy.

 

More: Technique - Optimal scanning resolution of photographic film

[Spiritualized67]

Thank you for the information - it is very helpful!

 

~Dan