Iris Nebula - spikey histogram curve.

[Ouroboros]

After applying the screen transfer function to the histogram transformation process in PI I’ve got this strange spikey histogram curve in the upper window.  I guess it’s something to do with the image having to be stretched so much in order to see the detail. Is it a problem or should I just accept it and carry on processing. 

[vlaiv]

14 minutes ago, Ouroboros said:

After applying the screen transfer function to the histogram transformation process in PI I’ve got this strange spikey histogram curve in the upper window.  I guess it’s something to do with the image having to be stretched so much in order to see the detail. Is it a problem or should I just accept it and carry on processing. 

That happens if you have 16 bit image to begin with.

Use 32bit float format for all your steps starting with calibration.

[Ouroboros]

6 minutes ago, vlaiv said:

That happens if you have 16 bit image to begin with.

Use 32bit float format for all your steps starting with calibration.

Oh, OK. How odd I never noticed this before. Maybe I did something wrong. My images are 16 bit off the camera but once in PI I always save as 32 bit XISFs.