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05-19-2017, 12:35 PM   #1
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What quality scan for very large prints of 120 film?

Hi, Team,

I recently got into medium format film with the intention of being able to produce very large prints (like 30x40in images) that are beautifully sharp. I want to take portraits and landscapes, primarily. Of course I chose a Pentax 67 to help me accomplish that goal.

Provided everything with the exposure is spot on, what quality of a scan will I need to produce prints that large?

Before I researched the topic, I presumed that I could buy a scanner for a few hundred dollars to help me get the image quality I need out of my 120 film. I now think I was dead wrong. It looks like I will need to spend over $1000 to buy a scanner with that type or resolution.

I have a Canon 70D and a Canon Pixma Pro 100 that produces fantastic images together around 13x19 in. The whole reason I bought my Pentax system was to outclass the image quality I can already achieve dramatically.

So it looks like I may buy an Epson Photo model for every-day work, and end up scanning and printing my very large prints at a service. Please correct me if I am missing some fantastic budget option.

The Find Lab, for example, can scan 120 film in various resolutions. Anywhere from 3100x2475 px for $10 to 5994x4800 px for $17. These prices are for basic scans with no in-lab processing.

http://thefindlab.com/pricing-2/

What level resolution will I need to create very large prints? Does anyone have any suggestions for achieving these results inexpensively? Am I crazy? Should I sell all my gear and just go back to digital photography? :P

Thanks for your thoughts!

05-19-2017, 12:59 PM   #2
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Well, I have a Nikon 9000ED with almost a true 4000dpi resolution. A full 6x7 negative scan gets me a little over 10000 pixels in the longest dimension. So I can do 16x20 prints at 300dpi. And that is my usual size I do.

High-end scanners also grab more density off your film too for better tonal scale than commodity scanners. So its more than resolution that is important.
05-19-2017, 01:08 PM   #3
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If you your goal is to match the resolution of the 20 MPix 70D images printed on 13x19, a bit of math says you want about 280 pixels/inch. Thus you'll want about 8400 x 11200 which is a 94 MPix scan to get a good 30x40.

The cheapest solution would be to use your 70D with a macro lens and take maybe a 2x3 or 3x3 tile "scan" of each film image and stitch the tiles together. But it's very labor intensive.

The Find Lab option does not sound very good. It's only 28 MPix which isn't that much higher a resolution than your 70D.
05-19-2017, 01:28 PM - 1 Like   #4
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All scanners similar to digital cameras (Bayer array) are not able to truly resolve anywhere near their claimed optical resolution. In the case of Epson flatbed scanners with an optical resolution of 6400 SPI(DPI) quoted while 6400 pixels per inch is true the scanner can only truly resolve detail equating to between 1500-2300 ppi depending on model. Exceptions to this would be Nikon film scanners that while they cannot resolve at the quoted SPI come very close in comparison to flatbed reaching maybe 3500 SPI out of the quoted. Dmax on these flatbeds quoted as above the theoretical max of 4.0 reserved for top of the range models while lower priced may get Dmax 3.4?

Nikon scanners are as rare as rocking horse err, droppings, at least at what I consider reasonable prices. A company called Plustek do make dedicated film scanners, but I think it fair to say that they will not be in the same league as Nikon.

Drum scanning usually the top albeit pricey option. Hiowever with a macro lens on a DSLR capable of 2:1 or more and a little ingenuity and time stitching copy images could result in results better than other scanning methods? Perhaps best reserved for hero images?
Edit. Pipped at the post by photoptomist

05-19-2017, 01:33 PM   #5
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QuoteOriginally posted by photoptimist Quote
If you your goal is to match the resolution of the 20 MPix 70D images printed on 13x19, a bit of math says you want about 280 pixels/inch. Thus you'll want about 8400 x 11200 which is a 94 MPix scan to get a good 30x40.

The cheapest solution would be to use your 70D with a macro lens and take maybe a 2x3 or 3x3 tile "scan" of each film image and stitch the tiles together. But it's very labor intensive.

The Find Lab option does not sound very good. It's only 28 MPix which isn't that much higher a resolution than your 70D.
Any suggestions for labs that could render a 40+MP image? I'm not sure how much more detail then that is extractable from a 120 negative. What is the limit?

Optimist, you raise a really good point about taking many macro shots of a negative. I never thought about doing that. I just assumed that if you "scanned" with a DSLR you'd only get as much detail as your sensor, but by taking a few or several images you could triple your detail. Hypothetically.

If I can get amazing results that way for free I will definitely do it. I don't care if it takes me a few hours to produce the image "scan." I already have a Canon 100mm macro lens.
05-19-2017, 01:51 PM - 1 Like   #6
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Forgot to add these as I believe you will find them if great interest in your new venture

Why You Should Digitize Your Film Using a Camera Instead of a Scanner

How to Scan Your Film Using a Digital Camera and Macro Lens
05-19-2017, 02:21 PM   #7
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QuoteOriginally posted by TonyW Quote
Forgot to add these as I believe you will find them if great interest in your new venture

Why You Should Digitize Your Film Using a Camera Instead of a Scanner

How to Scan Your Film Using a Digital Camera and Macro Lens
Tony, this is nothing short of game changing. You just saved me from being really bummed about the prospect of spending hundreds on scans or thousands on scanners. I'm the type of person who loves to fiddle with stuff like this too, so I think I have it in me to do it (although 28 shots seems like a LOT of macro photos one one negative... ahh well. Its all for the sharpness!

I was under the impression that a 6x7 negative would have MAYBE 60MP worth of detail in it. 6 shots with my Canon 70D represents probably 120MP worth of detail! Now, rendered through the macro lens, it probably only resolves 10MP of perceptual megapixels per shot... so maybe 60MP worth of detail is a realistic resolution estimate.

Lord! Has anyone written a really nerdy report or crunched the numbers on how much detail you can get from a 6x7, especially with using this method?
05-19-2017, 02:39 PM   #8
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Here's one analysis of the detail from a 6x7 vs. digital.

Comparing the Image Quality of Film and Digital

05-19-2017, 02:44 PM   #9
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I've always wondered about dynamic range in digital camera scans. Remember, the advertised DR of a digital camera is Engineering DR (SNR 1:1) and not photographer's DR like you'd measure and capture on film with a one-degree spot meter. So you have to subtract 2 to 3 stops of DR from that advertised to realize what you typically work with. So are you grabbing all the tonal scale that's on the negative? I don't don't know.

But Drum scanners do a very good job of getting beautiful tonal scale especially in sheet film which you can send out to get done for those really big prints you want.
05-19-2017, 02:48 PM   #10
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QuoteOriginally posted by photoptimist Quote
If you your goal is to match the resolution of the 20 MPix 70D images printed on 13x19, a bit of math says you want about 280 pixels/inch. Thus you'll want about 8400 x 11200 which is a 94 MPix scan to get a good 30x40.
If you want to look at actual scanning, and going along the lines of these numbers -- I have 35mm negatives scanned by a Flextight X5 scanner which are about 7000 dpi. That resolution would give you a 19000 x 16000 scan , which would be more than enough to print at 30x40 inches. Not sure of the relative actual resolution you get for that vs. DSLR "scanning", but maybe play around a bit and see what works for you. (The current Flextight does 8000 dpi, according to the web.)

I have also printed photos at 150-200 dpi resolution and those look quite good, as well.

---------- Post added 05-19-17 at 02:50 PM ----------

QuoteOriginally posted by tuco Quote
I've always wondered about dynamic range in digital camera scans. Remember, the advertised DR of a digital camera is Engineering DR (SNR 1:1) and not photographer's DR like you'd measure and capture on film with a one-degree spot meter. So you have to subtract 2 to 3 stops of DR from that advertised to realize what you typically work with. So are you grabbing all the tonal scale that's on the negative? I don't don't know. Drum scanners do a very good job of getting beautiful tonal scale especially in sheet film which you can send out to get done for those really big prints you want.
When you get a scan, I'm not sure if you get the full range of what the negative holds. Could you do an "HDR"-style scan where you do a couple scans at different illumination, and then combine them to get extended DR and highlight recovery? Or do you get the full range of the negative in just one single-pass scan?
05-19-2017, 03:00 PM   #11
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QuoteOriginally posted by leekil Quote
... I have 35mm negatives scanned by a Flextight X5 scanner which are about 7000 dpi.

When you get a scan, I'm not sure if you get the full range of what the negative holds.
I believe the X5 doesn't do 7000dpi for 6x7 negatives. But, yeah, that's the challenge of scanning is to get all that you can from the negative. And drum scanners are among the ones that grab the most density.

My 9000ED only does okay. It doesn't reach deep into the blacks as I'd like. It just clips them at some point. That's why I think for scanning one should add more exposure if you want to get more dark tones.
05-19-2017, 04:19 PM   #12
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QuoteOriginally posted by tuco Quote
I've always wondered about dynamic range in digital camera scans. Remember, the advertised DR of a digital camera is Engineering DR (SNR 1:1) and not photographer's DR like you'd measure and capture on film with a one-degree spot meter. So you have to subtract 2 to 3 stops of DR from that advertised to realize what you typically work with. So are you grabbing all the tonal scale that's on the negative? ...t.
I agree as we often see things like 14+ stop DR when the max cannot be any more than the bit depth then must loose some due to noise.

That's where people like Bill Claff come to the rescue with IMO a truer look at things such as DR with his Photographic Dynamic range. My own testing of a camera touted as having 14 stop range came in at 11.7 stops his testing coming in close with multiple samples. Therefore I tend to trust his judgement on these matters
An example
Photographic Dynamic Range versus ISO Setting

In many cases a DR of 12 EV will be more than adequate to capture the tonal scale and if not combining multi images should take care of the rest. At least that is my feeling without really trying this
05-19-2017, 07:26 PM   #13
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The key to quality scans is a competent optical path and accurate focus of the negative to the scanner array. As noted above, with larger negatives one does not need high resolution scans to support large prints.
  • Work backward from the print size you want
  • Determine the pixel dimensions you need to support the print resolution you want without upsampling.
  • Scan to satisfy those pixel dimensions. Here is a rough example:
    • Printing at greater than 300 dpi is a waste of ink so we will use that print resolution for "best quality"
    • For a 25"x30" print from a 6x7 negative that would be 7800px across the short axis, allowing for a mild crop on that dimension
    • Assuming that short side is actually 6cm(2.36"), a scan resolution of 3300 dpi (7800/2.36) should work well
    • In the real world, one would could reasonably use 200 dpi for that large a print, bringing the required resolution well withing the capabilities of the better flat-bed photo scanners
I use an Epson V700 for my 120 film scans and find that its real world resolution of ~2400 dpi is quite adequate. If one needs more, the better dedicated 120 film scanners will provide higher resolutions. A commercial reprographics service may also be an option.


Steve
05-20-2017, 05:15 PM   #14
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QuoteOriginally posted by Femto1969 Quote
Provided everything with the exposure is spot on, what quality of a scan will I need to produce prints that large?

. . .

What level resolution will I need to create very large prints? Does anyone have any suggestions for achieving these results inexpensively? Am I crazy? Should I sell all my gear and just go back to digital photography? :P
What kinds of films are you using - planning to use?
05-21-2017, 03:48 PM   #15
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From the perspective of having made 36" wide prints from 6x7 (have 44" hp Z3100 and Screen DT-S1045AI) I found them slightly disappointing in terms of sharpness if you really want sharp and very large prints larger formats are really the answer.

I personally found the V750 inadequate for what I wanted and would generally scan 120 at 4800dpi as the maximum non headache resolution on the Screen for 6x7 although I would also regard that as beginning to reach as to what is available from most fine grained films.

It all kinda depends on peoples personal perspective on what they consider sharp and up front I'll point out that I regard viewing distance as applicable to advertising posters I want a print to be pin sharp from say one to two foot away not six feet.

As to prices of scanners it is possible to pick up Drumscanners for prices in the hundreds of dollars sometimes you just needed to be able to cope with generally the evils of Mac OS9 and obscure SSCI settings and the need to repair them yourself (mine is currently sulking sadly) I also see the Pro flat beds going for silly money these days too mostly the same caveats as drum scanners they are usually a bit smaller though well at least not the upright piano size and weight of the screen.

edit

What you want to achieve will not be inexpensive, if you want relatively inexpensive you are going to need to do everything yourself for the sort of scans you need bureau prices would soon mount up but then it will be the same for printing if you actually want to do this have a look into what real pro scanners sell for secondhand and think about getting your own large format printer they are way cheaper to run in the long run as the larger ink cartridges are proportionally far cheaper than the A3+ machines they do take up a lot of room though.....

The Screen is hiding behind the printer and the other drum scanner on the bench is a Collogetter Pro II that was won for 123 only 8bit software though.

If you do consider the insane but cheaper do it all yourself route really make sure you do your research about the various limitations and pit falls of all the various hardware.




Last edited by ABBANDON; 05-21-2017 at 04:02 PM. Reason: extra detail
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