File sizes from current scanners

[darin_young1]

Just wondering, does anyone know offhand what the maximum file sizes

(in megabytes) attainable are with the current scanners on the

market? Interested in 35mm, 6x6, 4x5, and 8x10 formats from

scanners in the prosumer range (i.e. Nikon 9000 for up to medium

format, and Epson 4990 for large format). And how do these compare

to the maximum file sizes of a drumscan from a professional lab?

<p>

Without getting into a discussion about the costs of each type of

scan, I'm just looking for rough estimates of the sizes. Thanks in

advance!

[._kaa]

Umm... it's rather simple math.

 

Let's take a scan of 35mm film at 4000 dpi in 16-bit color.

 

A film frame is about 1 x 1.5 inches which at the given dpi means the scan will be 4000 x 6000 pixels, or about 24 Megapixels. Each pixel has three channels of color data (R, G, and B) at two bytes each. So 24 Megapixels x 6 bytes = 144 Megabytes. That's your size for an uncompressed scan.

 

You can do the calculations for all the formats/scanners you're interested in...

[byronlawrence]

try to find the "true" resolution from given scanner x... like 4000 dpi for the nikon 9000 and take your film size 6x6 (med format) 6 cm divided by 2.54 cm/in gives 2.3622 inches square and multiply the film dimension (in inches) by the resolution.. 4000dpi by 2.3622 inches gives 9448.82 pixels in one dimension. since the film is square in this case your other dimention will be 9448.82 pixels also. Multiply these two dimentions and you will get the number of pixels (9448.82^2 = 89280178 pixels) and divide by 1,000,000 which gives you 89 Megapixels. however that translates to Megabytes. your on your own. probably close to the same thing if you are in an 8 bit/channel imaage but in 16 bit there are quite a few more Mb of info.

[joe_oliva]

All the best.

[gpb]

<p>I just bought a CanoScan 9950f, and was dismayed when looking through the

documentation when I came to this:

<blockquote>

"The ScanGear CS scanner driver uses an industry common communications protocol

called TWAIN. The ScanGear CS driver will not allow scans that exceed the TWAIN 10,000

x 30,000 pixel limitation at 48 bit color depth. Scanning of large images or 4" x 5" filme

may require reducing the scale, reducing the resolution or adjusting to a smaller scanner

area when scanning"

</blockquote>

<p>I've only scanned 35mm so far (I have a 4x5 camera on order), so I haven't run into

the size limitation, which I will deal with either by using 2400dpi, or stitching together two

4800dpi scans (4x5 at 4800dpi would be huge, so I'd probably only do that for

outstanding images). 4800 dpi scans of 35mm result in PhotoShop files of 175MB.

 

<p>My <a href="http://irgth.com/reviews/canoscan_9950f.php">review of the

scanner</a>.

[steve_unsworth1]

Greg, might be worth trying a copy of Vuescan - www.hamrick.com - to see if that gets round the issue.

[bobmichaels]

What difference does file size make? Other than you want it as small as possible given the print quality?

 

File size is primarilly a function of 8 bit vs. 16 bit, greyscale vs. color.

 

FWIW, the VERY BEST prints I ever made came from a 9 Mb file. It was an 8 bit greyscale file of an old 8x10 neg scanned on very high end equipment. I've scanned a lot of negs (35mm, 120, & 4x5) and made some very good prints. But nothing approaches that 9 Mb file for print quality.

[finepics]

I scanned my first 5x4 on my Epson 4870 using Vuescan at 4880 dpi and ended up with a 1.4gb file! Almost fried my PC. Detail was amazing though. My problem was that Vuescan chooses its own output dpi with the 4870 options and it selected 750 dpi (no option to change that until opening in PS). Downscaling in PS to 300 dpi gave a file of around 90mb.

[darin_young1]

Thanks all! Honestly, I wasn't quite sure how the math broke down with the dpi and all. But now that I know, I'll make some calculations.

<p>

Bob- I didn't quite understand what you were saying about the 9MB file. I won't argue that the print from that file was great. But usually doesn't a bigger file mean more detail and/or a bigger acceptable print size? If smaller files can do a better job than I'm all for it but how is it possible?

[steve_shames1]

Having scanned hundreds of slides on my Minolta Dimage at 2820 dpi, I can clearly state that at 8 bits, the file size is approx 27 megs, and at 16 bits, it is approx 54 megs. Of course if you crop in the scan a little, it will be less. This size of scan will usually give very good quality prints up to about 11 x 14.

 

I had some drum scans done at 5000 dpi, and that produced a 200 meg file at 16 bits (100 megs at 8 bits)

 

It took every ounce of energy from my computer to work on those 200 meg files.

[bobmichaels]

Darin: the point I was trying to make is that file size is just not a good metric. File size is influenced more by your choice of 8 bit vs 16 bit or RGB vs greyscale than it is by the number of pixels in the file.

 

And you only neeed a max number of pixels in the file to get you 300-360 in the print. Anything more than that is wasted. And printers are 8 bit devices. A 16 bit file is twice the size, and does minimize posterization with large photoshop adjustments, but end up being converted to 8 bit by the printer in the end.

 

So the basic concept of "a bigger file is better" just isn't correct. It needs to be big enough for the job but there is a point where you're just manipulating and saving bigger files to have most of the data thrown away in the printing process.

 

Many things ender into determining print quality. They include quality of the camera lens, film resolution, camera steadiness, scanner lens quality, true range of the scanner (limited by electronic noise NOT the published max), and having enough pixels in the file to avoid interpolation. But a bigger file is not one of them.

[bobmichaels]

I suggest www.scantips.com as a great reference to understanding the concept of file size / needed resolution.

[alexandru_petrescu]

Approx 220mb: vuescan, Minolta Elite 5400 (not the II), 16bit, raw, tiff, RGBI ("I" is the infrared channel).

<p>

Approx 1.2Gb: Imacon Flextight 949 the <a href="http://www.imacon.dk/sw3368.asp">manufacturer</a> says.