developing B&W to positive for scanning?

[PhilBurton]

In a different forum there is now a discussion about developing B&W to a positive instead of to a negative. Does anyone have any experience scanning B&W positives? How does that compare with scanning B&W negatives? Does it matter?

Phil Burton

 

[George Collier]

I've scanned color transparencies and black and white neg film, and I don't see any difference, apart from scan software settings to achieve the right tonality.
You can even reverse in Pshop if you have to.
I would go with which ever method you have the most control over to produce the film - neg or positive.

 

[removed account4]

hi Phil

There used to be an active member here from the UK named Gavin (https://www.photrio.com/forum/media/users/coigach.12928/) who used to send a lot of his film to DR5Chrome to be processed into positives. You can search through his posts and gallery uploads to see what he he did and why. It was a part of what he did and he did it very well.

 

[Lachlan Young]

Does anyone have any experience scanning B&W positives?

Yes, quite a lot. Not any more or less difficult than negatives or colour transparencies.

How does that compare with scanning B&W negatives?

They aren't as good, for much the same reasons that transparencies aren't as capable as negatives - if the scanning/ inversion stages of the negs are done competently. If you're viewing the transparency as the final object, that's slightly different from scanning it in terms of the sharpness requirements etc. I personally quite like the tonality of some films processed as transparency in the Scala process (Delta 400 in 120), so I'm prepared to accept the lower sharpness and coarser granularity.

I've attached a very quickly edited/ superimposed representation of the official Agfa MTF curves' differences between what was essentially the same emulsion processed as a negative (Agfapan APX 100 - the black line) and as a transparency in an optimised process (Agfa Scala 200x - the grey line). The point that matters for getting really critically sharp images in reproduction is where the 50% MTF response is. The RMS grain of APX 100 was 9.0, of Scala 200x, 11.0 - enough difference to be noticeable.

 

[runswithsizzers]

First, if you plan on reversal processing, I would recommend exposing b&w positive film more like color slide film than negative film. That is, I think exposing positive film requires more accuracy and more protection of the highlights, compared to negative film. Also, be aware the same film may benefit from a different exposure indexes, depending on whether you plan to process it as a negative or positive.

The higher D-max of some B&W positives can be a problem for those scanners that are not good at getting details from deep shadows. It's been a while since I scanned any positive film, but as I recall, trying to pull down the highlights often resulted in a lot of what looked like coarse grain, but was more likely an artifact of the scanning process. I had much better luck getting detail from deep shadows IF my scanner was able to see them. Obviously, you will want to scan as 16-bit TIFFs or DNG or something with more capability than 8-bit JPEGs.

I have some results of b&w positive film that I have scanned you can look at if you click on the links, below. Keep in mind, my posted images have got a fair amount of post-processing, so not sure they will tell you that much.
Ilford Delta 400
Ilford HP5 Plus
Adox Scala 160
Kodak T-Max 100
Fomapan-R

 

[Les Sarile]

As it pertains to scanning, if b&w is processed as a positive, will IR cleaning (dust & scratch removal) work with it?

 

[Lachlan Young]

As it pertains to scanning, if b&w is processed as a positive, will IR cleaning (dust & scratch removal) work with it?

No, there's no removal of the silver image.

 

[PhilBurton]

Thanks to all who replied. It seems that there is no compelling reason to process B&W for scanning to a positive image for scanning, as opposed to traditional processing. I appreciate all these points.

That's why I subscribe to Photrio.

 

[Adrian Bacon]

In a different forum there is now a discussion about developing B&W to a positive instead of to a negative. Does anyone have any experience scanning B&W positives? How does that compare with scanning B&W negatives? Does it matter?

Phil Burton

For black and white, if you’re scanning with a 14-16 bit scanner, it just doesn’t matter.

 

[MattKing]

In addition to scanning, do you darkroom print, or project your photos?
If the answer is yes to either of those questions, that will also answer the "what should I do" question in this thread.

 

[Lachlan Young]

First, if you plan on reversal processing, I would recommend exposing b&w positive film more like color slide film than negative film. That is, I think exposing positive film requires more accuracy and more protection of the highlights, compared to negative film. Also, be aware the same film may benefit from a different exposure indexes, depending on whether you plan to process it as a negative or positive.

The higher D-max of some B&W positives can be a problem for those scanners that are not good at getting details from deep shadows. It's been a while since I scanned any positive film, but as I recall, trying to pull down the highlights often resulted in a lot of what looked like coarse grain, but was more likely an artifact of the scanning process. I had much better luck getting detail from deep shadows IF my scanner was able to see them. Obviously, you will want to scan as 16-bit TIFFs or DNG or something with more capability than 8-bit JPEGs.

I have some results of b&w positive film that I have scanned you can look at if you click on the links, below. Keep in mind, my posted images have got a fair amount of post-processing, so not sure they will tell you that much.
Ilford Delta 400
Ilford HP5 Plus
Adox Scala 160
Kodak T-Max 100
Fomapan-R

Those images look very noisy/ grainy in the highlights - it may be an artefact of the scanner/ post processing, but they are noticeably worse than what I've seen from several of the same films run in the Scala process & which I've scanned on a Hasselblad/ Flextight up to 6300ppi.

 

[runswithsizzers]

Those images look very noisy/ grainy in the highlights - it may be an artefact of the scanner/ post processing, but they are noticeably worse than what I've seen from several of the same films run in the Scala process & which I've scanned on a Hasselblad/ Flextight up to 6300ppi.

I agree, many have objectionable noise in the highlights. I'm pretty sure that is due to a combination of the way my old scanner read the files, and the way I post-processed them. I now use a mirrorless camera and a repro lens to digitize film - I should re-work some of those b&w slides to see if my new methods can produce cleaner results.

 

[Lachlan Young]

I agree, many have objectionable noise in the highlights. I'm pretty sure that is due to a combination of the way my old scanner read the files, and the way I post-processed them. I now use a mirrorless camera and a repro lens to digitize film - I should re-work some of those b&w slides to see if my new methods can produce cleaner results.

I can probably fairly quickly dig up some Silvermax/ Scala 160 in 135 and Delta 400 in 120 scans if those are of use as comparators.

 

[Raghu Kuvempunagar]

There used to be an active member here from the UK named Gavin (https://www.photrio.com/forum/media/users/coigach.12928/) who used to send a lot of his film to DR5Chrome to be processed into positives.

Very nice and inspiring work! If these scans are any indication, it must be a wonderful visual treat to see these DR5 processed slides projected.

 

[destroya]

i have scanned many B&W slides that i develop in a home brew formula and the results are great. but they are not that different than a traditional neg shot. the developing process is much more complicated with reversal, so take that into consideration.

if you are just scanning, I would stick to developing to a neg. this gives you the option of wet printing as well. But I do love projecting B&W slides. if you are going to do slides, use a film like foma 100, or the rollei retro films as they have a totally clear base and that really makes the slides pop

john