[filmscanners] Re: Oops?

["" <lists@lazygranch.com>]

I've got the Kodak kit to do positives from B&W film, but I haven't got
around to using it. I'd like to try the set on Macophot 820C, which is a
very fine grain extended red film.

Vuescan has a "raw" option. By raw, I mean really raw, i.e .no
correction what so ever. I'd suggest doing a raw scan and then see if
the blown highlights show up.
Vuescan has a control to set the white clipping point. I'm not sure how
vuescan sets it, but so the theory goes you should allow a small
percentage of the pixels to be clipped on the high end. This is because
often some specular highlight ends up setting the high end of the
display, making most of the image too dark. I like to photograph
aircraft, and this option just plain doesn't work well since shiny
subjects can have many specular highlights. I set this option to zero.

Going back to the raw mode, if your highlight are not blown, you could
try something like this.
1) Do a raw scan, saving in grayscale 16 bit. I think the default for
this is a  positive image. If so, then invert it immediately after you
load it into photoshop
2) In photoshop, go to the adjust levels menu
3) Set the gamma to 6 (middle text box), making the image look very white
4) slide the leftmost slider to the right until you start to see black
specs in the display. This is setting the black clip point.
5) Set the gamma to 0.1
6) move the right slider to the left until the white specs are at an
acceptable level. This is setting the white clipping point.
7) move the middle slider until the image is acceptable. For a bell
shaped curve, this is generally at the peak of the distribution.

Acros and Astia (color slide film)  are low acutance films. The images
don't look very sharp, but they are. I didn't like this low acutance at
first, but now I think it is more realistic.

You have discovered (rediscovered) what people call grain enlargement.
When you take a high latitude film and adjust the contrast to look
natural, the grain gets enhanced. This is why I prefer to do slide film.
It may be harder to scan, but you need to adjust the endpoints much
less, so the grain doesn't get magnified.




scott@adrenaline.com wrote:

>Yes,  I actually have purchased a license for Vuescan and
>haven't given it enough attention, still using NikonScan and
>the Coolscan V for most of my work.
>
>I develop my own B&W negs and then scan them (no darkroom).
>I shoot mostly HP5+ and FP4+, with occasional TMZ. I dev almost
>exclusively with HC110 (B) and recently (H). I try to develop for a
>low contrast, thinner negative to please the scanner, and have achieved
>pretty good results with HP5 in dilution (H) at both 320 and 800 ISO.
>
>
>But I have some problems.
>
>(1) I haven't been so lucky with FP4+, where the highlights are blown
>routinely even with extrememly conservative development, as in
>HC110 dilution H at only 8 minutes.  I did some film speed tests
>per Les McLean's book.   Black cardboard, white cardboard, lots
>of cloth, metal, glass stuff on top. Meter with an incident meter and
>then shoot +2, +1, +0, -1, -2 stops for a whole 35mm roll. Cut into
>three strips and develop different ways.
>
>The coolscan barfed on the highlights (white cardboard) every time
>except for the -2 stop exposures. But then the shadow detail was
>unacceptible, as you can imagine.
>
>I want to use slower films to support some larger enlargements. I'm
>about to start experimenting with Delta 100 and Fuji Acros, but these
>seem to have even less forgiving contrast curves than FP4+ from
>what I read.
>
>I've been trying to tweak analog gain, but this is limited, because big
>tweaks increase grain appearance, which negates the whole point of
>using slower film in the first place.
>
>(2)  I often get what look like weird bright reflections off the grain. Not
>in highlight areas. It's like bright specs, visible at 1:1 mag. This
>stuff really
>makes its appearance known during USM.  I wonder if this is due to the
>Coolscan's LCD light source?  don't know.
>
>(3) As I experiment and futz, I wonder exactly what Nikon's "auto-exposure"
>is doing to the raw scan results. I can't find any documentation. In my
>film
>speed scans, I can see that AE is trying to control the highlights, but
>I don't
>know how AE is doing this. Is it *only* the equivalent of a curve adjustment
>that I could make myself, or is it adjusting the analog gain or maybe doing
>something else?   Any input here would be greatly appreciated.
>
>Anyway, howdy to the list from a new member.  I do need to experiment with
>scanning B&W film as a positive and see what I get going that route.
>
>Scott
>
>
>lists@lazygranch.com wrote:
>
>
>
>>Give Ed Hamrick's Vuescan a try. The demo mode (last time I checked
>>which I will admit was 4 years ago) just puts a watermark on the
>>image.There used to only be one version, but now there is a pro and
>>regular (maybe called basic) version. If you like it, get the Pro
>>version since it is updated frequently. Ed has many profiles for Kodak
>>B&W film.
>>
>>I would think that Nikon's lack of a color mask would make for
>>exceptional B&W scans. On more conventional scanners, people have tried
>>to scan in color and then pick the best looking channel to convert to
>>grayscale.
>>
>>It's really a shame they can't make an  B&W transparency film (other
>>than Scala, which is really "fringe":). I find scanning positives to me
>>much easier than negatives. Yes, the scanner has an easier time with
>>negatives since the densities are not as extreme, but the inversion
>>process is the gremlin.
>>
>>Any particular type of B&W film you find most difficult?
>>
>>Here is an idea. See if the Nikon software will let you scan the B&W
>>film as color slide film. Then see if the histogram is reasonably centered.
>>
>>scott@adrenaline.com wrote:
>>
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>>
>>>I only get messages very, very sporadically. Is there traffic on
>>>this list that I'm missing?
>>>
>>>I'm desparate for tips on getting better scans of  B&W film on
>>>a Nikon Coolscan V, understanding Nikon's "autoexposure" vs.
>>>what I might do myself and so forth.
>>>
>>>Scott
>>>
>>>
>>>lists@lazygranch.com wrote:
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>>>>I have a different problem. My last two posts never showed up.
>>>>
>>>>Berry Ives wrote:
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>>>>>When I checked my in box this morning, all of my filmscanner mail for the
>>>>>last 3 months was gone.  Perhaps I did something...maybe just losing it, my
>>>>>mind, that is.  Anyway, just in case someone expected a response from me to
>>>>>something I haven't seen...
>>>>>
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