Scanning B&W positives?

[PeterAM]

Several years ago I read an article about the work of a photographer named Richard Lohmann; the article and looking at his web site stuck in my mind and I just dug it out. The article stated that he had medium format b&w negative film processed to produce transparencies because he got better results scanning from positives. If you were scanning either 645 or 6X7 on a flat bed like an Epson 700/750, would a positive be likely to produce a better scan than the negative?

 

[MikeSeb]

I'm not convinced this is true. He may be referring to the dr5 process, whereby just about any B&W film can be processed to transparencies. The DR5 people claim higher dynamic range in the positive than if the film were processed into a negative.

I can't confirm or refute this claim. If it's true, it might make some difference. But could a flatbed scanner actually capture this increased dynamic range? Doubtful.

 

[Jordan]

I'm with Michael on this one -- B&W positives may have finer grain than a negative from the same film, but they also have very high densities in the shadows that can be hard for scanners (especially consumer models) to dig into. No use having extra density range on your film if your scanner can't really see it.

 

[pellicle]

Hi

my feeling is that the Epsons scan better as positive, no matter if scanning positive or negative materials. For some reason this information has been widely discussed and conclusions reached by people with little supporting evidence used to base up arguments. Often the conclusion is to scan pos as pos and neg as neg because that's what the makers gave us and they know best ... right?

My primary argument is that scanning in positive I obtain better linear control of the scan process and scanning as negative it is hard to defeat the curves which are applied by the software. I feel this also applies to Nikon scanners.

For example in this blog post I make the points with this negative:

My experience in this is not simply mine nor is it unique. This article was written back in 2005. I can say that my experiments with Epson Scanners reveal similar issues and limitations.

As to weather negative or positive film has better tonal ranges you can find that out simply with some quick experiments. Using your scanner in positive mode for both you can conduct quick as a preview scan densitometry and see what tonal range exists on your exposure on your film:

and know where that sits with respect to your base film and your densest possible.

If you are interested, have a peek through the first part of this article of mine.

Essentially no matter if you are scanning negative or positive use your software as if you are scanning positive and you will get better control over your results and likely get more out of your materials.

 

[pellicle]

Mike

But could a flatbed scanner actually capture this increased dynamic range? Doubtful.

While it is true that a flatbed can not give the density of a drum, neither can Nikon's give much more.

I have made comparisons with my LS-4000, LS-IVED Epson 3200, 4870 and 4990 scanners with a Stouffer stepwedge

Please refer to this article on the LS-4000

meaning that its not worth probing in the darkness for more details. If any film is going to give better dynamic range then it will need to have a greater density range, with more available in the "thin areas" and less base fog. Regular black and white negative is pretty darn good if exposed and developed well

 

[cje2002]

Where I've seen this mentioned before I recall the argument has normally been that:

1) with a negative there is more density in the highlight areas of a print; whereas with a positive there is more density in the shadows.

2) greater density produces more grain, so negatives produce grainier highlights than positives; positives produce grainier shadows.

3) grain is more obvious in lighter areas; therefore a positive of the same scene is optimal in terms of distribution of grain

Please note that I am in way qualified to talk about this - I haven't ever even seen a b&w positive - but I think it's an interesting area for discussion.

Presumably you can control the contrast of a b&w positive by reducing dev time / temp / strength so that it would have a greater contrast range and thereby be more suitable for scanning (but less so for projection).

Finally I completely agree that scanning negatives as poitives generally leads to superior results.

Chris

 

[PeterAM]

I'm not convinced this is true. He may be referring to the dr5 process, whereby just about any B&W film can be processed to transparencies. The DR5 people claim higher dynamic range in the positive than if the film were processed into a negative.

I can't confirm or refute this claim. If it's true, it might make some difference. But could a flatbed scanner actually capture this increased dynamic range? Doubtful.

He was referring to dr5, which I have never heard of (just looked at their web site;very interesting). It would be interesting to know if anyone on here has used this process and what they think of the results.

I am shooting some film again (645, 6X7) and will be printing digitally. Needless to say, I'm thinking about a scanner but don't want to pay more than the cost of an Epson 700/750 plus software (if I can get adequate results, without devoting my life to the process). By adequate, I mean being able to print at least up to A3 size; I'll have a drum scan done if I want to go larger.

Also in that article was a comment that he combines two 6X7 scans to boost the resolution. Am I correct in assuming that this can be done with a straight side to side movement of the camera (allowing for X% of overlap) versus panning? Would love to know if anyone is doing this also.

 

[pellicle]

Peter

also for what its worth my scans of Provia vs Pro160C bring me towards the negative too

 

[cooltouch]

I've tried following Pellicle's advice, and scanned color negs as positives. My experience with my Epson 4990 is that colors are truer and more saturated, but grain is worse. I tried this using Kodak Gold 200 and Fuji Superia 400. I inverted the images and processed them in both Photo Shop and Paint Shop Pro, and got essentially the same results.

I haven't tried scanning B&W negs as positives. But I haven't really seen the need. My 4990 does a very good job scanning B&W so I don't see any reason to change the process.

 

[sanking]

I've tried following Pellicle's advice, and scanned color negs as positives. My experience with my Epson 4990 is that colors are truer and more saturated, but grain is worse. I tried this using Kodak Gold 200 and Fuji Superia 400. I inverted the images and processed them in both Photo Shop and Paint Shop Pro, and got essentially the same results.

I haven't tried scanning B&W negs as positives. But I haven't really seen the need. My 4990 does a very good job scanning B&W so I don't see any reason to change the process.

So long as you are sure that the scanner software is not clipping tones in either the shadows or highlights I don't think it makes an ounce of difference whether you scan as a negative or positive. Either way you can invert and then use curves and levels to adjust the image. So if you set the histogram to make sure that nothing is clipped you should be able to do it either way and eventually come out with the same result. The CCD and lens does not have a clue whether you have the software set to scan a positive or negative, it is just capturing raw data.

Sandy King

 

[pellicle]

Hi

I've tried following Pellicle's advice, and scanned color negs as positives. My experience with my Epson 4990 is that colors are truer and more saturated, but grain is worse.

glad you got some benefit from it. With respect to the noise, I've found that one needs to set the clipping points for red green and blue carefully. Much of what is called grain is channel noise (sorta like the stuff on the TV when you're off in no channel). As in my blog post.

this image shows how I've adjusted for the blue channel.

Then in photoshop (or your prefered editor) the use of some curves is also pretty needed to get the tones looking right. I find that adjusting them together is simplest first then tweaking each gradually later. I hold down the dark areas for a little bit and make the high areas taper off

however ... I think that I did find that Kodak was grainer than Fuji if I recall...

dunno ... mainly use Fuji ...heh

 

[cooltouch]

Thanks, Sandy, Pellicle. What you say certainly makes sense. I'll have to try this again, and make double sure that no clipping is going on -- pretty sure there isn't, but I'll check anyway.

I've also noticed that, after inverting, the color is almost totally washed out, now that I think about it. Seems like getting rid of the orange mask also ends up getting rid of most of the color also. But I countered this by punching up saturation -- a lot. Anyway, I'll give this another shot, and let y'all know of my results.

 

[sanking]

Are you scanning the color negative in RGB or Grayscale? If file size is not an issue I would recommend scanning in RGB and then convert in Photoshop with the B&W conversion. This will allow tremendous control of the tonal range of the negative. It will also allow you to use noise reduction in the individual channels.

Sandy King

Thanks, Sandy, Pellicle. What you say certainly makes sense. I'll have to try this again, and make double sure that no clipping is going on -- pretty sure there isn't, but I'll check anyway.

I've also noticed that, after inverting, the color is almost totally washed out, now that I think about it. Seems like getting rid of the orange mask also ends up getting rid of most of the color also. But I countered this by punching up saturation -- a lot. Anyway, I'll give this another shot, and let y'all know of my results.

 

[cooltouch]

Hey Sandy,

I scan my color negs in 24-bit RGB. I have an older copy of Photoshop -- v7 -- so I'm not sure I can do the B&W conversion, but I'll see. Not sure I'm following this anyway. What, are you converting the R, G, and B separately, then recombining? I'll have to check into this.

 

[pellicle]

I've also noticed that, after inverting, the color is almost totally washed out, now that I think about it. Seems like getting rid of the orange mask also ends up getting rid of most of the color also

thats why you need to then apply the curves ... after that try playing with the Hue for yellow first (not the saturation but the hue, its the top of the 3 sliders in the hue control in PS). It may need moving towards the red or the green depending. Often blue or Cyan needs tweaking too ... sometimes red needs shifting away from or towards yellow too

 

[mrred]

It would be interesting to know if anyone on here has used this process and what they think of the results.

I have not, but I met (presentation) someone who did. His "positives" are stunning. And yes, can only be drum scanned (for him, somewhere in calf) to extract the quality from them.

 

[sanking]

You can read about the dr5 chrome process by going to the web site.
http://www.dr5.com/

There are quite a number of tests comparing B&W film developed to a negative with traditional developers with the same film developed to a positive with dr5. The tests do appear to support the contention that one can get finer grain and better resolution developing B&W film to a positive, though some combinations of film/developer appear to closely approximate results with dr5.

However, my favorite B&W film is Fuji Acros and it is not included in the tests. Since I have been able to make 40" X 60" prints from Acros (120 film exposed in Mamiya 7II) developed in Pyrocat-HD with no visible grain and incredible sharpness I am convinced that in my case there is nothing to gain by having my film developed with dr5. There is also the considerable extra expense of the developing, plus the fact that in order to capture all of the shadow detail one would need to scan with a drum scanner.


Sandy King

 

[pellicle]

I'm a little with Sandy on this one ... when you consider the expense of the processing larger formats are always going to be better ... perhaps even though the Mamiya 7 is hard to beat going to 4x5 with a reasonable folding field camera (Toyo or some cheapie press cameras) and an OK optic will be hard to beat too

I mean, why get stuck on 35mm just cos in theory it can make the big enlargements ... you might find that per print you make the larger formats might be worth looking at ... although I appreciate why you may need 35mm for speed of operation and making many exposures.

 

[mrred]

I mean, why get stuck on 35mm just cos in theory it can make the big enlargements ... you might find that per print you make the larger formats might be worth looking at ... although I appreciate why you may need 35mm for speed of operation and making many exposures.

I agree. I have some MF (120) and I have shot nothing that I actually want to see that big. Technology is easy, content is another thing.....

 

[pellicle]

Hi

since there was some question about the details on what I do between scanning neg as positive and inverting I thought I'd put together this tutorial on my blog.

its only 5 steps, but they make a difference.

Hi

glad you got some benefit from it. With respect to the noise, I've found that one needs to set the clipping points for red green and blue carefully. Much of what is called grain is channel noise (sorta like the stuff on the TV when you're off in no channel). As in my blog post.

this image shows how I've adjusted for the blue channel.

Then in photoshop (or your prefered editor) the use of some curves is also pretty needed to get the tones looking right. I find that adjusting them together is simplest first then tweaking each gradually later. I hold down the dark areas for a little bit and make the high areas taper off

however ... I think that I did find that Kodak was grainer than Fuji if I recall...

dunno ... mainly use Fuji ...heh