Negative Vs Print Scanning

[whitworth photography]

I have always taken for granted that a negative has the ability to

produce a much higher quality scan than a print does. I was

discussing this with a friend a few days ago and he challenged this

belief. As an example, his take is that if you're scanning at the

same DPI and you've got a 4x6 print and a 35mm negative that was used

to create the print, that the print has more area to scan and thus

would produce more information (ie more inches=more dots).

 

I have tried to explain to him that a print is second generation

therefore cannot have the same quality. I was also thinking that the

materials the negative is made out of also have the ability to store

more data than the paper the print is made on can store.

 

I thought I'd run this by you guys to see if there is a better way to

explain why a scan from a negative is superior to a scan from a

print? I checked the archives, but couldn't find anything that

specifically addresses this. Thanks in advance.

 

Kirk

[Ed_Ingold]

Film scanning wins hands-down over scanning a a print. A print might have 2-1/2 stops dynamic range and 3-5 lppm resolution. For an 8x10 enlargement, that would translate to about 40 lppm on a negative - about 1/4 that of a film scanner. The dynamic range of a film scanner is between 5 and 7 stops.

[bruce_watson1]

<i>I have always taken for granted that a negative has the ability to produce a much higher quality scan than a print does.</i>

<p>

And you've been right.

[byronlawrence]

tell him that all he ends up with is WAY more information than he can use. you scan a print at 4000 ppi and you will just get nothing more than paper grain/texture. you can print that if you want I guess.

 

think of it as scanning a bill board. yea you get lots of info but is it worth anything?

[glen peterson]

If you are scanning a 4x6 print and a negative, both at 300 dpi...you could probably get more printable results from the 4x6. Above that The negative scans will win every time(in my opinion).

[conrad_hoffman]

It depends on what you have to scan with. If you have a flatbed and small negatives, then scanning a print may well be superior. If you have the best technology, like a film scanner, scanning the original will always be better than scanning a degraded copy (the print). The dynamic range of a print will never exceed 100:1 or so, usually less. Most negatives have more shadow and highlight detail than ever makes it onto the print.

[scott_eaton]

Feel free to have your friend scan a lustre surface print at 1200 dpi, and then compare it to a 1200 dpi scan from film.

 

The print will show very little detail because the textured durface diffuses it - badly.

[sean de merchant httpw]

Since your average minilab now scans and then prints at roughly 300 DPI you will not find much extra detail in a print by scanning at 4000 DPI. And what I have read is that optical prints only contain about 200 DPI worth of data.

 

Perhaps scanning a 20x30 print at 200 DPI might theoretically give you something comparable to a 4000 DPI scan if you disregard optical imperfections of the enlarging lens making the print soft. This also disregards dynamic range as already noted.

 

In the end, the amount of data in a negative exceeds that in a print. Otherwise you could not get a sharp 8x12 print from a 35 mm negative or a sharp 20x30 print from a top quality 35 mm negative (low grain film, mirror lock up, cable release, ...).

 

some thoughts,

 

Sean

[david_henderson]

Depends to an extent on your purpose. If I were scanning to make a display print then scanning the original film will be far better. But if I want to show people what my b&w fibre prints look like on a CD or via E-mail, then I scan the prints rather than scan the neg and try to replicate the darkroom process on screen.

 

That said, you should run your second paragraph past your friend again-maybe he'll get it this time.

[alexdi]

http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=006bzN

 

This was actually the first question I've asked here, back in 2003.

 

From a truly excellent print, you can pull about 85% of the detail. Colors and dynamic range suffer heavily. Most prints AREN'T well done though; standard photomat work has contrast jacked to the stops and tends to look blotchy.

 

The attached file is from a P&S 35mm body. What detail is in the print, my flatbed captured completely. The same probably can't be said for the negative.

 

DI<div></div>

[alexdi]

Cropped.<div></div>

[scott_kinkade]

I think the billboard analogy is excellent. Another way to put it is this: blowing up an image and then taking a picture of it cannot possibly give you more detail than the original, any more than turning up the volume on your CD player and recording it can give you more audio detail.

 

Of course, this assumes some relationship between the resolution of your scanner and the resolution of your enlarger...computations that I'm not qualified to make.

 

Also: David Indech...I did notice a perceptible loss of detail in BOTH of your samples, in the area above your subject's shoulders.

[alexdi]

Scott:

 

These samples are primarly to illustrate the loss of shadow detail. The cropped subject is well removed from the focus point.

 

DI

[ross_lipman]

What about downscaling ? Going from a print size of 8.5 x 11 to say 5x7 or 4x6 ?

 

Other than color caste (correctable through digital processing), wouldn't the final print be virtually indistinguishable from a print of the same size derived from a negative ?

 

Thanks,

 

Ross

[Ed_Ingold]

I should have prefaced my previous remarks by stating that the best film scans greatly exceed the quality of the best print scans. I failed to notice the artificial constraint you placed in your question "at the same resolution..."

 

Fuji Frontier prints are approximately 300 dpi, regardless of size. The quality of a print scan will not improve if the scanner resolution exceeds this value. For a 4x6 enlargement from 35mm, this is equivalent to 1200 dpi at the film. Broadly speaking then, you will get sharper results scanning a 4x6 print than film if the resolution is less than 1200 dpi. The color and dynamic range would still be better from the negative (only if you scanner can deliver the goods).

 

That begs the question, "Why would you scan a negative at such low resolution?" A 4000 dpi, 14-bit/channel film scanner extracts about as much useful information as possible (short of true grain-sharpness). Making the comparison using a flatbed scanner (the best consumer flatbed has an effective resolution of about 1500 dpi) is limited by the hardware not the media. So which is better, to be blind in the right eye or blind in the left eye?

[scott_kinkade]

David...

 

I was referring to the "loss of detail" in the facial area...ie your privacy blurring. A little Thursday morning humor.

 

Cheers...

[whitworth photography]

Thanks for all of your responses. There is some good information, analogies and examples here that I'm going to try to put into an email to see if I can better explain the difference to my friend.

[alexdi]

Sorry Scott.. that post was an AM diversion from the all-nighter I pulled for an exam this afternoon. Sense of humor is temporarily paralysed..

 

Dave