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Thread: Ideal film/developer-drum scanning B&W Landscapes

  1. #21
    Kirk Gittings's Avatar
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    Ideal film/developer-drum scanning B&W Landscapes

    This explanation by Michael is so very very important that I would like it written up and added to the archive. I know you are busy Michael but it would be of great use to me in the future with students etc.
    Thanks,
    Kirk

    "When did photography become a desk job?" Kirk Gittings 2009

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  2. #22
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    Ideal film/developer-drum scanning B&W Landscapes

    "Developing to a low contrast will ultimately INCREASE the apparent grain and noise effects in the image by extrapolating the data outward in the digital realm, which may cause the subtle noise artifacts to become more prominant."



    "... adjustment of the midtones causes a seperation in the steps somewhere in the curve, and a compression of the steps in another part of the curve".



    Wonderful explanation !

    I'm glad the original question was asked, even if it was for the nth time - I learned something most valuable. Thanks !

  3. #23
    Scott Schroeder's Avatar
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    Ideal film/developer-drum scanning B&W Landscapes

    I agree, excellent information! Now I need to go reread Michael's VC article. I think it will make more sense this time.

  4. #24
    Kirk Gittings's Avatar
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    Ideal film/developer-drum scanning B&W Landscapes

    Brian,

    I am simply but confusingly stating that if I want a final print with rich mid tone contrast (like the old Tri-X HC110 look that I like so much), I do not want to do a flat low contrast "raw" scan which I have to apply a steep curve to later on. I want to scan it (sample it) at a tonal separation (mid tone contrast, end points etc.) close to the final tones that I want in the print.
    Thanks,
    Kirk

    "When did photography become a desk job?" Kirk Gittings 2009

    KIRK GITTINGS
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  5. #25
    Abuser of God's Sunlight
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    Ideal film/developer-drum scanning B&W Landscapes

    I'll seccond the recommendation for tmax. Grain in the 100 speed is smaller than can be resolved at 2400 ppi, and the modulation characterics of the film are so outstanding that you can presum zero loss of quality in the film stage in enlargements smaller than 4x.

    I'd recommend against developing for adjacency effects. Doing so is like sharpening the image on the negative. The problem is that the effectiveness of any sharpening operation is completely dependent on enlargement size. Photoshop gives you much more flexibility to get it right for the particular size you print, and to do so with less loss of information.

    Personally, I would not worry about the amount of information being lost to a single, moderate application of a curves layer (which is all the tonal adjustment a decent negative should require). Regardless of whether you're getting 16 or 15 bits, you're getting a lot of them. In my own tests I have had to commit acts of uncommon brutality on a 16 bit scan before problems started showing up in the histogram. Even more to get problems to show up in a final print. At any rate, I haven't compared the virtues of low vs. high contrast negs for scanning. My tmax negs are on the low contrast side ... they print on grade 3 paper. And they scan great. But I do not think you'd have problems seeing into dense highlights on negatives that are a couple of grades more contrasty, even with a consumer scanner. Even a fairly dense bw neg is a lot less dense than a typical chrome.

    If you accept that tweaking the tones with a curve layer won't kill you, then your film/developer combination is absolved from having to provide the perfect tonal scale. You can chose your developer for more workmanly qualities: speed, grain, resolution, how nice it smells, etc.. Acknowledging Kirk's point, it makes no sense to take this to extremes. And it makes all the sense in the world to get your scanner software set up to deliver a raw scan that's in the ballpark.

  6. #26
    Kirk Gittings's Avatar
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    Ideal film/developer-drum scanning B&W Landscapes

    "Even more, most B&W files don't have anywhere near the theoretical number of possible levels of gray in them, most have much fewer than 1/2 and high bit files (16 bit) may often have 1/3 or 1/4."

    Michael,

    Does this suggest that one should perform most of the workflow on scanned b&w neagatives in RGB?
    Thanks,
    Kirk

    "When did photography become a desk job?" Kirk Gittings 2009

    KIRK GITTINGS
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  7. #27

    Ideal film/developer-drum scanning B&W Landscapes

    Brian,

    You know, when I wrote that, I knew it didn't sound right, but I missed what my error was.

    Yes, I mean it needs to be done as an adjustment LAYER, not Level as I wrote in the above.

    -------

    The discontunity I mention is the region on the negative where there is a substantial density change due to a luminance change in the subject. The problem is, there are not only ideal (abrupt, instantaneous) contrast changes (like a tree silhouetted against a sky), but situations where the transition is rapid, but covers some visible range of the negative.

    These rapid contrast change regions often have very distinct steps to them, and they can be visible because they are more than a single pixel wide, as an instantaneous change may occur. Now, add to that some digital noise from the scanner, and when a substantial Curves adjustment is made, problems with banding, digital hash, and other scanning artifacts can show up.

    -------

    As far as I know, the specifications of the flatbed scanners can be trusted (to a certain extent). Some of the older pro scanners have 14 bit CCD technology, so they are probably only able to output 14 bits of data to the file, even though it is a 16 bit file. What is essentially done is the remainder of the file is filled with "0's".

    All of the modern consumer scanners are 16 bit, but again, that doesn't mean you are getting 16 bits of data in the file. That is the theoretical limit of the data that the CCD sensors can provide, and it doesn't mean that they will actually deliver that amount.

    Besides, most images are not evenly distributed with tones in a manner that will give you data in all 16 bits anyway, so all of these things are essentially theoretical in the first place.

    Don't worry too much about the bit depth issue, I was simply making a point that most drum scanners are not capable of the bit depth of the flatbeds, but they are still capable of very high quality results when operated by a knowledgeable pilot. The same goes for many of the scanners out there, within their reasonable limits (and you need to know what these limits are for your particular scanner).

    ---Michael
    Platinum/palladium, gum bichromate
    and photogravure printing

  8. #28

    Ideal film/developer-drum scanning B&W Landscapes

    Jack,

    Now, I'm pumping 999 resolution to the 4800 when I print and getting fairly good looking results

    I suggest you do a few tests on this. My experience is that it is better to do the interpolation in the computer rather than in the printer. The older Epson printers operated at 360/720/1440 ppi in native mode. That means that if you send them a file that is not at one of these resolutions, the printer has to do an interpolation, either in the hardware, or in the driver.

    I was originally under the impression that the Epsons were native at 360ppi, but I have seen some evidence that they may actually be native at a higher rasolution, possibly 720ppi, but I doubt it would go as high as 1440ppi.

    I suggest you do some clip tests from a high resolution file set to print at the same size, and send the printer a raw (999ppi) file, and then send the same one downrezzed to 720, and then another downrezzed to 360ppi. Then compare.

    You will have to sharpen each file independantly, and you should start with an unsharpened source for the downrezzing so you don't cause sharpening artifacts. Also, when you do the final sharpening, you have to remember that the amount you do needs to be based on the output resolution, and what is best for printing at a particular size will probably look to be too much on the monitor, especially if you are printing at a very high resolution like 720ppi or more.

    My guess is that the 720 downrezzed file will print the best on the printer, followed maybe by the 360ppi, and then then 999ppi file. The differences will show up in edges and lines mostly, but there will probably be a visible difference.



    ---Michael
    Platinum/palladium, gum bichromate
    and photogravure printing

  9. #29

    Ideal film/developer-drum scanning B&W Landscapes

    Kirk,

    Does this suggest that one should perform most of the workflow on scanned b&w neagatives in RGB?

    Yes and No.

    I considered this possibility a while back, because using RGB is essentially like multisampling in one step. It takes three different CCD scans of a particular point on the film and then in PS you could combine them by converting to grayscale, and you will suddenly achieve over one more bit's worth of data in the file. This could be beneficial in a negative that is prone to noise in the scan, or an image that happens to have the kinds of details that noise shows up in.

    However, with the typical flatbed scanner, there is enough of a lack of perfest registration that using all three channels will soften the image, sometimes considerably. The same goes for drum scans, but the registration is probably better enough that it may be worth considering under some circumstances.

    It is possible to actually have this increase the noise level as well, depending on the scanner capabilities. On many scanners, the Red channel is the most prone to noise. If you did an RGB scan where the G and B channels were pretty good, but the R channel had a good bit of noise, you would be better off not using the R channel in the composite scan.

    I have tried a bunch of these variables. I think that the results are going to vary for each scanner type, and may also vary based on the conditions of the electricity in the house, etc. but if you care about reducing the noise, multisampling and combining the G and B channels in the Channel Mixer will probably produce the best result.

    It won't necessarily produce the sharpest result, however. If you have the ability to do multiple sampling in a single scanner run, then the best will probaly be to scan that way, and then use only a single channel from the output.

    Let me think about the multichanel benefits for the Curves manipulations a bit. There may be a benefit for times when banding or noise shows up. I may have an approach that would help alleviate that.

    ---Michael
    Platinum/palladium, gum bichromate
    and photogravure printing

  10. #30
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    Ideal film/developer-drum scanning B&W Landscapes

    This is interesting. In my testing, I've found just the opposite of what Mr. Mutmanski has found. In particular, I've found that I get better results, including less graininess in the print, by decreasing developer time and thus negative density. In Zone System land, my normal development is N-1 to maybe N-1.25 which seems to be about optimum for me.

    This is doubly perplexing, since Mr. Mutmanski and I are both using nearly identical drum scanners - he's using an Optronics ColorGetter Falcon and I'm using a ColorGetter 3 Pro IIRC. Both using the same ColorRight Pro 2.0 software to drive the scanner IIRC.

    Here are the steps I took to come to this conclusion. First, I went to the literature. Haist and Henry and a handful of other researchers. I learned what I could about what determines graininess and acutance. What I found was that grain clump size (dye clouds if you want to think in terms of color films) is controlled by a handful of factors, some of which are interrelated.

    The biggie is the film's ISO rating. Fast films have bigger grain than slower films. Next on the list seems to be developer type (solvent vs. acutance). It's a trade off. To get smaller grain size, you give up some acutance. To get higher acutance, you get larger grain. Next is density. More density means larger grain size. Most of us know this instinctively as we seldom have grain problems anywhere but the highlights. This is one of the big reasons for the continuing popularity of transparency films, particularly with the 35mm crowd -- in transparency land, the dense part of the film is the shadows where it is hardest to see grain problems, while the highlights show the smallest grain. After that, you end up with the interlocking parameters of processing temperature and processing time. Notice that agitation doesn't directly effect graininess - only through the effect it has on processing time. That is, if you want smaller grain and agitation is your only tool, then use constant agitation (counterintuitive, that, but it has scientific backing).

    Armed with this knowledge, I ended up with the following. First, Tri-X. Reason: I need the speed. Second, Jobo CPP-2 and 3010 tank. Reason: I want consistency beyond what I can get with other methods. Third, XTOL. Reason: It straddles the line between solvent and acutance developers, exhibiting less solvent behavior as you dilute it, and it dilutes very well. That, and I found I had problems controlling HC110 with constant agitation.

    Given this, I proceeded to find my EI and normal development time per the Zone System. I started out with XTOL 1:3, 20C, 10 minutes, about 30rpm. From there, I started reducing time and therefore reducing DMax and therefore contrast. At each stage, I would scan at 11x (10x with some room for cropping if I need it) with an output of 360 dpi, or nearly 4000 ppi scanner resolution (The scanner software wants the degree of enlargement at your output size and resolution; it doesn't expose to the operator the resulting scanner resolution). This results in a file about 550MB, 16 bit grayscale. I would take a 30 cm square chunk out of the full size image and print it on my Epson 7600 using selenium PiezoTones. This in turn went up on my proofing wall. I posted them side by side under the same lights.

    I found small but steady improvements in the print going down to about 6.5 minutes. The scanner's densitometer told me that I was getting zone VIII values in the 1.0 range at 6.5 minutes, down from about 1.35 at 10 minutes. That's a bit more than N-1 in my book.

    What I found in my prints (sections out of what would have been 125 x 100 cm (about 50 x 40 in) prints I could print the whole thing) was this. As developer time went down, graininess went also went down. That is, it went from being barely visible to being invisible. I want to emphasize here that it's not a big change, but it's noticeable if you are looking for it. Acutance improved very, very slightly.

    Some of these images I've now had printed on canvas at 125 x 100 cm. The full size prints verify what I saw on the 30 cm sq. sections. At this level (about 10x enlargement), I can see no grain, even when I take my glasses off and put my nose almost on the print (about 22 cm (8.7 in). Likewise, acutance is excellent. Likewise, tonality is excellent.

    So, that's what I've found works for me. Tri-X, XTOL 1:3, 6.5 minutes at 20C, Jobo CPP-2, 3010 drum, resulting in N-1 or a bit less development.

    When I scan, I take good care in setting my white and black points and my output contrast curve. In Photoshop, I touch up the white and black points with a levels correction. I often find that I don't need a curve correction at all. I do much less dodging and burning (local contrast corrections) than I did making darkroom prints, and I get better shadow detail and highlight detail than I could in the darkroom. Make of this what you will.

    Bruce Watson

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