Size of Film Grain?

Existing Light

Member
Joined
Sep 30, 2009
Messages
457
Location
Huntsville,
Format
Multi Format
I'm not quite sure where to put a thread like this, so I might have it in the wrong forum.... :\



Over the years, people have asked me why I shoot film. I give all the usual answers like "I like working with film and working in the darkroom" and "I think analog prints look better than digital prints, assuming the analog prints are done well."

One thing I wish I could argue is the resolution argument. I should be able to figure out how big a pixel is fairly easily. Is there any documentation that a particular film (say Tri-x or FP4+ or whatever) has a certain sized grain? If I find the size of grain, I guess I could make a comparison of the 'possible resolution' of a film vs a digital sensor. I know the camera lens, enlarging lens, tripod stability, and such affect resolution, but at least I'd be able to give an answer to the inevitable question "is film better than digital?" with terms of resolution.

the reason I look for something like this is people dont seem to accept the answer "I like film better." They seem to want an objective answer. At least I'd be able to compare film resolution to digital resolution in a way most people can understand, even if the film grain vs pixel isnt a perfect analogy.


OK, what I'm getting at is "is there any documentation of the size of film grain of a particular film?" I know film grains between films of the same iso ratings wont be exactly the same size , but shouldnt there be a document saying "Ilford FP4+ film is X size" and "Kodak TMZ is Y size"? I'm horrible at google searching, so I've probably looked right over the thing I'm looking for without even realizing it...

BTW, I'm not trying to start a film VS digital debate. Those things actually piss the hell out of me (kinda like the rival sports team crap I have to deal with all the time in Lawrence county, Alabama). I'm looking for real technical info on film grain size. I can figure out pixel size for a particular digicam myself or find it in a more appropriate place.

Braces for shitstorm.... :munch:
 
OP
OP

Existing Light

Member
Joined
Sep 30, 2009
Messages
457
Location
Huntsville,
Format
Multi Format

Kevin Caulfield

Subscriber
Joined
Aug 3, 2004
Messages
3,845
Location
Melb, Australia
Format
Multi Format
From previous discussions here and elsewhere ... Ball park, for a 100 ISO film, MF, 6 x 6 or so, you have a resolution of maybe anything from about 20 to 50 MP.
 

clayne

Member
Joined
Sep 4, 2008
Messages
2,764
Location
San Francisc
Format
Multi Format
Pixels and grain are not the same beasts. Grain is not necessarily binary.
 
OP
OP

Existing Light

Member
Joined
Sep 30, 2009
Messages
457
Location
Huntsville,
Format
Multi Format
clayne said:
Pixels and grain are not the same beasts. Grain is not necessarily binary.
Click to expand...

I know. But they should be similar enough in terms of resolution that I can make a reasonable analogy like "your Nikon Dwhateves has W pixels, which means they're X big in measurement while the grains of PlusX are Y big in measurement, which means there's about Z grains in a 35mm negative." That wont be a perfect example because grains arent in a flat grid but suspended in an emulsion, but comparing pixel size to grain size should give a reasonable comparison.

That can at least be as objective of an answer as you can give one of those people that want to know about film vs digital in reguards to resolution. I think it beats "I like film better because it's got a look that digital cant replicate." I mean, I believe that's true, but it's still subjective.

I feel this thread disentegrating very soon :\
 
OP
OP

Existing Light

Member
Joined
Sep 30, 2009
Messages
457
Location
Huntsville,
Format
Multi Format

henpe

Subscriber
Joined
Mar 13, 2008
Messages
106
Location
Sweden
Format
Multi Format
When making comparisons with sensor chips, one should also take into account the Bayer-filter and the fact that a pixel is not sensitive to all three RGB-primaries. On a x-megaPixel camera, little more than a third of the pixels are green sensitive, little less than one third is blue and red sensitive, respectively. The full-color x-megaPixel image is generated through interpolation. The effective resolution is thus less than x mega pixel. Also, If I have understood things correctly, the MTF of a sensor chip has a much more steep cut-off, while a film degrades more gracefully beyond the MTF cut-off. This, I think, influence how the media respond to (too-)fine details.
 

paul ron

Member
Joined
Jan 22, 2004
Messages
2,706
Location
NYC
Format
Medium Format
Ah come on, instead of dancing around the measurements with resolution comparrisons n chip sensors, how about just giving a size in microns or whatever the average single grain measures for both conventional film n T-grain films?

Perhaps this would be better posted in the Silver Gelatin Based Emulsion Making & Coating area where the real scientists live?

.
 

henpe

Subscriber
Joined
Mar 13, 2008
Messages
106
Location
Sweden
Format
Multi Format
I believe 'mega pixel' is an insufficient measure to measure resolution, as it all depends on e.g. the physical size of each pixel, how big the sensor chips is, and how the pixels are distributed on the chip area. For the same reason, I argue that the size of a grain is an incomplete measure of a films resolution. There is no way to calculate a MP-equivalent for a particular film, without having to introduce a lot of boundary conditions.
If one need to argue about the resolution of chips compared to films, I believe the best approach is to compare MTF-curves.
 

RalphLambrecht

Subscriber
Joined
Sep 19, 2003
Messages
14,564
Location
K,Germany
Format
Medium Format
ilm resolutions sre well documented, and they exceed sensor resolutions by far, but they are based onwell-lit high-contrst targets.in th beginning of the digital craze, it was said that a digital camera would need 60 mpixels to compete with film, but i don't know te details of that claim.
 

stavrosk

Member
Joined
Jun 10, 2011
Messages
153
Format
35mm
I have yet to understand why people think resolution is the most important thing. I know I am going slightly off topic but how can anyone care about resolution when the dynamic range and the colours are not as good.
I dont care if I have a 16MP sensor when the highlights are blown.
Also the resolution of film is irrelevant as the resolution of the scanner is what matters.
 

tomalophicon

Member
Joined
Feb 7, 2010
Messages
1,568
Location
Canberra, AC
Format
Sub 35mm

You mean the paper, right?
 

clayne

Member
Joined
Sep 4, 2008
Messages
2,764
Location
San Francisc
Format
Multi Format

Well the whole point is that they are not the same. They are not apples and apples - which is why a desire to objectify them into the same thing will ultimately fail, except for the most simplistic and vague of comparisons.

And it is for that same fundamental difference in mediums that we continue to use this analog medium.
 

paul ron

Member
Joined
Jan 22, 2004
Messages
2,706
Location
NYC
Format
Medium Format
Resolution has noting to do with the actual size of a grain in film. Resolution is a reference to detail, how much information there is in an image, sharpness; such as line tests used for testing lenses' resolving power.

http://en.wikipedia.org/wiki/Image_resolution

So without all the fluff does anyone actually know how big a grain is?

.
 

Athiril

Subscriber
Joined
Feb 6, 2009
Messages
3,062
Location
Tokyo
Format
Medium Format


Demosaicing works, it's not so much interpolation as one might think, it's interpolation for colour. High resolution, eg high spatial frequencies in the real world occur mostly over lumninance and not chroma, it has full or close to full luma resolution, though demosaic'ed chroma still does a lot better than images that have been chroma sub-sampled (eg; even high end video, digitised motion picture).



I like resolution, but line tests.. good for some things, like determining if your lens is a good copy, or what is going to satisfy you for your intended purpose. In any case film resolution is variable, most high spatial frequencies are going to occur over lower contrast, so low contrast resolution is what I find important, I don't bother with the high contrast res in making a determination of what I should be using for what if I do indeed need detail.

If you're doing astrophotography with ridiculously good equipment, then film would be a good choice with it's high resolution over high contrast.


Velvia 50 for example is 80 lp/mm over low contrast according to the data sheet.. however the numbers manufacturers state don't always seem to line up with the MTF charts published, where some films outperform others on the MTF but are rated lower than a film.

Velvia 50 is then also 160 lp/mm for high contrast, T-Max 100 has 63 lp/mm for low, and 200 lp/mm for high.

On the MTF charts, T-Max 100 looks like it hits 200 lp/mm @ 25-30% response, which 63 lp/mm looks like it's hitting 90%+

Velvia 50 on the other hand looks like it hits 80 lp/mm @ 20%, and 200 lp/mm @ 7%. Though it is a high contrast film.



Anyway the maximum information a 5DII size file can store is 78 lp/mm. So in theory you can best the 5DII with Velvia 50 in 35mm format (assuming everything is allowing you to... subject, lens, exposure, processing, etc) at the lowest of low contrast areas of the subject, and then proceed to grow in resolution the higher the contrast gets over high spatial frequencies.

At maximum contrast, theoretically, you could get 4x the maximum theoretical information a 5DII could store with Velvia 50 in only 35mm.

Practise is different and is all over the place of course.
 
Last edited by a moderator:

paul ron

Member
Joined
Jan 22, 2004
Messages
2,706
Location
NYC
Format
Medium Format
Last edited by a moderator:

Athiril

Subscriber
Joined
Feb 6, 2009
Messages
3,062
Location
Tokyo
Format
Medium Format

paul ron

Member
Joined
Jan 22, 2004
Messages
2,706
Location
NYC
Format
Medium Format
WRONG, he is asking for grain size.. not resolution!

OP original question....

[B]OK, what I'm getting at is "is there any documentation of the size of film grain of a particular film?" I know film grains between films of the same iso ratings wont be exactly the same size , but shouldnt there be a document saying "Ilford FP4+ film is X size" and "Kodak TMZ is Y size"? I'm horrible at google searching, so I've probably looked right over the thing I'm looking for without even realizing it...

BTW, I'm not trying to start a film VS digital debate. Those things actually piss the hell out of me (kinda like the rival sports team crap I have to deal with all the time in Lawrence county, Alabama). I'm looking for real technical info on film grain size. I can figure out pixel size for a particular digicam myself or find it in a more appropriate place.[/B]
 

clayne

Member
Joined
Sep 4, 2008
Messages
2,764
Location
San Francisc
Format
Multi Format
What's the point when both grain SHAPE AND SIZE is not regular or even in the same plane?

Hairshirt discussion.
 

paul ron

Member
Joined
Jan 22, 2004
Messages
2,706
Location
NYC
Format
Medium Format
I quoted the original question below my answer.... did you read it?

Once again for you reading imapared... The origianl quoted question by the OP....



OK, what I'm getting at is "is there any documentation of the size of film grain of a particular film?" I know film grains between films of the same iso ratings wont be exactly the same size , but shouldnt there be a document saying "Ilford FP4+ film is X size" and "Kodak TMZ is Y size"? I'm horrible at google searching, so I've probably looked right over the thing I'm looking for without even realizing it...

BTW, I'm not trying to start a film VS digital debate. Those things actually piss the hell out of me (kinda like the rival sports team crap I have to deal with all the time in Lawrence county, Alabama). I'm looking for real technical info on film grain size. I can figure out pixel size for a particular digicam myself or find it in a more appropriate place.[
 

Athiril

Subscriber
Joined
Feb 6, 2009
Messages
3,062
Location
Tokyo
Format
Medium Format
You still haven't actually read the OP. Or even the part what you have quoted, and have conveniently left out much of the OP.

For the reading impaired (you, paul ron), I have quoted the pertinent parts you seem to be willingly ignoring.


He want's know to the equivalent resolution, his idea is to compare grain size as resolution vs pixel size, except it doesn't work like that, the people that are capable of comprehending English and not barging in and insulting all the other people that have replied in this thread (after seemingly having replied to someone above) have been able to comprehend English and also know that grain size isn't equivalent to pixel size in a resolution argument, which is what the OP want's to know.


One thing I wish I could argue is the resolution argument.

I guess I could make a comparison of the 'possible resolution' of a film vs a digital sensor. I know the camera lens, enlarging lens, tripod stability, and such affect resolution, but at least I'd be able to give an answer to the inevitable question "is film better than digital?" with terms of resolution.

At least I'd be able to compare film resolution to digital resolution in a way most people can understand
 
Last edited by a moderator:
You must log in or register to reply here.
Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn more…