Clipping the histogram any comments??

[5ash (Philip)]

I was looking at Tony Hitchcocks pic of corona and was pleased to see it as ive been processing my pics bearing in mind his "dont clip the Histogram rule" and was comparing them with very colourful pics currently in this forum . I viewed the histogram of Tonys image to confirm what i thought he meant and lo and behold a' lovely smooth unclipped histogram ' just like i expected. However when I checked on some of the more colourful pics being aired on this forum found some to be grossley clipped justifying by suspician that some pics are being overprocessed to give false colour etc.I myself find it hard not to get some clipping when processing which reinforces my view that you can spend too much time processing. Has anyone any comments on this matter .Perhaps a new critical term should be introduced when looking at pics like nice but overclipped
philip

[[1ponders] (Paul)]

There could be a couple of reasons why the histogram get clipped Philip. One could be because of levels adjustment during processing and that is the effect that the processor is aiming for. Another is in converting from RAW/TIFF/BMP to Jpeg, depending on the program, the conversion process may do it automatically. Photoshop and the better programs should not do this, but others will.

[Striker (Tony)]

I honestly dont know how all my images end up on final processing without going back threw them all but yes I make sure I dont clip the histogram in imagesplus...as you mentioned it was a hot topic down ay Lostock where Tony was showing us through Imagesplus.

What a guy ...onya Tony

[avandonk]

Clipping the histogram does lose infomation from an image. At the left end the histogram shows the number of pixels that carry information for the dark pixels eg near 'black' sky between objects. Conversly the right end generally shows the number of pixels which carry infomation about the blown out centers of overexposed stars. In between hopefully is information of extended objects ie nebula and dim stars. In a bid to get maximum detail and contrast in nebula sometimes the data can be stretched beyond the dynamic range of the picture type that is 8bit (256 levels) for JPG say and 16bit (65,536 levels) for Tiff. Obviously this happens far more easily for jpg than tiff. That is why you should always work with 16bit and only convert to jpg for the final image.
For some objects some clipping has an advantage but generally degrades the image if taken to far. For instance it can clean up a slightly noisy 'black sky'. If there is a lot of noise eliminating it by clipping loses real information from the objects in the image.
I can't see any real advantage to do it other than that mentioned.

Bert