No, the effect does not exist.
However, long exposures in digital have their own host of problems:
Sensor overheating. This used to be a bigger problem, but with the advent of video DSLRs this has mostly disappeared.
Hot pixels. Some sensors just don't like staying "active" and will internally leak and produce a single color hot pixel. Cameras and software ...
Essentially, no - digital sensors are pretty much linear in that if you double the number of photons hitting it, you get double the output. They're obviously not perfectly linear, but they're close enough you don't need to worry about it.
Theoretically speaking shutter speed has no impact on image colour however there are a number of side effects that can affect colour under certain circumstances.
Lighting colour temperature shifts. This occur with most AC (alternating current) lights and is typically worst with fluorescent tube lighting which swings wildly between green and ...
I don't think they directly affect the colours.
Indirectly, aperture and exposure can affect ISO. Colour saturation decreases as ISO increases.
Long exposure also heat up the sensor creating more noise, this will also have an impact on the colours.
Edited to add:
When photographing badminton games, the colours of each photo will appear to be different. ...
Cold reduces reciprocity failure, and is used particularly for astrophotography. See http://en.wikipedia.org/wiki/Photographic_hypersensitization#cite_note-15.
My own experience with Kodachrome (RIP) was that very cold weather reduced the blue-green cast of nighttime skies and cityscapes. Note that this could lead to frostbite, by the time the camera is ...
I searched for the data sheet. It is linked from the official site here:
Section 6 (Long Exposure Compensation) gives straightforward reciprocity failure details:
No exposure compensation required for exposures up to 2 seconds long
For a 4-second exposure, you need to open the aperture ...
Most film cameras have exposure times only in full stops. It is therefore easier to do the fine-tuning with aperture, which can usually be adjusted in thirds or half stops.
If you absolutely must work via exposure time you can ignore the failure up to a minute. For longer than a minute double your exposure time. When in doubt, bracket.
This may sound rough, ...
I agree with comments above and almost had nothing to add, then I remembered the highly contrasty images which are created if you use Canon 50mm 1.8 at f/1.8. I don't know how it works, but I noticed in my images as well as in other people images that very shallow apertures give this vivid look to colours in the photo when taken outdoors.
When shooting photochemical film, colours do shift at extremely short and extremely long exposures. This is called "reciprocity failure," and film manufacturers generally can recommend specific filter combinations to correct for it over certain exposure times.
With all other parameters assumed constant (as stated in the question) implies that you'll get a different exposure when adjusting just aperture size or duration of exposure, since those constant parameters include the other components of the exposure triangle you'd have to adjust to retain same exposure. An overexposure will give you more vividness in ...