Background, this thread: https://www.cloudyni...onger-exposure/
The OP was asking if their 0.001" bias frame from an ASI183 CMOS camera was "good".
Bias frames are designed to be the constant electronic signature of the sensor, with no dark current. They are the part that should always be subtracted from all frames that come off the camera.
Dark frames contain both the bias and additional dark current that accumulates from the sensor being active.
When dark-scaling it's useful to differentiate between the electronic signature and the dark current produced noise from the sensor. However, I'm not aware of anyone dark-scaling with most of todays most used cooled cameras.
So why do we even talk about bias frames anymore? Why add a level of confusion about what the difference between a dark, a bias, and a dark-flat, flat-dark is?
Why not just say: "Each and every light and flat frame that comes off the camera should be subtracted by a dark of reasonably same characteristics as the light"?
If you have a light of 300 seconds, you subtract a dark of 300 seconds.
If you have a flat of 0.1 seconds, you subtract a dark of 0.1 seconds.
No bias, no dark-flats, just darks.