Matching Film Curves to Scanners and devices

[Jeffrey Sipress]

I scan both color 4x5 transparencies and B&W negs on my flatbed scanner. I have a fully endowed and color managed imaging workstation. Recently, while discussing the varying degrees of scanning success with an associate, we both noted that some pieces of film just scanned better than others, without requiring the numerous repeated adjustments of every conceivable software menu control and the constant fighting with the thing just to get a half decent result. He suggested that perhaps the tonal curve and the dynamic range of a particular exposure more closely matched that of the device, the scanner in this case. So, we thought that the 5 stop range of velvia, for example, better matched the scanners range, and that trying to get a beautiful 10 stop range B&W neg to give us all it had was a futile effort. The question arose..... what is the scanner's range in stops? Is this even a measurable value? Is that what Dmax means? Seems to me that if your scanner's range matches that of your film, and your software and monitor's range equals or exceeds that value (which they usually will), then things will go better. Perhaps scanning color trannies and converting to B&W in PS will give me better results than trying to scan a full scale neg. So, I picked up one of those long B&W test charts from Kodak (in the long yellow cardboard sleeve) and am about to scan it to see what the scanner (4870) will do. The chart has 20 increments from W to B each being a third stop, I believe.

Perhaps that's why Kurt suggests using Fuji NPL color neg film for B&W conversion for better results. Has he matched his curves?

Has anyone here already done this?

[Kirk Gittings]

I think I am the Kurt you are talking about. I guess the answer is not really. I have profiled my scanner with an IT8 transparency target but............I scan negs unclipped so the dynamic range of my neg. scan is unrelated to the profiles. When I first bring it into PS it looks a little flat anf lifeless but with rich detail way down into the deep shadows and bright highlights. I want full information to start with. I may discard it later as an aesthetic choice, but at the start I want more information than what I end up with.

I am not trying to reproduce a scene or a piece of film in my final prints. My prints are about how I feel about a place rather than how a place looks. The scan is simply a starting point and the more that is there the more choices I have in the creative process of making an expressive print. I. E. I don't want my scan to match the original scene or the dynamic range of my output. I want to have as much plasticity in the process as possible.

[Brian Sims]

I agree with Kirk--the scan should leave you with the greatest amount of information (resolution, dmax, color depth) that you can transfer from your film. After 30 years shooting film & 2 years with digital, I am convinced that, for the foreseable future, having one foot in the old and one foot in the new leads to the greatest satisfaction. Shooting film still beats digital capture. Digital printing has finally caught up with photographic printing (and is still on a steep innovation curve). The weak link is in the scan. I've been using the 4870 for about a year. With enough work, I was getting good results. But I was leaving info behind on the film. Tonal range was short and choppy compared to going directly from film to photographic prints. I tested my best 4870 scan with a $60 drum scan from a commercial printer (using a 10 year old scanner). With the drum scan, resolution was crisper in certain parts of the image, and shadow and highlight detail was better. More importantly, there was a noticeably smoother transition across the tonal range. So given that sometimes I spend days hiking into the wilderness and hours composing a couple of shots, and I don't spend money gambling, drinking (much), or womanizing (beyond general flirting), I just ordered the Imacon 646. Now I just have to find enough film photographer friends who want high quality scans to convince the IRS and, more importantly, my wife that this was a business expense. I'll share the results as soon as I get the machine.

[Henry Ambrose]

In an ideal sense, your film should contain a range of densities that matches your scanner's range (much like making a piece of film that matches your darkroom paper's reproduction capabilites). Manufacturer's specs will not answer the question of the range of your scanner but a few trials will. Scanning the step wedge will tell you a lot about your scanner's capability.

The idea is to never leave out (in histogram language, "clip") any info in scanning. After you get the scene info into your computer you are free to interpret it as you see fit. If its not there, you can't. The reason to shoot color neg film instead of tranparency fim is that color neg has the ability to capture a wider scene range.

[Ellen Stoune Duralia]

"The idea is to never leave out (in histogram language, "clip") any info in scanning."

I've read that alot and I think I kind of get it but I'm also still a little confused. It's such a fundamental concept; I'd like to understand it fully. How do you know when you're "clipping"? I'm using SilverFast AI - could you explain exactly what settings I should use/change in order to make sure I'm not "clipping". Thanks!

[Jeffrey Sipress]

Yes, Kirk, you. Imagine my embarrasment!

So it seems that you gentlemen, and maybe Ellen, are not worried about the exactness of the ideas I presented. That's great, because I'm not really there (yet!) myself, and I generally follow the same approach as you. But like Brian says, who wants to leave info on the film? What I was after is a greater degree of control over the full tonal ranges on the film, if it ever gets into my computer.

Yes, Kirk, you want full info to start with. We all do. But no one has addressed whether their scanner is giving them the 'full info'? Wouldn't you all want to know that?

[Kirk Gittings]

Jeffery,

I spent many years fine tuning the developement of my film to match the papers I was using. That seemed to give me the best prints with a traditional approach. I have gone back and printed alot of that film with scans and injet prints. I find that I can hold much more shadow detail if I work carefully from a good scan than I could with a traditional print from the same negative by scanning a bit flat and don't clip it. B&w film that I am shooting to scan now I am exposing more and dev less than I would have before. The films I am shooting now would take about a grade 3.5 or 4 to print properly on silver. That is why colors negs are so useful. What I do know is that I can hold a greater dynamic range by two stops at least by my current method.

[Ellen Stoune Duralia]

Exactness of ideas... ??? Gee wiz, I just wish somebody would answer my question (see above) :)

[Michael Mutmansky]

Ellen,

You have to look at the histogram and determine what parts of the histogram represent meaningful data, and then make sure that you have that data between the black point and the white point. I don't use silverfast, so I can't tell you how to do that in their software specifically.

It is important that the histogram be considered carefully, because there is often a good deal of information in the histogram that is extraneous or at the least undesirable for collection that needs to be disregarded when the black and white points are selected (for example, areas beyond the image rectangle will show a density that is normally much lower than the image, and that density range should not be included in the black to white point range or it will compress the rest of the image tones).

Ted Harris and I are working on another article for View Camera to detail a scanning procedure that will provide quality B&W scans. It will involve some scanner testing and then a scanning workflow for negative film. We are expecting it to be in the Sept/Oct issue of the magazine.

---Michael Mutmansky

[Ron Marshall]

Hi Ellen,

I use Silverfast with the Epson 4990 to scan FP4+. I scan it using the negative setting at 16 bit.

After the prescan click on the histogram icon and set the two sliders at the endpoints of the histogram, that is usually where it dips down to zero, but you should read about this setting because there are exceptions which would take me too long to explain here. Then set the "gamma" slider, which controls the brightness of the scan. Since I have been setting the endpoints and gamma correctly I have only had to make minor corrections in Photoshop.

Good luck

[Ellen Stoune Duralia]

Ok... well maybe I was making things more complicated than necessary and thinking I was missing something. (I have a tendency to do that.) Anyway, Ron, that's what I've been doing as well.

Thank you for the clarification, Michael and Ron. Oh and Michael, I am really looking forward to reading the upcoming article.

[Kirk Gittings]

Michael,

I look forward to the article. You guys are making a great contribution. I am intereted on any information on scanner profiling with color and b&w negs. Silverfast and Monaco both do either transparencies or reflected art. Will you guys deal with that at all?

[Kirk Gittings]

About clipping when using the 4990 scanner and Silverfast AI 6 Studio.

I just went to scan something and was thinking about my workflow. For myself it doesn't make any sense to do the clipping in the scanner software because the preview is so poor. I reverse engineered a scan that I did last night-my normal way unclipped until I get it into PS. If I had clipped it in Silverfast with the low quality of the preview I would have clipped too much out of the highlights and shadows. By waiting until PS I could look carefully at the small highlights and deep shadows and make appropriate clipping decisions that I could not begin to even see in SF.

[Harley Goldman]

Kirk,

Are you then saying you leave the highlight and shadow sliders all the way to the outside for every scan? Is that what you mean by scanning unclipped? ( I am scanning on a 4870 using Silverfast Ai).

[Kirk Gittings]

Harley,

That is exactly what I mean, but I am very careful about framing so no extraneous stuff like the film holder or film edge in included in the prescan area or considered by the histogram to prevent the skewing of the histogram as Michael talks about above.

[Michael Mutmansky]

Kirk,

Profiling for negatives is complex, and can be a real problem for a few reasons. I don't think there will be room in the article to discuss profiling because it is really an article unto itself.

Profiling is generally an attempt to get a direct correlation between the source and the output in some logical manner (producing a linear response in the image file that relates to the changes in density of the original, for example). This can be done for B&W the same as for chromes (in fact, the profiling for chromes will help produce a good linear response for B&W, so it probably wouldn't need to be done in a special manner), but that doesn't necesarily result in a scan that looks good on the screen.

The article will explain (hopefully, in language that people can understand) why many people have difficulty with B&W negatives, and provide a little help to get over that hump and into quality scans from B&W negatives.

I haven't worked the entire issue of profiling for B&W in my head yet, and so I haven't tested my current hypothesis about profiling B&W. However, I have a feeling that profiling is unnecessary, and the unnecessary manipulation of the image file could result in more trouble with banding and loss of data later on. This applies only to B&W scanning, not to color.

---Michael

[tim atherton]

have any of you tried the NegPos plugin for photoshop, working from a raw file? (that is, an unadjusted scan, not a digital camera RAW file)

A bit of a learnign curve, but I find it excellent for colour and B&W (the maker just put out a new version that I'm not happy with - the orignal seems to work better for me)

extensive info on the site - small one man and his dog setup

http://www.c-f-systems.com/PhotoMathDocs.html

[Henry Ambrose]

There is the possbility of making a 16 bit unadjusted scan and working on it in Photoshop. At this point you are free from relying on the whims of the various scanner software. I know this sounds extreme but you can do this with great success and learning Photoshop well is a better use of your time in my opinion. This is especially the case if you have more than one scanner or when you buy a new machine. You still know Photoshop so ytou don't have to re-think your entire way of working.

I don't think that there is a possibility of a profile for color or B&W negs.

For color negs the orange mask is variable from run to run so you'd be profiling each day or even each set-up. Its still not reliable even then as slight changes in exposure will change the relationship of the color layers to the mask.

For B&W its not needed - there is no color to manage. Curves will take care of anything you need there. If you are using the "Photoshop and 16 bit scan" workflow you can save a curve in PS for your typical films/developer/scene type and apply that to your 16 bit scans. Or some scanning software lets you save curves to apply repeatedly.

Ellen it sounds like you are setting your black and white points correctly. I suggest that you leave a little room on each end to be sure you get all the info you can and as Kirk stated be sure to include in the scan only the image area and no extraneous out of the frame film.

To further answer the original question, keep in mind that you can do a lot of adjustments in Photoshop or in scanning but you still don't want all the info "balled up" in the middle of the histogram. (unless you want an image with pretty much the same tones throughout). So in thinking about how to expose and develop your film for scanning just go back to how you did it for darkroom paper. Have an intention of what you want the print to look like and apply that intention to getting info to your scanner and into your computer. There is lots of room to play in PS but its lots easier if you hit close to the mark in the beginning. At the same time a super high level of precision in manipulating your film exposure and development is not needed.

The advantage of color neg film like NPS is that it will put good usuable info on the film in a way that you can easily get it into your computer - and thats without any changes in development or screwing around.

The advantage for scanning B&W film is that you can use it to make conventional darkroom prints too - not just digital prints. And if its easier for you to process your film at home in simple processes/chemicals then B&W neg may be a better way to work for you.

[Jeffrey Sipress]

Thanks for the valuable input, Henry.