Questions about exposing colour negative film

Ben johns

Ben johns

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I've only really used black and white film in the past but I'm starting to use a lot more c41. It seems like whenever you see people using c41 they will be overexposing it by a stop at least.
I ask as I shot a roll of Ektar recently and I had some colour casts in certain photos. The majority were correct but a couple had a slight hint of green or magenta. Im assuming thats due to my exposure being a touch too dark maybe?
 
I have very little experience with colour negative film, and zero with Ektar, so take this with a mountain of salt, because it's purely theoretical and conjectural.

Black and white films have characteristic curves, the plot of density against exposure, and they aren't straight lines. The shadows and highlights have a different gradient to the central portion. Colour films have three emulsion layers, that react to the three primary colours. And they don't necessarily have the same curves. If/when they match up, neural colour balance. When they don't, colour casts. In practice, the differences will be in the shadow areas - the region of lowest exposure. Under expose, and more of the tonal range drops into that area.

Old film may lose sensitivity more in some layers than others, and give rise to "crossed curves" which translates to different colour casts in the shadows to the highlights.

So, my guess - and it is a guess - is that this is the source of the problem. It may be possible quickly discount this explanation by looking at the published data for Ektar - if this level of detail IS published nowadays.

Just to emphasise - this is my speculation.
 
Ektar is unusual in that it is sensitive to incorrect exposures, it doesn't always make a difference, as you can tell from your roll, but it is generally considered better to get it right.
 
FishyFish said:
This might be insightful:

View: https://youtu.be/jp4eJvTBjKU
Click to expand...

Very interesting and one on how to use a spot meter..erm my Canon T90 would be a lot cheaper than the Sekonic used and can do spot metering and be used for zone settings (up to eight)..:canon: erm and :nikon:
Anyway anyone interested if you have a decent printer you can print out a Kodak grey card (I bought mine donkey's years ago) and do your own tests by metering off the grey card then metering off things in your scene and you would gain experience on what is very similar to a grey card that the light meter sees for exposure. So why? well it saves buying an incident meter for one, and if there is nothing mid grey in your scene you will know e.g. that nice blue sky or green shrubs etc etc are near to the grey card for exposure.
 
I shoot quite a bit of Ektar and never overexpose it like I do with Portra. From my experience, it’s best shot at box speed, metered with the bulb in.
I always get good feedback from the lab about the exposures, unless it’s a glaring error which I generally realise a the time.

it’s a superb film stock,IMO.

excalibur2 said:
Very interesting and one on how to use a spot meter..erm my Canon T90 would be a lot cheaper than the Sekonic used and can do spot metering and be used for zone settings (up to eight)..
Click to expand...

Whilst I get it’s a lot cheaper, I found that in my early days of shooting film, carrying a second camera around for metering was a proper chore and pretty soul destroying.
 
gazmorton2000 said:
I found that in my early days of shooting film, carrying a second camera around for metering was a proper chore and pretty soul destroying.
Click to expand...

Well I've decided to go back to the old days for a change and using a Pentax S3 and Spotmatic with screw lenses well it will include some night shots and the Spotmatic would be useless, so I'm going to take an EOS 300 camera for exposure readings...but related to your post:- the EOS 300 is so light you wouldn't know the difference in a back pack or whatever.
 
Andysnap said:
Ektar is unusual in that it is sensitive to incorrect exposures, it doesn't always make a difference, as you can tell from your roll, but it is generally considered better to get it right.
Click to expand...
Yea I did notice more change in colour than with other films. I’ve not really used that much c41, usually the cheaper stuff like c200.
 
I don't think I've ever had colour shifts with Ektar, but I have blown highlights in high contrast scenes which I haven't done when any other colour neg.
The latitude of Ektar is more forgiving than E6, but it ain't Portra (and what is).
 
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