Medium Format Resolution

Les Sarile · Mar 9, 2018

jim10219 said:
Yes, but I don't have a way to upload files of that size to this site, plus, I don't want to go through all of the hassle. But it's well documented on the internet. You can Google it all for yourself if you like.

Too bad. I just posted this thread -> Real scanning details
In it I compare scanning details achieved by a Coolscan, 14.6MP and 36.3MP DSLR on a frame of 35mm film.

Ted Baker · Mar 10, 2018

jim10219 said:
You can’t resolve the grain with a flatbed scanner. Not even close.

I agree, with any digital device you can't really "resolve" the grain with any real fidelity, but that's doesn't mean you can't detect or see it. For example Kodak use a aperture size of 48µm for the granularity measurements they publish to give a measure of a films granularity or grain, this works out to be about 530dpi, so you don't need a very high resolution to detect the grain.

This combined with sharpening algorithms, and the many re sampling operations necessary will give a different rendition of grain, depending on its treatment. In addition the epson scanners use pixel shift to improve their resolution.

E. von Hoegh · Mar 10, 2018

AlNY said:
Thanks everybody.

Just a few details I left out .I used HC110 dilution B. I scanned at 1600 dpi, 4800dpi and around 6000 dpi. The old scans were from "Dans" I believe.

I don't have access to the images now. At work and will upload later.
I will continue to play with the scanner and will send a roll to the lab. Just surprised at the lack,of resolution with the neg/scanner combo.
Thanks for the advice. Maybe when you see the images the issue may be more defined.

Al

Have you examined the negatives to ascertain if they are indeed sharp?

Ted Baker · Mar 13, 2018

AlNY said:
Attached are the images. They were processed minimally in Apple "Photos". ( I wish Apeture was still around)

I am currently experimenting with different deconvolution algorithms (de-blurring), if you fancy sending me a crop of one the scans done at a minimum of 3200dpi but ideally 6400dpi, I will see how good I can do compared to the Canon, the crop would be ideally include the eye, say 500pix x 500pix in 16bit. I don't have the epson v850 nor any tri-x in 120.I have the model before the 4990 which is very similar but does not have the extra lens yours does.

Send me a PM and will send link, otherwise please ignore.

WilmarcoImaging · Mar 30, 2018

Tri-X is for sure more grainy than TMX. My 6x7 scans of Portra 400 in 120 are 300+ Mb. Scanned around 4000 dpi on an Epson V750 with Epson Scan. 4x5 Portra scans are close to 1 Gb.

Poisson Du Jour · Mar 30, 2018

WilmarcoImaging said:
My 6x7 scans of Portra 400 in 120 are 300+ Mb.

What? Can't be. Not for the Epson V* series and certainly not for my Epson V750.

Ted Baker · Mar 30, 2018

Poisson Du Jour said:
What? Can't be. Not for the Epson V* series and certainly not for my Epson V750.

(4000x2.25inches)^2*2*3 is about 480Mb its even more with the infra-red channel.

Les Sarile · Mar 31, 2018

Poisson Du Jour said:
What? Can't be. Not for the Epson V* series and certainly not for my Epson V750.

It is if you save to a 16bit TIF file.

Alan Edward Klein · Mar 31, 2018

I get 200mb+ files when I scan my 6x7's on a v600 AT 2400BPI and save as a TIFF.

Poisson Du Jour · Mar 31, 2018

I'm not at my studio for the Easter break, so will have to check up unlayered final .tif file sizes much later, but the file sizes here strike me as curious and quite large.

Alan Edward Klein · Mar 31, 2018

Here's a chart showing file sizes of scans.
http://www.filmscanner.info/en/Bildgroessen.html

Les Sarile · Mar 31, 2018

Alan Edward Klein said:
Here's a chart showing file sizes of scans.
http://www.filmscanner.info/en/Bildgroessen.html

Good resource. They list two filesizes for TIFs - first size is 8bit and the double in size is for 16bit version. Of course JPEG file sizes are not standardized as it all depends on the amount of compression. For 35mm @ 4000dpi I can vary from less then 5 to a maximum of 20 megabytes.

Ted Baker · Mar 31, 2018

Les Sarile said:
Good resource. They list two filesizes for TIFs - first size is 8bit and the double in size is for 16bit version. Of course JPEG file sizes are not standardized as it all depends on the amount of compression. For 35mm @ 4000dpi I can vary from less then 5 to a maximum of 20 megabytes.

If you save the tiff with compression you can potentially save quite a bit of space.

Les Sarile · Mar 31, 2018

Ted Baker said:
If you save the tiff with compression you can potentially save quite a bit of space.

Never heard of compressed tif. Is that a lossy format version? Is it proprietary?

Ted Baker · Mar 31, 2018

Les Sarile said:
Never heard of compressed tif. Is that a lossy format version? Is it proprietary?

The tiff standard supports LZW and ZIP, not all programs support it. Both are lossless compression, you can of course use an external program to compress the files.

I am not sure if niconscan supports it, but there is nothing stopping you from using something like imagemick to resave the file with zip compression, you just need to check your editing can read the compressed files.

Alan Edward Klein · Apr 1, 2018

Irfanview 64 bit (free) on my Windows desktop supports both ZIP and LZW compression of TIFF. I just tried it and the ZIp and LZW files are 1/2 the original TIFF in size. How do these "compress" it lossless?

I just checked my Lightroom. It will save TIFF files Zipped but not LZW.

Ted Baker · Apr 1, 2018

Alan Edward Klein said:
How do these "compress" it lossless?

By replacing larger sequencing of bits or patterns of bits with smaller sequence of bits, in combination with a structure so you can translate it both ways. Text compress very well for example because even though 8 bits are used, for each character which allows 256 characters, we typically use a lot less, and vowels get repeated the most.

Alan Edward Klein · Apr 1, 2018

Ted Baker said:
By replacing larger sequencing of bits or patterns of bits with smaller sequence of bits, in combination with a structure so you can translate it both ways. Text compress very well for example because even though 8 bits are used, for each character which allows 256 characters, we typically use a lot less, and vowels get repeated the most.

How do they differ from jpeg compression that does cause artifacts?

Alan Edward Klein · Apr 1, 2018

...and banding?

Ces1um · Apr 1, 2018

Programs like WinZip are based on lossless compression. They remove this redundant information when you compress(or “zip”) the file and restore it when you uncompress (or “unzip”). Nothing is lost. In the image world, PNG files also use lossless compression. -source is https://www.makeuseof.com/tag/how-does-file-compression-work/

Alan Edward Klein · Apr 1, 2018

But how does it do that with photos as opposed to text since each color can be slightly different than others? After all, that's what causes banding in jpeg.

GRHazelton · Apr 1, 2018

The OP was using a V850 scanner. I found that with my V700 scans of 120 film shot with my Pentax 645n on slow film camera on tripod, etc, the image was inferior, probably because of film "unflatness"; if the edges were sharp the center wasn't, and vice versa. No amount of fiddling with the carrier supports fixed the problem. I got a carrier from betterscanning.com and some Anti Newton's Rings glass flats and, with quite a bit of fiddling with the fully adjustable supports on the carrier, got evenly sharp scans. 120 film stock seems much "floppier" than 35mm stockSuch a replacement carrier might fix the OP's problem.

BTW, the OP mentioned that the RB was "the one that fell...." was it perhaps knocked out of alignment?

Ted Baker · Apr 1, 2018

Alan Edward Klein said:
How do they differ from jpeg compression that does cause artifacts?

loss-full compression work on the same principal of replacing larger patterns with smaller patterns, using a structure, to translate one from the other. However freed from the constraint of having to recreate the original, the compression can be more effective. It uses the principle that certain difference are indistinguishable to the eye to be more effective in this replacement, however it is not perfect and sometimes the eye can distinguish the difference, hence the artefacts.

Alan Edward Klein said:
..and banding?

Banding has nothing to with jpeg. It is caused by using too small a bit depth for the task at hand. 8 Bit with gamma encoding is right on the visual threshold that is required for display on a computer monitor. i.e. there is not much additional room for tonal expansion. An 8 bit file saved with a linear encoding will cause banding.

faberryman · Apr 1, 2018

jim10219 said:
And this is a link showing how medium format film has even higher resolution than I stated. Apparently a 6x6 negative has the equivalent of over 80MP.

Theoretically.

Alan Edward Klein · Apr 1, 2018

Ted Baker said:
loss-full compression work on the same principal of replacing larger patterns with smaller patterns, using a structure, to translate one from the other. However freed from the constraint of having to recreate the original, the compression can be more effective. It uses the principle that certain difference are indistinguishable to the eye to be more effective in this replacement, however it is not perfect and sometimes the eye can distinguish the difference, hence the artefacts.

Banding has nothing to with jpeg. It is caused by using too small a bit depth for the task at hand. 8 Bit with gamma encoding is right on the visual threshold that is required for display on a computer monitor. i.e. there is not much additional room for tonal expansion. An 8 bit file saved with a linear encoding will cause banding.

This raises a question in my mind. What compression is actually required for jpegs? You can actually set the percent so high the resultant jpeg is bigger in size than the original tiff. But what is a good compression amount? I tend to set mine very high like 90% because memory is cheap. What are good settings? Should they vary depending on the application?

Medium Format Resolution

Privacy & Transparency

Privacy & Transparency