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I tried it when it first came out, but I had processing problems of an unusual nature. I got these little marks that looked similar to static electricity, but not exactly. Kodak and I checked it all out and finally decided that I was heavy handed. Apparently TMAX is mechanically sensitive and whatever it was that I did, I mechanically exposed the film, either in the tray development or the sheet film holders.
Oh well.
To reply.
Aliasing is just the tonal ends not having information, even 32 or 16bit can be tricky in scanning as scanners being digital they clip. Punchy negs have a nice even contrast range but with definite areas of tonal definition, therefore mentally we make up for the missing areas our vision. Other end of the scale tonal gradients Mach Band. Flat negs give far too much work in photoshop / (place post production tool here).
In the same way CD's are mastered off of heavily compressed 48khz audio for punch. Imagery is the same. Providing it isn't clipping there is a much better chance of getting a fast turnaround and more rewarding image. If the neg is exposed well a punchy neg will scan better than a flat one.
I must disagree. I thought this too once, but extensive experiments proved me wrong.Quote:
Originally Posted by scrichton
For context, I'm drum scanning 5x4 Tri-X. What I found was that the scanner makes a better scan from a negative that is somewhat thinner than a negative optimized for darkroom printing. Say a Zone VIII of about 1.0, or in Zone System terms, an N-1 negative.
I speculate (I'd have to do actual science to form a theory ;-) that the prime reason for this is the Callier Effect. As negative density increases, so does light scatter from the metallic silver. In the scan, this results in differential local contrast across the negative's density, with highlight areas (high density) getting lower local contrast than shadow areas (low density). This is very similar to what happens with a darkroom enlarger. For both systems, optimization is toward thinner negatives. These thinner negatives have considerably less differential local contrast, and the resulting scans require less correction in Photoshop in my experience.
I've done a little work with a consumer flat bed and found similar results.
All this said, there's really no reason for anyone to believe either of us. It's too easy to do the experiements for one's self and find out what works best for one's own workflow.
I've had very good results with 8x10 Tmax 400, and I'm pretty cavalier about processing film. The reciprocity characteristics make it my favorite film for nocturnal shooting.
Sounds right to me. And it's probably dependent on the nature of the light source, how collimated is the beam... if there is a beam at all.Quote:
Originally Posted by Bruce Watson
I would guess that most flatbeds use a diffused light source, while "negative scanners" for small and medium format probably use a "straighter" source.
What do drum scanners use - or do they vary from model to model ?
On a related note, would film developed in staining formulas be more, or less susceptible to this influence ?
To follow up Bruce's experience with a recent one of my own:Quote:
Originally Posted by Bruce Watson
I recently dosed a batch of Tmax400 negatives with developer (Pyrocat HD) that was on it's way out, so they ended up a thin (about 1/2 to one stop thinner than normal) and flat - at least .2 less in ES. Silly - I new the developer was getting on for a year old. However, despite the thinness and lack of contrast, they scanned extremely well on a consumer flatbed - basically, if you just have a sliver of silver in the shadows, it still translates into good shadow detail. In my experience, the same negatives would just print with completely blocked shadows in the darkroom, but the scans work fine.
It's like condenser vs. diffuser enlargement. Both exhibit Collier Effect, but one a bit more than the other. So one wants a little more density than the other.Quote:
Originally Posted by Ken Lee
Most drum scanners use highly collimated light.Quote:
Originally Posted by Ken Lee
One would think (oh, be careful there!) that a staining developer would give you a negative that is easier to scan. The reason for this is that only part of the negative's density is from metallic silver. The rest if from stain, which is translucent and won't exhibit Callier Effect.Quote:
Originally Posted by Ken Lee
I'm wondering what effect the color of the stain would have, and whether it would be worth it to capture this color in the scan. I can imagine that scan color would change the response of the individual channels (RGB). What I can't image is what this would mean to the final print. Getting these questions answered would take some experimentation for sure.
The only way to be sure is to make some photographs of the same scene, develop these films to different densities, scan the negatives, and see which one gives you the "best" file, however you choose to define it.
I personally find very contrasty negatives difficult to scan!
While my observation is more from experience than analysis, I find that a somwhat compressed tonal range in a negative scans best with lower end scanners like mine. This is probably due in part to the limits of the device. Creating more contrast later is easy, but restoring lost detail or capturing more range than the scanner can do in one scan is a problem. It is the compression of tonal range that 100 TMAX seems to do very well indeed - it puts things within range of the scanner. Most of what looks like grain in an 8x10 scan is scanner noise from what I've seen (sure, probably some aliasing effects too, but not a lot). When the scanner is operating in its optimal range, the apparent grain/noise is less. Films that build up a lot of density yet retain detail in that density are difficult to scan for me, but easier to print contacts from. In DDX at least, 100 TMAX does not seem to build up density very fast, yet film speed seems good enough to give shadow details. Best negs seem to be those that are exposed for shadows and then slightly underdeveloped to normal development for 100. I'm sure that people enlarging the same negative might not like it as much.
I can't afford a drum scanner. Like most. So a punchy neg on a transparency hood is ok. Due to an inherently low DMAX over a true transmitted light scan. Sorry for bringing this up. I have found a punchy well exposed (not blocked) neg will be fine. As I said use lightmeter on incident and average out well enough you will find it very easy to produce a neg that will scan well on a reasonable scanner such as a V700/750 with tranny hood. Low contrast negs compress the black to a point of aliasing or produce bad midtone grey blocks due to mach banding.
I had ortho film last week where the highlights were blocky and lo and behold they didn't scan well. Last week some stuff which had punch but no overexposure. Scanned nicely.
I'll end this debate here. Flatbed + Punchy (not overexposed neg) = easy scan with little post. This is dependent on overall skill in both processing and general computer imaging. I taught for adobe last year and have been processing black and white for 8 years so I have found my perfect combination for my subject matter, as with focus etc expericience will let you know. Look for your own combination.
I'll re-iterate though t-Max 400 will see you right as long as you follow lab results as kodak have made, in their own developer going for an "average density", if you think the subject will be high contrast underexpose by a stop or otherwise for excessivly low contrast. Just remember and fix for at least 10 mins in normal fix. This will clear up all the usual T-Max issues. Then sit back and enjoy a grain free world without loss of speed.
Really? You get grain aliasing in the least dense part of the negative, where there is the least grain?Quote:
Originally Posted by scrichton
I didn't know there were any scanners out there that had such bad electronics that they would produce Mach banding. Human perception does this all the time, but most electronics have sufficiently well damped response to eliminate this. That aside, I would think that increasing local contrast (making it "punchy") would increase the incidence of Mach banding simply because you'll create more opportunity for it since Mach banding is created by the juxtaposition of light and dark regions.
And I'll reiterate that your experience differs from most. That doesn't mean it doesn't work for you. What it means is that most people find the opposite works for them.Quote:
Originally Posted by scrichton
Underexpose? And loose my shadow detail? Not on your life.Quote:
Originally Posted by scrichton
What works for me, and seems to work for most of us, is to expose for the shadows and develop for the highlights. If you do that, I agree that 400Tmax will serve you well.