'Colour' film

[milleniummuppet]

Been experimenting with an SLR we have had for YEARS and never really used.
Its a Canon EOS 500, and as you can see - it produces some pretty interesting images.
From my best memory ( film doesn't contain any shot info ) the pic was taken 400 iso, f5.6 and 1/125.
Image was then scanned at 4800 dpi in TIFF format.

When scanning negs, the image requires a reasonable amount of pp, which can be strange coming from digital , but I would definately recomend giving it a go!

[Dave Humphries]

Hi Matt,

Was that a PP crop, or what you shot full frame, so to speak?

Interestingly I am seeing significant noise (at 400ISO) perhaps digital noise is less than film.

Cheers, Dave

BTW
There's just gotta be a "getting it from the horse's mouth" gag in here somewhere

[milleniummuppet]

Lol, yes that was full frame - shot hand-held using a 75 - 300 lens (Chasing the horse was hard work =))
I have had the same problem with digital and noise, and film is no exception.
This was scanned a very high reso however, and i THINK this was what made it easier for me.
The noise was quite bad - but only zoomed quite a way in, which made noise reduction do a great job.

I have been meaning to find out why noise is grater at higher iso's , does any one have a good answer as to why?

[iPhillip]

Heres a quick simple summary (as clumsy as my explanations can be)..

As you increase your ISO the more sensitive your sensor or film becomes to light. As the sensor becomes more sensitive this amplifies the light in the frame etc, much the same as turning up the volume on your speakers - ISO just amplifies the noise within the image. The orgin of the noise is coming from within the sensor, I think its like light witch cannot be attributed to any source or subject (not sure about this).

[Dave Humphries]

Hi Matt, Phillip,

I'd call it "output" that cannot be attributed to any source or subject, rather than light, but other than that the definition is reasonable. In either digital sensor or film emulsion, you are amplifying it more to recover the required "light recording" (or image), so the noise is more troublesome.

Just like hiss and hum on your Hi-Fi/Stereo amp and speakers (or whatever they're called these days), if there's loud music, you don't notice it, but if it's quiet - between tracks (or in picture terms, bland and lacking variation), you do notice it more.

For more, read Sean tutorial; https://www.cambridgeincolour.com/tu...mage-noise.htm

Cheers,

[milleniummuppet]

Yea, that's how I understand digital noise, but I was really meaning film.
It works a lot differentially, because sometimes you can use a 400 film and get next to no grain.
Night photography can produce more noise - but why is that? sometimes you can use a 100 film and long shutter at night AND still get noise.

Its definitely complicated, is there anyone who's an expert at explaining it simply =).

[Dave Humphries]

Hi Matt,

Although it is different, I would actually argue it's more similar than you might expect.
Film "amplification" can happen when you process the roll of film, if you know you have "pushed" it; i.e. underexposed the whole roll by say, two or more stops*, then you can 'cook' it i.e. leave in the developer for longer to compensate and this is primarily what brings out the grain.
If you don't over develop, you'll end up with really 'thin' negatives, almost transparent and the consequence is a very short print exposure.
For transparency (slide) film, it'll be the opposite of course, a very dark slide.

If a roll of film has been overexposed, it can also be under developed, not recommended, but this may improve grain.

* less for transparencies as the film has less latitude to incorrect exposure.

I'm reaching the limit of my memory and theoretical knowledge so I'll stop (hopefully) before I say something really silly.

Cheers,

[iPhillip]

Yea, that's how I understand digital noise, but I was really meaning film.
It works a lot differentially, because sometimes you can use a 400 film and get next to no grain.
Night photography can produce more noise - but why is that? sometimes you can use a 100 film and long shutter at night AND still get noise.

Its definitely complicated, is there anyone who's an expert at explaining it simply =).

In digital, noise can be amplified (like it is with ISO ratings) with long exposures, or multiple long exposures due to build up of heat in the sensor.

On film, grain is purely due to the chemical reaction between the emulsion and the developer. If you have a weak developing solution the chemical reaction is less violent over a longer period of time you get less grain. Whereas a short developing time with a strong dilution of developer takes less time to develop properly but the reaction is aggressive and creates more grain.

[milleniummuppet]

[On film, grain is purely due to the chemical reaction between the emulsion and the developer. If you have a weak developing solution the chemical reaction is less violent over a longer period of time you get less grain. Whereas a short developing time with a strong dilution of developer takes less time to develop properly but the reaction is aggressive and creates more grain.[/quote]

I'm pretty sure that's specific to B/W film.
Colour is different, its something to do with the specific components of the film ( not silver emulsion like B/W ).
Apparently the development time and chemical concentration will not significantly effect the 'grain' on colour film ( ask D Peirce ).
Although I still don't know why .

Perhaps the film was a little over-developed - I don't know ( I only have facilities to develop my own B/W ), but I understand about the light amplification principal.
Its just from the gist I'm getting from all of this, there is another force at work that is being over-looked that causes that reaction to some images - "Hang on a minute! there shouldn't have been that much grain! Why has that happened?"