The OP stated he has no intention of printing chemically. He's going to make all adjustments digitally in post processing. What recommendations would you give under that scenario?Forget the curves and the mumbo-jumbo. If the high lights are the most important part of the scene then meter to just get detail in the highlights (usually 2 stops more than the "average"). Ditto, if you want details in the shadows, then meter for the shadows. Basis for the Zone system. As an example if you want detail in snow then you need to me meter the snow to have just enough detail to show up in the print. If your photographing a black cat you want enough shadow detail to see the cat's black hairs. Doesn't matter if your making a paper print or scanning. If the detail isn't in the final negative no amount of post processing manipulation will bring out that detail.
A properly exposed and developed B&W negative prints or scans well. Scanning or printing a negative that is 2 stops over exposed or under exposed and normally developed in difficult as is a correctly exposed but under developed or over developed negative. Fine tuning for scanning or printing is the same as each film/developer respond differently. Exposure changes in 1/3 stop and or development changes in 5% increments are the standard fine tune increments.The OP stated he has no intention of printing chemically. He's going to make all adjustments digitally in post processing. What recommendations would you give under that scenario?
If you look at the specifications of the Nikon Coolscan scanners you'll realise that their Dmax values are based on the bit depth. The Cooscan IV/40/2000 are listed as 12bit with 3.6Dmax, Coolscan 4000/8000 as 14bit with 4.2Dmax and Coolscan 5000/9000 as 16bit with 4.8Dmax, clearly this is just stops converted to Dlog (x0.3).I've never heard of bit depth as referring to or indicating dynamic range, only in indicating level of tonal discretion over a range..
This would make sense as the scanner should be optimized for scanning negatives that also print well, and this seems to be supported by my findings.A properly exposed and developed B&W negative prints or scans well..
My reasoning was not correct, there are about 30000 levels in the top 8 stop range of my scanner.The scanner has a Dmax of 4.2 (marketing claim) and an ADC bit depth of 14 bits.
Is my reasoning correct that this means that an image with a density range of 1.8 only has about 6 bits of tonality range for mapping these 10 stops of exposure?
All B&W photo papers unexposed and developed is paper white. As you expose the paper to light then develop it the paper becomes darker. The amount of light at a given aperture where the paper gets no darker is paper black. Wen you print at paper black the enlarger is set to the selected aperture and exposure time to give paper black with the negative either in the carrier or in contact with the paper. Once developed and dry the print is examined for tonality and areas either burned in by giving them more exposure or dodged (blocked from receiving light) to get the desired tone.I am not (yet) familiar with darkroom printing but I believe this is also a good range for printing?
If scanning flat with my Epson, I'll get a range much less than 0-255 unless I set my black and white points just at the ends of the histogram before the scan. Some people have claimed that setting the points before the scan gives you more data than scanning 0-255 flat and doing the levels (black and white points) in post processing. Somehow the way the histogram and data gather, there's more data if you set the points before the scan.All B&W photo papers unexposed and developed is paper white. As you expose the paper to light then develop it the paper becomes darker. The amount of light at a given aperture where the paper gets no darker is paper black. Wen you print at paper black the enlarger is set to the selected aperture and exposure time to give paper black with the negative either in the carrier or in contact with the paper. Once developed and dry the print is examined for tonality and areas either burned in by giving them more exposure or dodged (blocked from receiving light) to get the desired tone.
A negative that has deep shadows with no detail and bright whites in sun light should give a raw scan with the deep shadows between 0 and 10 with the whites between 225 and 255 on a histogram.
Over exposed have blacks that are above the base line of a histogram at 0, over developed have highlights above the base line at 255 on a histogram baring direct sun or bright reflections off chrome.
Can you clarify if it matters to set the points before the scan? Or just set Epsonscan with no adjustments? It scans flat giving the full range, but then you get a very low contrast darker picture that you expand with levels afterwards.No, I was just describing where the end points should lie. If you set the B&W points on the histogram input in EpsonScan be sure to set the output B&W points to 0 and 255 to see the difference. If the input is narrower than the output then it will be expanded on output which may allow additional adjustment range in given tones. If the detail is not in the negative it will not be in the scan or print.
If scanning flat with my Epson, I'll get a range much less than 0-255 unless I set my black and white points just at the ends of the histogram before the scan. Some people have claimed that setting the points before the scan gives you more data than scanning 0-255 flat and doing the levels (black and white points) in post processing. Somehow the way the histogram and data gather, there's more data if you set the points before the scan.
I haven't notice any practical difference having tried both methods. Can you add any ideas on this matter?
No, I was just describing where the end points should lie. If you set the B&W points on the histogram input in EpsonScan be sure to set the output B&W points to 0 and 255 to see the difference. If the input is narrower than the output then it will be expanded on output which may allow additional adjustment range in given tones. If the detail is not in the negative it will not be in the scan or print.
If you look at the specifications of the Nikon Coolscan scanners you'll realise that their Dmax values are based on the bit depth. The Cooscan IV/40/2000 are listed as 12bit with 3.6Dmax, Coolscan 4000/8000 as 14bit with 4.2Dmax and Coolscan 5000/9000 as 16bit with 4.8Dmax, clearly this is just stops converted to Dlog (x0.3).
I did a quick test to measure the actual density range that can by scanned by the Coolscan 4000 by scanning a Stouffer 21 step wedge (density 0-3.0). I scanned to a 16-bit raw Tiff file an measured the values with an averaging color picker in PS and obtained the following chart:
View attachment 253537
As you can see the values are fairly linear up to about 8 stops.
I would say the result are usable up to about 9.5 stops or a density of about 2.85.
Now this is the density range it can handle, not the absolute maximum density as the CCD exposure time will be set by the software for the highest density areas.
For most BW negatives and C41 color negatives this range is sufficient. For color slides this might be an issue as Fuji Velvia 50 for instance can reach a density range of over 3.5. Wide range slide film will definitely gain some shadow detail by doing a multi-exposure scan.
Applying the "expose to the right" principle of digital photography, which I assume applies equally here, I would say that (for this scanner) BW negatives should be developed to a density range of about 2.4 (8 stops), to make optimal use of the scanner range.
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@Koen Van Crombrugghe Wow,just the other day I was thinking that I should do some sort of calibration on my Coolscan 5000. So I have some questions about how you accomplished your scan.
Phil Burton
- Which model (or size) Stouffer wedge did you use?
- If you could do this scan all over would you get a different size wedge?
- How did you feed the wedge into the scanner so that all the 21 steps got scanned?
- Which scanning software did you use?
Would it make sense to develop my negatives longer, increasing the contrast and expanding the range up to a Dmax of about 3.2 to make better use of the scanner's dynamic range?
I beg to differ.Yes. The advice "if it prints well, it scans well" is common on photrio but it's absurd. The paper offers abysmal dynamic range and skillful printing means skillful compression of film DR into paper's limits. Scanning is the complete opposite: you're going from the limited DR of film to a "wider" medium with assumed post-processing, so the skill of scanning is a skill of expanding, so you want as much density as possible without contrast getting out of hand.
Film, like paper, has its limits. A scene can have far more dynamic range than a film can handle but careful manipulation can bring compress that range to fit that of the film. (ever heard or pushing or pulling?)Yes. The advice "if it prints well, it scans well" is common on photrio but it's absurd.
I tend to agree but you need to have a good knowledge of your scanner's capabilities , as testing shows that the official specifications are not a good reference.Yes. The advice "if it prints well, it scans well" is common on photrio but it's absurd. The paper offers abysmal dynamic range and skillful printing means skillful compression of film DR into paper's limits. Scanning is the complete opposite: you're going from the limited DR of film to a "wider" medium with assumed post-processing, so the skill of scanning is a skill of expanding, so you want as much density as possible without contrast getting out of hand.
Let's see how you'll doI beg to differ.
MattKing said:If the negative prints well optically, it means that the dynamic range of the scene is accurately recorded on the negative, with a full range of tones and excellent micro and macro contrast. There is no loss of detail or contrast in the parts of the shadows that matter, nor is there any compression or blocking up in the parts of the highlights that matter. The translation of that information into the more limited dynamic range of a print is handled (relatively) automatically by the photographic paper - the two sets of characteristic curves match up nicely.
MattKing said:The film is designed to faithfully capture the wide dynamic range in most scenes. It may not be a linear capture, but the paper takes care of that for you.
MattKing said:Once the information is in the negative, if the exposure and development are such that it will print well optically, than that information is easily extracted with a scan too.
I tend to agree but you need to have a good knowledge of your scanner's capabilities , as testing shows that the official specifications are not a good reference.
Furthermore you'll need very tight process control to match the dynamic ranges.
Film, like paper, has its limits. A scene can have far more dynamic range than a film can handle but careful manipulation can bring compress that range to fit that of the film. (ever heard or pushing or pulling?)
All film base has optical density. The chemistry used to process the film increases this density with no exposure to the film. This is called Film Base + fog.
Any scanner regardless of software used and any editing software has a histogram. The base line of the histogram is film base plus fog labeled fb+f. A histogram is a graphical representation of the information contained in the scanned material.
View attachment 253613
0 on the histogram is pure black and at base line is no detail or in wet printing is paper black; 255 is pure white and at base line is no detail or in wet printing paper white. The dynamic range of the film or paper in use is irrelevant to these two points. Information contained on the scanned medium is registered above the base line. A perfectly exposed and developed negative with scene detail that fills the range of the film will have the blacks starting at 0 with the whites ending at 255.
View attachment 253614
A over exposed but correctly developed negative will have information above the base line at 0 which cannot be retrieved in either scanning or wet printing.
View attachment 253615
A over exposed over developed negative will have information above the base line at both 0 and 255 which is detail lost and not retrievable by any means.
View attachment 253616
Another way to state this is the exposure is set so that the deepest blacks are just above the start of the toe of the film and the development is such that the highlights end just before the shoulder of the film. Exposure that extends the scene dynamic range into the toe of the film is lost detail from the scene and development that puts the highlights into the shoulder of the film is also lost information. I have yet to see a negative whose detail put the peak of the information between the toe, histogram 0, and the shoulder, histogram 255, beyond the height of the histogram but one may exist and that peak of information will likely not be loss of detail.
Repeating, any negative whose deepest blacks are just above the toe of the film and whose highlights are just before the shoulder of the film will wet print well (not perfect) at paper black and will scan well on any scanner or scanning software.
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