f64

[Ken Lee]

The actual resolution of Kodak Tmax-100 can be found in the Kodak document F-4016. It is 63 lines/mm at TOC 1.6:1 and 200 lines/mm at TOC 1000:1.

See http://www.kodak.com/global/en/profe...16/f4016.jhtml

Sandy King

What does TOC stand for please ?

[onnect17]

What degree of magnification are we seeing here ?

Ken, Should be around 1mm between digits in a 35mm TMX, scanned in a Nikon V ED at 4000dpi. The better one is Pyrocat-HD. The other one is xtol.

TOC (Target Object Contrast)
I found it here --> http://www.agfa.com/sp/en/binaries/A...m221-42588.pdf

[Lenny Eiger]

Perhaps posting the 2666 spi scan might help clear things up a bit-
maybe there is more information in the original scan that is being lost to compression? or some other reason?

I am sure that would be better. If there was enough bandwith, I might. 3 Gigs is pretty large. When I look all the way into the grain, it is quite sharp. In fact, when one looks at the different micron apertures, there are some choices. The sharpest one usually does not print the best. It is the next one down, the one that smoothes the grain a bit, but still maintains the details in the image. When one looks at a lightning bolt on a droplet in that tiny a sample, that is holding said details that may or may not appear in the print at a large enough size. Using a sharper aperture will have more grain and anti-aliasing effects. The visual inspection that many are doing is an incorrect analysis. This is not about comparing bars. My test was not about the bars, it was not about resolution at all. I think talking about resolution is pretty meaningless. The only thing that matters is what you can do with the final print.

- well, that, at least to me, is debatable- unless you refuse to accept debate. Not that it matters to me much, I'll draw my own conclusions no matter how things are spun, based on the evidence presented-

I don't refuse, I'm just not that interested. You see, I have this piece of film here that I am looking at and all I care about is what I see as the result of my test. I don't need anyone else to help me analyze things, or figure out what happened, or whatever. I am very clear what the capabilities of my printer are, and I don't think it will differentiate the difference between different fstops, or if it will, it won't be dramatic enough for me to care.

As far as your own conclusions are concerned, I would hope you would draw your own. I have drawn mine.

However, since maximizing depth of field is the stated aim of a few here, it leaves me wondering why smaller formats aren't used- perhaps greater depth of field would be slightly easier to achieve that way-

That's not my aim. My aim in this test was to test the ability of different formats to render textural details in a print, in my system. The f64 was a small surprise that I found gratifying.

You say - "The calculated numbers in a previous post about 72mp being the max for an 8x10 are patently ridiculous." well, I don't find it ridiculous, but I'm open to being convinced otherwise-
if your 2666spi sample contains a lot more resolution than is shown in the reduction, then I'll be happy to accept it-

But as it is, I can only accept what I can see for myself-

Exactly. So take a picture, go get a scan from someone with a great drum scanner, who knows what they are doing, have them scan it while you are standing right there, helping set the parameters for how you would like to see it in the final print and you will have your answer. If you can't tell the difference at that time from a digital shot at 22 megapixels, or whatever, then you'll have your answer.

If a microscopic scanning of the film grain is the purpose of the exercise, then I'm sure it has been a successful one- however, if the purpose is to disprove the existence of diffraction effects, well, on the evidence, I remain unconvinced-

The numbers in your last post have little meaning to me, you might have chosen 3000, or 4000 instead...

I think you are adding to the trash talk. The reason I use those numbers is that what the scanner is actually scanning at. I have no interest in disproving anyone's ideas about diffraction or its existence, all I said was that I was surprised to find a lot more quality at f64 than what I was expecting given the word on the street about this.

If you want to prove diffraction is awful go do your own tests. You can consider my information totally anecdotal, that one person had a single result. Despite what it may seem, I'm really not here to argue about it.

Lenny

[jb7]

I think you are adding to the trash talk.

Thank you.

[Bob McCarthy]

FWIW,

10 inches x 2666 pixels is 26,660
8 inches x 2666 pixels is 21,238

The product of the two is 568,604,480 , or 568 megapixels...

That's only the number of pixels, and not the resolution... of course. Also, of course, I don't believe the resolution is less than 1/5. But that's just me.

Lenny

I agree with you Lenny, where does the 900 spi come from. Is he confusing resolution which is made in lpmm (30x30) with scan sample frequency.

There may not be 500 megapixels of information there, as that is scene/film dependent too. but there is the potential.

Bob

[Ken Lee]

Ken, Should be around 1mm between digits in a 35mm TMX, scanned in a Nikon V ED at 4000dpi. The better one is Pyrocat-HD. The other one is xtol.

Thanks for that. At 360dpi, we could enlarge that 4000spi sample by around 11X. That would be a roughly 10x17 inch print from 35mm. I can certainly see why we would want to use something like Pyrocat HD for roll-film ! The difference is way more than just graininess.

I see that your Photoshop screen capture, shows the images at 200% magnification. Perhaps I am mistaken, but doesn't that mean we are seeing scanner pixels at that point ?

(Whenever I look past 100%, that's what I see. The higher the % over 100, the more we see pixels, until eventually, the image looks like "tiles").

In the photos below, the sky appears to have grain in the second image - even though it's the same as the first image, just scaled to 200%.

100% - Looks smooth


200% - Exact same image - but looks ragged - sky appears "grainy"

[Brian K]

What does TOC stand for please ?

I'm not sure what the acronym TOC stands for but it relates to normal scene contrast. So you use the 1.6:1 figure for a truer sense of the films resolution. So the resolution of T-max 100 is 63 lp/mm, I believe in one of my previous posts in this thread I stated a range of 60-65 LP/mm.

As a side note, the late great TechPan had a resolution of 200 lp/mm at 1.6:1

[onnect17]

Ken,
The purpose of the side by side comparison was to show a loss of sharpness between developers, which probably could go unnoticed until you have to deal with the enlargement/printing and/or you scan with half the optical resolution (2000dpi). I think the idea is clear in the image.

You’re right, the original cropped fragment contained around twice the size (200%) and unfortunately the image gets altered with all the cut/paste and during the posting (I think it get resized to 650 x ?). If I have the numbers right what you see is “magnified” 1.5 times.
Still what appears like noise is not. 4000 dpi gets close to the size of the grain in this emulsion and due to the light source in the scanner the visible grain is sort of mixed with the scattered light. Good or bad, I doubt you could get much detail of the grain in tmx with an Epson scanner.
Too much dispersion/diffraction in the path, plus CCD.

I think the advantages of the stain in the negative for scanning are still undervalued. But that subject is good enough to start another thread.

What I can notice in you images is the product of compression artifacts (perhaps jpeg) after some sharpening and the resizing interpolation. With a clean scan I feel confident enough to resize 20x without any sharpening and/or grain filtering.
Grain is my friend, even if I want him smaller.

You're more than welcome to take my V ED for a week in a trip to western mass.

[Ken Lee]

Thanks for explaining that. I'm sold

Thanks for the offer. I don't have any 35mm to scan at this time. I had one of those scanners. They are terrific. I wish I hadn't sold it.

[Kirk Gittings]

Lenny, here's a small sample of developers affecting sharpness in negatives.

What is the chemical mechanism where one gets more pronounced grain (and what appears to be sharper grain in the Xtol example) AND less sharpness in the DETAILS of the letter image? This seems counter intuitive me.