Influence of Film on scanning

[deFocused]

I wonder if anyone tought about the following:

The film base of films is different from one film to other. Some are more transparent than others. Do you think this has influence in the way films are scanned?

It seems to me that the more transparent the film base the more accurate and more information we can get from a scan.

Does this make sense? Am I missing something?

 

[Ash]

It's been discussed before, I'm positive.

When you scan a film with a dense base, it requires more light to pick up detail, and the scanner doesn't usually like that.

I've found I get more noise in the image from these kind of negs. Some sites recommend certain films specifically for scanning, because the thin base is easier to deal with.

I can't remember if this is correct, but someone recommended to over-expose and under-develop I think??

I may be totally wrong, but that's what I remember reading. Also when you scan, you can choose where on the histogram to scan, so most of the 'accuracy' is decided by you, and what you want from the neg.

 

[deFocused]

"When you scan a film with a dense base, it requires more light to pick up detail, and the scanner doesn't usually like that."

Do the scanners use this? I think they use always the same light.


"I may be totally wrong, but that's what I remember reading. Also when you scan, you can choose where on the histogram to scan, so most of the 'accuracy' is decided by you, and what you want from the neg."

Well, but that is only a post-processing issue. You are not getting more detail/information from the area in the histogram you decided to scan. I think....

 

[Ash]

When I use the scanning software with the Epson Stylus RX500 plugged into photoshop, I can alter how the image is scanned. The light does not change its brightness, but the scanner adjusts its light intake. That's my guess. Otherwise how would it pick up the extra details?

 

[estepan99]

Hi!

I even noticed a big difference in the developer used:
Some years ago I shot a Delta 3200 which I developed in ID11/D76 when I recall correctely, last weak I developed one in Amaloco AM74, which is supposed to be a fine grain developer.
The difference is night and day, where AM74 is night, deep, dark night!
The negs are so bad (for the Epson 4180-Scanner) that the scanned pics are nearly unusable. I don´t know how they will look like when enlarged wet. Surely better.
The old negs deved in ID11 are really awsome!

Greets, Stephan

 

[bmicklea]

I've noticed this yes. With my Nikon Coolscan I can vary the brightness of the LEDs to compensate but I do seem to lose some tonality (contrast compression). The best films to scan in my experience are the Ilford Delta films because of their relatively thin base. For this reason they've started to become my standard films.

Unexposed negs do seem to work better in the scanner than overexposed.

 

[Ash]

Unexposed negs do seem to work better in the scanner than overexposed.

That's funny... I would have thought an unexposed neg would come up blank? 😀

 

[photogdave]

Rollei is marketing some new C41 colour neg films with a clear base designed for scanning. I hope to shoot a roll soon and post the results.

 

[Sparrow]

Just a general observation, I can never be bothered to test these things properly, but I’ve noticed with Fuji 400 superia I have less work to do to get what I want, nothing scientific it just seem to suit the scanner

 

[charjohncarter]

I have had to reduce my development times and agitation from earlier enlarger days negatives to get a more full tone scan. This has been a real pain because I have also had to cut the ISO to get good scanning shadow detail. The pain is retesting everything with little or no starting point.

 

[deFocused]

I have had to reduce my development times and agitation from earlier enlarger days negatives to get a more full tone scan. This has been a real pain because I have also had to cut the ISO to get good scanning shadow detail. The pain is retesting everything with little or no starting point.

Exactly the same conclusions that I am reaching...
And if you need to make a normal print is the negative usable?

Did you noticed any adavantage in films with a clear base regarding scanning. I have found that Fuji Acros is much more easy to handle that Delta for instance because the base is more transparent for the scanner (or maybe I am making something wrong).

 

[thafred]

HI, I´ve shot and scanned some of rollei/Maco´s films and they all had a clear PE base (cristal clear base much like tesa-film) wich helped scanning quite a bit I think.

AFAIK the denser the Base the more compressed is the tonal range captured by the scanner.
I think of it like this (simplified) for a clear base we assume the value 0 (zero) for max. density the scanner captures the value is 100 so 100steps between clear and dense (black n white)..if the Neg has a very gray base (HP5 or APX400 for example) you logicaly have a compressed range since it starts at a value of say 20 and ends at the scanners D-Max of 100 so only 80 steps in between.

I have one test roll of Rollei Scan Film 400 in my fridge but havent used it yet. looking forward to try scanning color neg´s without orange mask and on PE base 🙂

 

[charjohncarter]

deFocused, A normal print is possible, you might as in my case bump the contrast of the paper up. Which to me is easier than playing around with a scanner. I haven't noticed the film base having anything to do with the scans as I have been using only Tri-X and Plus-X. After I get this scanning mess straightened out I might branch out to other films. thafred said the Rollei/Maco base is very clear. That sounds like a good start.

 

[deFocused]

deFocused, A normal print is possible, you might as in my case bump the contrast of the paper up. Which to me is easier than playing around with a scanner. I haven't noticed the film base having anything to do with the scans as I have been using only Tri-X and Plus-X. After I get this scanning mess straightened out I might branch out to other films. thafred said the Rollei/Maco base is very clear. That sounds like a good start.

I have tried with Fuji Acros and Delta 400 and the scanner "notices" something like 2 stop (guessing) difference between the 2 films, being Acros the clear one, allowing much better tone capture from the scanner.
Anyway I must make much more tests...

 

[stevierose]

I find that choosing a film and development process that favors retaining a longer tonal range leads to better scans. The negative then holds all the tones, I scan it "flat" to capture the whole tonal range, and then use post-processing curves to adjust contrast to taste. I also find that overexposing and "underdeveloping" by around 10-15% helps accomplish these goals. For these reasons I like HP5+ for this purpose--some complain that it is too low contrast and comes out with a bunch of "blah" grays, but I find that when shot, developed, and scanned in this way it is pretty ideal for BW.

 

[agentlossing]

I find that choosing a film and development process that favors retaining a longer tonal range leads to better scans. The negative then holds all the tones, I scan it "flat" to capture the whole tonal range, and then use post-processing curves to adjust contrast to taste. I also find that overexposing and "underdeveloping" by around 10-15% helps accomplish these goals. For these reasons I like HP5+ for this purpose--some complain that it is too low contrast and comes out with a bunch of "blah" grays, but I find that when shot, developed, and scanned in this way it is pretty ideal for BW.

This is what I have been doing as well, more or less. Do you feel like the scans with lots of tonal range need a significant amount of editing? I have alternated between adjusting exposure, contrast, individual levels and structure and simply applying a built-in Lightroom B&W preset to achieve a decent look.

 

[charjohncarter]

I find that choosing a film and development process that favors retaining a longer tonal range leads to better scans. The negative then holds all the tones, I scan it "flat" to capture the whole tonal range, and then use post-processing curves to adjust contrast to taste. I also find that overexposing and "underdeveloping" by around 10-15% helps accomplish these goals. For these reasons I like HP5+ for this purpose--some complain that it is too low contrast and comes out with a bunch of "blah" grays, but I find that when shot, developed, and scanned in this way it is pretty ideal for BW.

I do this too. I give in pro mode some extra room below black and above white. The I use levels to 'sneak up' on my final file. I also overexpose my films.

Tmax 100 expired HC-110h by John Carter, on Flickr

 

[Freakscene]

 

[willie_901]

"When you scan a film with a dense base, it requires more light to pick up detail, and the scanner doesn't usually like that."

Do the scanners use this? I think they use always the same light.


"I may be totally wrong, but that's what I remember reading. Also when you scan, you can choose where on the histogram to scan, so most of the 'accuracy' is decided by you, and what you want from the neg."

Well, but that is only a post-processing issue. You are not getting more detail/information from the area in the histogram you decided to scan. I think....

Film physical properties profoundly affect scanning results. Most scanners use a fixed amount of illumination. This is the reason why differences in films occur.

The scanner light color temperature is also relevant as different films could respond differently to light with different color temperatures. LED scanners deliver more constant light over their lifetime as the bulb characteristics are less affected by aging.

To simplify the discussion let's think about transparency film.

Suppose the scanner light illumination is insufficient to adequately represent (model) the shadow regions in film with a dense base. Information from the unilluminated film regions is not present in the data. No amount of post-production trickery can recover data that never existed.

The scan histogram means nothing. No setting can add data that was never collected! A nice looking histogram only describes the information content that was digitized. [1] Information lost by inadequately lighting the source is not present; can not be known; and can not be recovered.

However, the exact same scene using film with a thinner base will pass more light which increases the overall information content.

For these reasons this why optimum exposure and development decisions for film that will be scanned can be different for film that will be printed using a pure analog process.

1. This is also the motivation for using scans that generate raw data. No information is lost due to lossy JPEG or TIFF compression. No information is lost due to non-optimum, but well meant, JPEG or TIFF rendering parameters. A fundamental tenement of information theory is to retain as much data as possible. Scanning with compression and rendering parameters applied destroys some of the original data. In some cases the lost data in uninformative. This is not always so. The time to discard uninformative data is during rendering of the raw scanner data. Some scanner software supports the generation of flat demosaicked data. The data can be in TIFF or DNG format. In both cases irreversible changes in the original data due to applying \ demoasicking parameters such as white balance, relative channel scaling (contrast and curves) and sharpening during scanning are avoided. Instead image rendering is optimized during post-scanning rendering.