Do ISO and/or shutter speed affect saturation at capture?

I'm reading contradicting information as I search about this.

I've long heard that low ISO film and low ISO sensor settings increase saturation compared with higher ISO values. I've also heard that longer shutter speeds allow color to gather in greater concentration, also increasing saturation at capture.

Are both right? Either? Neither?

I know that some films are more contrasty and saturated than others. That's not my question.

Steve - I don't think so. Camera sensors are luminance only devices with color filters on the pixels. Light of certain wavelengths is collected in the pixels and registers as a luminance value only. The only thing that's written out of the sensor is luminance at each pixel.

Now if you're talking about a RAW file, the demosaicing and color space conversion (with associated curve application) may boost saturation to some extent; But it should still be faithful to the scene - the same object shot at f/16 for 4 seconds, versus f/2 for 1/16s should show the same color - it just took longer for the pixel to collect the light in the f/16 case. As for low ISO, it may be that less noise coverts differently, or that your eye perceives saturation partly based on noise - but as long as the ISO circuitry on the chip is simply doing a multiplier (which it should be) there won't be a saturation boost.

I would guess that where sensors seem to create saturation is because a properly exposed shot in low light would tend to be brighter, and more saturated, than what your eye sees. Human eyes start to go into sort of B&W mode and the rods and cones trade off in low light, so you definitely don't perceive bright colors. So a dim light shot, exposed to look more like daylight (or even just to have the detail your eye perceives) will probably be more saturated than what you see.

These may be inaccurate reports about exposure. Under-exposure may result in more saturated colors (more exposure means more light is gathered and results are brighter and may initially appear washed out). When using film this was a good way of boosting color in some situation but I wouldn't recommend it for digital photography since it may also result in noise and loss of detail. Saturation is so easy to adjust/correct post-exposure that it really doesn't make sense to sacrifice image quality to get more saturation in the initial capture.

Guy

Thanks, guys. I appreciate the fast responses, even though I lost a bet because of them.

Just goes to show you can't trust everything you read. As though I didn't already know that.

Just goes to show you can't trust everything you read. As though I didn't already know that.

Unless of course, you see it on TV - then it must be true.