# Clipping: LR recovering vs. true clipping



## Hoggy (Oct 1, 2015)

Hey all,

This has been bugging me on the back burner for a very long time now and many searches at various times have turned up nothing conclusive.

What I'd like to know is if anybody knows for sure...  When LR indicates clipping - either via alt-sliding on basic panel adjustments like blacks and whites, or the clipping indicators in the histogram - when it's one of the various colors other than black or white...  Is LR at that point reconstructing data based on the values of the channels that _aren't_ clipping?  Or are the various channels actually being clipped/'lost' at that point?
...  And is that any different for when the clipping indications show black or white.

Trying to be clearer..  I've read that LR can reconstruct clipped data based on the values of the raw channels that aren't clipped.  So I'm wondering at precisely what point is the data truly being 'lost' (as if a print/JPG were to be made at that point) vs. LR doing reconstruction 'behind the scenes' (so as to show some detail if a print/JPG were to be made).

Plus I'm curious if the answer would be any different if using the prior process versions of 2003 or 2010.  Not that I really plan on using them, but I'm curious nonetheless.

Thanks.


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## Tony Jay (Oct 1, 2015)

Hi Hoggy!

This is actually a very good question that does cause a lot of confusion.

Lets start with an easy example:
Put a raw image into Lightroom that has very little contrast.
As is the histogram shows that nothing is blown - all well and good.
Now increase contrast and/or overall exposure.
It is likely at some point that the histogram will show either blown highlights or clipped shadows.
However, it makes perfect sense that the raw image has no clipping.

A somewhat different example:
A high contrast raw image shows all three channels show some clipping in the highlights when loaded into lightroom.
Does this mean that the highlights are blown?
Maybe, maybe not!
My suggestion is to haul back on the highlights slider and see what happens.
If nothing is truly blown then pulling back on the highlights then the heaped up highlights will change shape and move toward the midzones.
If all or part of those highlights truly are blown then at least some of the highlight peak remains and even if the actual tonal values can be pulled done below 255,255,255 the tones stay a shade of grey.

Onward and upward.
If one or two channels are recording 255 this does not necessarily indicate an issue.
The brightest pure red recordable is 255,0,0.
If what you were shooting really needed to be that colour red that is not an issue.
If in fact what you were shooting was a little less than that intense red then pulling back on the red saturation slider will fix that.
If however there were several different pure high-end red tones and the camera recorded them all as 255,0,0 then none of that tonal diversity will survive.

If however the reds in the above example are not pure and have green and or blue components that are not blown then some distinction is still possible when the overall tonality or red saturation is pulled back.

With respect to the different process versions 2012 seems both the easiest to use and arguably does the best job in rescuing potentially blown highlights (and clipped shadows).

A quick dive into raw versus JPEG.
JPEG's are 8-bit files and so both tonal information and colour data are limited compared to raw files.
Complicating issues of colour are colorspaces.
The working colorspace in Lightroom is ProphotoRGB.
This is a very large colorspace - much bigger than either AdobeRGB or sRGB that are the usual output colorspaces for JPEG's.
In fact - good softproofing can usually ameliorate any problems however it is prudent to point out that all the way through the photographic process from lining up a shot all the way through to the output - either a print or a displayed image on a monitor etc data is lost.
The trick is to manage this data streamlining that takes place.
This is what understanding the entire digital workflow and colour management is all about.

The best summary statement is to say this: photography is a visual art - if it looks good then it is good no matter what the numbers say.
I know my way around digital photography rather well these days and I know how to manipulate the "numbers" just fine but all I am looking for is a good visual result.

I know that there is more to say on this subject but, for the  moment at least, lets leave it at this.

Tony Jay


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## Hoggy (Oct 3, 2015)

Tony Jay said:


> If one or two channels are recording 255 this does not necessarily indicate an issue.
> The brightest pure red recordable is 255,0,0.
> If what you were shooting really needed to be that colour red that is not an issue.
> If in fact what you were shooting was a little less than that intense red then pulling back on the red saturation slider will fix that.
> ...



I understand all that, but that's not entirely what I'm trying to get at (coupled by my very real difficulty in trying to express/word it).  And it _is_ mostly academic..  I'm sure that will still help others though - and you _have_ given me a better idea on how to word what I'm trying to get at.

ok, so...  Excluding colorspace conversions and softproofing, and the differences between raw-clipped data and adjustment-clipped data..  And going off of the above quoted situation...

It makes more sense to me now that when the 'alt' preview shows either pure black or pure white, that LR is trying to indicate that those are indeed being clipped in it's current [adjusted] colorspace (Melissa/ProPhotoRGB with sRGB tone curve for display -- yeah, I just looked it up again for a refresher  ).  .....  So, if one is to go off of the above quoted situation:  When LR shows a *color* in the 'alt'/clipping preview..  Is that the point in which the adjusted colors have now been clipped, or is that the point at which LR is still actively trying to reconstruct colors (putting aside raw-clipping issues)?


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## Tony Jay (Oct 3, 2015)

Hoggy said:


> I understand all that, but that's not entirely what I'm trying to get at (coupled by my very real difficulty in trying to express/word it).  And it _is_ mostly academic..  I'm sure that will still help others though - and you _have_ given me a better idea on how to word what I'm trying to get at.
> 
> ok, so...  Excluding colorspace conversions and softproofing, and the differences between raw-clipped data and adjustment-clipped data..  And going off of the above quoted situation...
> 
> It makes more sense to me now that when the 'alt' preview shows either pure black or pure white, that LR is trying to indicate that those are indeed being clipped in it's current [adjusted] colorspace (Melissa/ProPhotoRGB with sRGB tone curve for display -- yeah, I just looked it up again for a refresher  ).  .....  So, if one is to go off of the above quoted situation:  *When LR shows a color in the 'alt'/clipping preview*..  Is that the point in which the adjusted colors have now been clipped, or is that the point at which LR is still actively trying to reconstruct colors (putting aside raw-clipping issues)?


Thats the colour that is clipped.

Tony Jay


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## Johan Elzenga (Oct 3, 2015)

I probably don't understand your question, but I think it's pretty simple. If Lightroom shows you a clipping warning it simply means 'if you don't change anything to these settings, these pixels will get clipped'. The colors tell you if this means clipping of all channels (white) or clipping of one or two channels (color). If Lightroom _can_ reconstruct the colors in a certain channel then you don't see a clipping warning (because there won't be clipping).


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## Hoggy (Oct 3, 2015)

JohanElzenga said:


> If Lightroom _can_ reconstruct the colors in a certain channel then you don't see a clipping warning (because there won't be clipping).



Ahh, OK!  That's *precisely* what I was after, which Tony also confirmed (and got me to reread a Lightroom RGB pdf).  I _do_ have serious issues with mental clarity - I eventually do get there, but it might take a bit.

Thanks a lot guys!  FINALLY, a long time back-burner question/curiosity of mine has been confirmed! :nod:


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## Tony Jay (Oct 4, 2015)

Well done Hoggy, we are all learning - ever onward, ever upward.

Tony Jay


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