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What Actual Megabyte Size Should Negative Scans Be


Well-Known Member
Hi There,
This will be a quick question for you brain boxes out there to answer for a digital duffer like me!!
I have just recieved back from a lab in Guernsey in the UK my first ever digital scans of seven Fuji NPS films.
I requested 18 meg scans for high resolution. (£10.00 per film) so I thought that each film would have a cd of it's own - 18 x 36 = 648 meg. Yet the scans weigh in at 2 to 3 meg a file. And they are grainy as heck when displayed on my 21" monitor. It is like looking at a 1.3 megapixel p&s.
Am I expecting too much, is my maths gone to pot or have they given me the wrong size?
I have tried to contact them today but they appear to be closed for the weekend.

Many thanks,


The files are likely to be JPEG files, which are compressed. Check the file names on the CD for a ".jpg" extension. The compressed data on the CD is decoded back to the full image size when you open the file. To confirm the scanning resolution, just look at the image size. How many pixels wide by how many pixels high? Multiply width pixels by height pixels by 3 and there's your uncompressed file size. The uncompressed file size is shown in the bottom left corner of the Photoshop window. Are you using Photoshop?

The graininess is not unusual for negative film. I gave up using negative film for serious work because it is too grainy. Fuji Reala and Konica Impresa are the exceptions. Use ISO100 slide film if you don't want to see grain in the scans.


Hi Paul, Interesting question. That does sounds like they've given you jpegs which I find suitable for doing web sites etc. To get a decent higher res scan of an entire roll at time of processing the film costs a bit more and typically the lab has to be better than the average mini-lab for it to be worth the price. (One of my local Frontier labs has good equipment, but teenagers they employ to cheaply run the stuff do not care about the result, either that or they just havent' been taught they can do a better job). It could be you're lab suffers the same problem of non-interested work force and they didn't follow your instructions. I've found that to get at least Fuji Frontier lab that does a decent job of hi-res scans as each roll of E6 is processed adds about US$30 to the existing charge of processing the slides. (Cheaper for negatives, but they're too grainy for me)

If I want one exceptional image scanned for something better (say I want to use the image in a brochure, or ad) I send it for a drum scan and tell the lab, or scanning service, that I want a final size of say 9"x12-or-whatever" at 300 dpi, output as CMYK TIFF images. A TIFF of that specification in CMYK mode it will be about 38mb in size. A TIFF in RGB mode it will be about 28mb. (The jpegs would be smaller but suffer from compression, the TIFF does not.)

Does that help? -Lynn
>Posted by Paul matthews on Saturday, July 26, 2003 - 1:06 pm: > >Hi There, >This will be a quick question for you brain boxes out there to answer >for a digital duffer like me!! >I have just received back from a lab in Guernsey in the UK my first >ever digital scans of seven Fuji NPS films. >I requested 18 Meg scans for high resolution. (=A310.00 per film) so I >thought that each film would have a cd of it's own - 18 x 36 =3D 648 >Meg. Yet the scans weigh in at 2 to 3 Meg a file. And they are grainy >as heck when displayed on my 21" monitor. It is like looking at a 1.3 >megapixel p&s. >Am I expecting too much, is my maths gone to pot or have they given me >the wrong size? >I have tried to contact them today but they appear to be closed for >the weekend. > >Many thanks, > >Paul

Something is not right here. I get a roll processed at various one-hour=20 places around here and a scan with a CD costs from $3.95 to $5.95 in=20 addition to the regular processing and 4X6 print set.

The $3.95 is a typical price for the one hour on-site service and $5.95 if= =20 they send it to Kodak.

I generally then get a set of prints, an index sheet, and either 1 set of=20 digital files, or from Kodak I get 3 sets of 3 different resolutions and=20 they are always of excellent quality.

Try a different vendor.

Hi folks,

Thanks for all the replies. It appears that they have given me 6 meg files instead of 18 meg files. I will get onto them first thing on monday and get them to sort it out for me pronto!

Thanks to all,

To optimize the scanning, it is better to scan the film (neg/positve) with the resolution 2000x3000 which will produce 18M tiff file. This number is based on the calculation of average 135 lens resolution.
Any higher resolution scanning will do no/little different with the interpolation in Photoshop. I do suggest you can do a test in scanning the 135 film with different resolution and compare the result with the image interpolation in photoshop. you can get better idea.
By the way, the simple rules for scanning
135 film , 18M tiff
120 film , 40M tiff
4x5 film , 50M tiff
8x10 film, 80M tiff.
One more thing, longer scanning time (in flat bed scanner) may result in burr image due to the vibration.


While your suggested file size may be sufficient in terms of "average" lens resolution, it does not take into account the grain feature size of the emulsion itself. I can confirm from direct experience that there are visible benefits to be gained from scanning much larger files from 135, if you are aiming for large reproductions. My Nikon LS-30 scanner has 2700ppi resolution and produces a 28MB file, which by your criterion should already be lens-limited in terms of sharpness. Scans from the new Minolta 5400 are visibly sharper, however (to put things into perspective, that is a 112MB file). I have written a comparison review on www.photo-i.co.uk which includes a bunch of s&le scans, so you can judge for yourself. I would suggest you take a look at the "Wharf view" s&le, which is shot on ISO100 B&W film using a Planar 50/1.4. The Minolta scan is clearly sharper.


-= mike =-
Hello Folks,
Further to my last thanks, it has been shown my maths is duff. I do have 18 meg files.
I am just not overly impressed with the result. I will load PS7 (never used it before for digital photographs) and see what transpires from there. The lab said they were looking into changing the scans to improve quality (the 5x7 prints were good, they use the same size files to print out, so they say). Looking at what size the new scanners put a file out at, 18 meg seems inadequate. Maybe the next investment is my own film scanner.
Hi Mike,
Sharper doesn't mean higher resolution. The limit of 135mm is about 25M. How to testing the film limit is to taking a resolution chart and then scanning the film by different resolution setting.
I was working in Kodak Professional for very long time and concentrated on digital imaging. And there is a principle in designing "bridge" digital system (i.e. film/paper to digital or digital to film/paper). By using drum scanner, you can scan 135mm film to 100M is very sharp image but the information on the film is same to the file in 50M (i.e. the words of the banner in the image can't be seem in 50M image is still cannot be seem in 100M scanned image). One more thing I should need to mention is that the limiting factor for the CCD scanner is the dynamic range not the resolution. Drum scanner is still have the advantage and can nearly restore/record all the information from the film.
Hi Leo,

> Sharper doesn't mean higher resolution

Fair comment, you can't get back information that isn't there in the first place, but I'm reluctant to accept that the 6Mpixel file you're talking about is able to capture all the detail in a good 35mm frame. However, I believe that the 40Mpixel file produced by my Minolta 5400 gets close (it equates to 106 line-pairs per mm). I've never seen MTF values for top grade optics at 100lpmm, but I suspect there won't be much contrast left at those frequencies, even with the best Zeiss or Leica glass. I see that some drum scanner manufacturers see a need for 15000ppi devices, so I imagine there must be some kind of benefit in going that high or they wouldn't sell any. My guess is that the main benefit would be cleaner, more "analogue" reproduction of the grain structure. Nine times out of ten, when I see a print that is obviously digital, it is the gritty nature of the grain that gives it away.

I agree that dynamic range is a big issue for desktop CCD scanners, but it's stunning how far things have come in the last three or four years. Apparently Minolta quote a Dmax figure of 3.8 for the 5400 (ignore the spurious 4.8D figure -- that is just the dynamic range allowed by a 16-bit number expressed as a log) and from what I see on my K-chrome scans, I'm prepared to believe it. I've also been amazed how little difference 16x multis&ling seems to make, which is another sign that the noise floor is pretty low to begin with.

Speaking of multis&ling, scanning at a high resolution then down-s&ling effectively gives it to you without the extended scan times, so in that respect it also makes a contribution to the dynamic range.

Finally, to draw a parallel with the audio industry, when PCM (CD-type) audio began to catch on in the early 80's it was accepted wisdom that 44.1kHz/16-bit was &ly sufficient. Nowadays 96kHz/24-bit systems are fairly standard, 192kHz s&ling rates are becoming commonplace and the shortcomings of the CD audio standard are almost universally acknowledged. I suspect the small files and limited dynamic range of today's low- and mid-range scanners will be looked at in the same way 20 years from now. The trend is already there; for ex&le I know of one movie post shop which is switching from 16-bit to 32-bit IEEE floating point representation for their image files.

Best regards,

-= mike =-