# ProPhoto to sRGB clipping problem.



## LightKhan (Jun 1, 2013)

I've been having this problem for quite a long time, only having been procrastinating finding a solution because my usage of sRGB is a subsidiary one. My workflow is mainly targeted at printing/archiving and, as such, 16-bit, ProPhoto is usually all I care for.

...but now I've decided to enter an online contest, one that requires 8-bit, sRGB Jpegs as the submission format, and it is critical I get these from my Tiiff "masters" as technically good as possible.

The problem: When converting from 16-bit, ProPhoto Tiffs into 8-bit sRGB Tiffs or Jpegs (for export, for instance) the original unclipped histogram gets clipped at both ends, be it single or multichannel clipping. 

How can I avoid this (...or, at least, control it by reducing clipping to a minimum)?

For instance, the working color space in LR is ProPhoto RGB. Is there a way to natively work within LR with sRGB?

(I searched for a reply to this problem but all I could find was a proposed solution for the same problem but as applied to Camera Raw in PS, not LR)

Thanks.

LK


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## erro (Jun 1, 2013)

ProPhoto RGB is a much larger color space than sRGB. If you have colors in your ProPhoto RGB image that are more saturated than sRGB can handle, then you will get clipping. You will have to reduce the saturation so that it fits in sRGB.

I haven't realyy worked with these things myself, but LR 4 has a "proof view" where you should be able to select sRGB as your simulated output space, and see how your ProPhoto RGB image will look. And be able to adjust it until it looks decent enough in sTGB.


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## Jim Wilde (Jun 1, 2013)

Yes, you could try the "soft proofing" option in the develop module....assuming you are using LR4 of course. Updating your profile would help, as then we can often provide more targeted support without having to query your setup first.


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## LightKhan (Jun 1, 2013)

Ok...I understand "why" it happens...my question was more around how to have a real-time histogram representation of how things look in sRGB.

You guys helped a lot. It is, indeed, possible to select "Soft Proofing", sRGB and then select "Create Proof Copy" from the pop-up dialog box. 

A copy will then be created and all alterations made to it will be reflected, in a real way, in the histogram.

I now have a dilemma: Bringing the colors back "into" the lower gamut histograms, during the initial "development" from Raw accounts for a "meh" photo, with the colors and contrast fully diluted is sRGB.

Am I better off with this base conversion from Raw and then trying to give it some "punch" back in PS (...not that effective...) or do you guys feel it is better to just work in ProPhoto and "accept" the better looking, clipped sRGB version resulting from the space conversion? 

Are people who may analyze the sRGB histogram going to be able to discern that the clipping is coming from the color space conversion?

Thank your continued help.

LK


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## LouieSherwin (Jun 1, 2013)

Hi,

Sounds like you probably have images with highly saturated colors. As previously mentioned the sRGB color space has quite smaller gamut than Photo Pro or even Adobe RBG. The best way to deal with these conversions, I believe, is to let the color management system do all the work. But as you state Lightroom is not doing a very good job and unfortunately Lightroom does not give you access to the some of the needed controls. What you probably want to do is have the conversion  use the "Perceptual" rendering intent but Lightroom only gives you access to this in the Print module not in the Export module.

If you have Photoshop I would do the conversion to JPG there and play with the rendering intents when you do the color space conversion. If you don't have Photoshop try printing and saving a full resolution image to JPG and try to the two rendering intents available in the Lightroom Print module to see which one looks best. 

If you are satisfied with your prints then you should not have a problem getting a decent sRBG JPG from the same image as the printer gamut is even smaller than sRGB. In any case converting wide gamut images to smaller gamut color spaces always involves some compromise it's just a matter of finding the most pleasing outcome.

-louie


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## LightKhan (Jun 1, 2013)

Hi Louie,

I don't have any problems with printing as all my workflow is in ProPhoto which is then transcribed into custom profiles for the required papers to be printed in my Epson Stylus Pro 3880. Both PS and LR let me "proof" the final result and only marginal inability to render in print is usually displayed. My A2 prints look gorgeous and match exactly what I see in my calibrated Eizo.

The problem I am dealing here is how to transcribe my 16-bit ProPhoto RGB Tiffs into 8-bit sRGB Jpegs, for submission to a contest, without either (1) rework all the submitted photos from scratch starting from an initial sRGB 8-bit conversion from Raw (they will then lose their "punch") or (2) simply transcribe the ProPhoto RGB colorspace into sRGB, in PS, and having my histogram look like it was submitted to amateur PP.

Thanks!


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## Tony Jay (Jun 1, 2013)

Hi LightKhan,

Part of the answer to your dilemma has already been provided - that is to softproof in Lightroom using sRGB as the profile.
Your question now is how to edit the image to get an acceptable result (if I have understood correctly).

Firstly, do not rework your images from scratch - there is no need (more on this shortly).
Also do not simply change the export colourspace from ProphotoRGB to sRGB and leave it at that - most if not al of your images will look rather strange if you do that (you do want to do well in this competition do you not?).

So how can this be done?
Firstly, if you are working from Lightroom any suggestion that Photoshop is required for an excellent result betrays a lot of misconceptions about both Lightroom and Photoshop.
Frankly, if you are the world's best exponent of Photoshop, like Jeff Schewe for example, you can use it and get a good result.
However, even if you are Jeff Schewe, it is much easier and simpler just do do the job in Lightroom and get an equivalent or better result.

So, what to do:
All the images that you intend submitting to this competition I would make virtual copies of.
I am assuming that the original images are in the condition that you would want to print for maximium effect.
The virtual copies are the ones that you should use now to prepare them for 8-bit JPEG sRGB export.
This preserves the master copies in their original states for other purposes (phew!, no remastering from scratch required).

Using the virtual copy go into softproofing mode.
The profile that is required is sRGB.
All the issues that you mention previously about colours going out of gamut and will occur.
The only question now is how to deal with the out of gamut colours.
Use the original master image as your guide - put it up side by side with the virtual image on your monitor.
The 'create proof copy' subpanel that sits just under the histogram gives you two options with regard to rendering intent: perceptual and relative.
The choices you make determine how the out of gamut colours will be brought back into gamut.

Relative colorimetric rendering is simple: any colour that is out of gamut will be mapped to the nearest colour point that is in gamut.
So if you have an image of a flower whose petals have several delicate and closely related hues of yellow that are out of gamut then all those hues will be mapped to the same colour meaning that a block of solid colour will result.
Perceptual rendering will deal with the situation above quite differently: All the hues that are out of gamut will be moved to in gamut hues however the relationship between those hues will, as best possible, be preserved so a solid block of colour will be avoided.

From the description given above you may well think that perceptual rendering will always be the default for every image but this is not so.
It is always a horse-for-courses situation and I would closely scrutinize any image with both perceptual and relative intent selected to make a decision as to which may be best.

Both tonal relationships as well as colour in your image will likely require adjustment and the entire toolset of the Devlop module is there for you to use. Use the master image for comparison to achieve a result that is as close as possible to how the master looks.

When you have finished softproofing the virtual copy export it using the export dialog selecting JPEG and I assume the highest quality, and sRGB (as the colourspace).
How you output sharpen depends if the image will only be projected on a screen for judging or whether it is to be printed for judging. I don't know for sure but if they want an image in the sRGB colourspace it is more than likely that it is for projection. In that case tick 'sharpening for' and then select 'screen' and then select 'standard' sharpening.
Once the export is complete view the image in a colour-managed environment and scrutinize it, not least for the sharpening effect.
You may want to to export the same image with different sharpening intensities before deciding which is the best one.

Good luck for the competition!

Tony Jay


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## LightKhan (Jun 1, 2013)

Well, I have already done that. Once I change something in the photo with "soft proof/sRGB selected, a dialog comes up with the option to create a soft proof copy, which I did (I mislead you with the expression "from scratch". I am sorry).

The thing is: In that copy, the histogram immediately shows severe clipped ends (as it probably should) but there's no way to fiddle with the Develop controls to tame that clipping that does not also makes the photo then look absolutely "bland", without punch.

...I am a bit lost on this one...



LK


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## Tony Jay (Jun 1, 2013)

LightKhan forget about the histogram - ignore it.
Compare your master to the virtual copy side-by-side - concentrate on making the virtual copy (in softproof mode) look like the master - when you have achieved that the job is done!

Tony Jay


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## Tony Jay (Jun 1, 2013)

Addendum: The actual process is identical, in principle, to preparing an image for printing.
Obviously, because the actual output media and therefore the profiles used and output sharpening is different the details of the process need to take this into consideration.
*The key is to make the virtual copy resemble the master as closely as possible*.

Second addendum: To help with the understanding of the softproofing process it is important to understand that when an image is in softproofing mode it will simulate the final output state, either a print with a particular paper/printer combination, or in your case projection in the sRGB colourspace. So, if the image in softproofing mode looks good (the guide will be the master copy) - good and well. If, bluntly, it looks like crap (it doesn't look like the master copy), then fix it. This is the whole point of softproofing.

Tony Jay


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## LightKhan (Jun 1, 2013)

Thanks for your guidance, Tony.

So, if you were a juror in a competition and checked the histogram for an entry, saw it significantly clipped at both ends, you would find it (independently of any visual merits it might have), technically OK?

LK


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## Replytoken (Jun 1, 2013)

LightKhan said:


> Thanks for your guidance, Tony.
> 
> So, if you were a juror in a competition and checked the histogram for an entry, saw it significantly clipped at both ends, you would find it (independently of any visual merits it might have), technically OK?
> 
> LK



Please forgive me for asking, and please forgive my ignorance about competitions, but do juries really check histograms?  I could imagine if this was a technical contest, but do they do so for photo contests (assuming this is a photo contest)? 

--Ken


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## Denis de Gannes (Jun 2, 2013)

Surely the judges would be judging the visual quality of the Prints presented, as opposed to the image files on screen?


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## Replytoken (Jun 2, 2013)

Denis de Gannes said:


> Surely the judges would be judging the visual quality of the Prints presented, as opposed to the image files on screen?



This was my thought, but then again, I do not enter my photos in competitions so I did not want to make assumptions.

--Ken


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## Tony Jay (Jun 2, 2013)

Whether the jury is looking at an actual print or a projected image it is only the image itself that is judged.
Either way the softproofing process should give a good result - yes.

BTW several competitions are only judged by projected images and not by prints.

Tony Jay


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## LightKhan (Jun 2, 2013)

This is a electronic-files-only competition. 

I guess I'm being over-zealous and I now gather there's no way to avoid the histogram end spikes after conversions.

Thank you all for your time and much appreciated input.

LK


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## erro (Jun 2, 2013)

A clipped histogram doesn't neccessarily mean there is something wrong with an image. Sometimes you have completely blown out whites. Or pitch black shadows. There is no universal rule that say you must have a certain look of the histogram. Unless the competition rules say so, but then those are strange rules. The only thing that matters (or should matter) is the visual appearance of the image. Clipped histogram due to bad color space conversion on the other hand is something different, and could well be noticed and seen as something bad, even without looking at the histogram.


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## LouieSherwin (Jun 2, 2013)

LK,

Andrew Rodney, a recognized expert in color management theory and practice, has a great site DigitalDog with a number of excellent tutorials. Of particular relevance to this discussion are the following two. The first is a quick overview and the second takes a practical look at soft proofing in LR4 explaining the benefits and limitations. He shows how, as Tony has described, how to make use of virtual copies to make adjustments specific to your target output color space. He also gives a clear example showing why it is not advisable to try adjust out the color clipping in Lightroom but rather let the the color conversion handle that part for you.

Lightroom 4 and soft proofing video
Lightroom 4 and soft proofing video part 2

I found it valuable to watch both of these again and refresh my understanding of these issues.

-louie


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## LightKhan (Jun 2, 2013)

Thank you Louie. I will check it for sure.

What an extraordinary support resource this forum is 

LK


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## LightKhan (Sep 26, 2013)

OK....I have to resurrect this as I have hit a wall, it seems.

I have this photo with prevailing highlight reds, yellows and oranges. It is not clipped in ProPhoto RGB (my working space in PS). When I convert it to sRGB the issuing clipping, as the colors are redistributed into the much smaller gamut, makes for a LOT of contrast detail to be lost.

As per this thread, I went back to LR and created a soft proof copy for the sRGB. But when a click in the "Show Destination Gamut Warning" toggle switch the WHOLE photo displays an almost-full warning. I am stumped because (1) I don't know, exactly, HOW MUCH out-of-gamut are the different areas and (2) can't figure out what to do in order to, while letting go color accuracy, at least bring the contrast detail back into the affected areas.

Can you guys provide further help?

Thanks!

LK


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## Tony Jay (Sep 26, 2013)

Hi LightKhan.
What you are describing is neither surprising nor shocking.
This is exactly the expected behaviour of changing the colour space from ProPhoto RGB to sRGB.

At the risk of repeating myself the issue is *NOT* what the histogram says per se nor whether, in this case, almost all the colour in the image is out of gamut, nor how far exactly each colour is out of gamut.

Your issue, simply and irrevocably, is to make a great looking image within the confines of the sRGB colourspace.
The way to do this, IMHO, is to use the master image that is still in the ProPhoto RGB colourspace for comparison.
Your guide to the edits that are required are informed by your aesthetic and artistic taste NOT mathematics and science.
As long as the image, in the sRGB colourspace, looks good once edited nothing else matters.
By definition the sRGB image *cannot* look exactly like the ProPhoto master unless the gamut spread of the master was so limited to start with that the sRGB gamut encompassed it anyway.
A close match is possible however.

Tony Jay


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## LightKhan (Sep 26, 2013)

I am afraid I've not made myself clear...

In this particular case, it seems I can not make it "look good in the sRGB color space", simply because the color remapping is massively destroying CONTRAST information and details.

Below are 2 crops of the same photo. They are "print screens" from (A) the original in TIFF/16bits/ProPhoto RGB and (B) a conversion made in PS to sRGB/8bit and saved as JPEG. Both "print screens" were then opened in MS Paint and saved as JPEGs.



View attachment 3972 





Now, take notice of the color change. That's the "expected behavior" and OK with me but why does PS crush all the contrast detail in the conversion when Paint displays the print screens (which are now *both* JPEGs) with the detail intact AND saves it like that in JPEG?

Surely there must be a way to convert in PS without that massive contrast detail loss, no?

(...In other words, If I can open my ProPhoto/16bits/Tiff file in PS, make a, say, full screen "print screen", and then open that in MS Paint, save it as JPEG and come up in that saved JPEG file with a pretty close depiction of the colors that were displayed on my screen from within Photoshop, why can't PS, itself, make a better job with "Edit"--->"Convert to Profile"?...? )


LK


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## Tony Jay (Sep 27, 2013)

So, what exactly did you do apart from changing the colourspace?

Tony Jay


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## LouieSherwin (Sep 27, 2013)

Hi,

I think that Tony is correct in stating the your difficulty is due to the limitations of sRGB.

What I think you are needing are different rendering intents and I don't believe that sRGB has any or at least Lightroom which only gives you a choice of relative or perceptual only does a relative type conversion when you output to sRGB. That is why you are loosing all the detail in the saturated reds. All of the out of gamut red pixels are being placed in the same max red of sRBG. Hence the loss of detail in those areas of the image. 

Why are you converting to sRGB, use on the web or sending to a printing service? If it is for web use then there may not be much you can do as I don't know if it is possible to use a different rendering intent with sRGB even in Photoshop. If it is for a print service then this a perfect example of when you need a print service that provides a custom printer profile. 

Using the provided custom print profile you can then soft proof using different rendering intents to see which one will get the detail you want. Then convert the image to the custom profile using your preferred intent and send the resulting image to the printer. Make sure that they do not try to do any additional color conversions. 

-louie


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## LightKhan (Sep 27, 2013)

Tony Jay said:


> So, what exactly did you do apart from changing the colourspace?
> 
> Tony Jay



Nothing.


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## LightKhan (Jun 1, 2013)

I've been having this problem for quite a long time, only having been procrastinating finding a solution because my usage of sRGB is a subsidiary one. My workflow is mainly targeted at printing/archiving and, as such, 16-bit, ProPhoto is usually all I care for.

...but now I've decided to enter an online contest, one that requires 8-bit, sRGB Jpegs as the submission format, and it is critical I get these from my Tiiff "masters" as technically good as possible.

The problem: When converting from 16-bit, ProPhoto Tiffs into 8-bit sRGB Tiffs or Jpegs (for export, for instance) the original unclipped histogram gets clipped at both ends, be it single or multichannel clipping. 

How can I avoid this (...or, at least, control it by reducing clipping to a minimum)?

For instance, the working color space in LR is ProPhoto RGB. Is there a way to natively work within LR with sRGB?

(I searched for a reply to this problem but all I could find was a proposed solution for the same problem but as applied to Camera Raw in PS, not LR)

Thanks.

LK


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## LightKhan (Sep 27, 2013)

LouieSherwin said:


> Hi,
> 
> I think that Tony is correct in stating the your difficulty is due to the limitations of sRGB.
> 
> ...



I may have end up accepting it as a fact but I have a *LOT* of difficulty accepting that converting from ProPhoto to sRGB gives such poor results and, yet, when I make a screen grab from the ProPhoto image as displayed in PS, I then can end up with a sRGB JPEG copy (from copy&pasting it into MS Paint and saving that as a sRGB JPEG) that pretty much respects what was originally seen in the ProPhoto original, as displayed in the PS working area.


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## LouieSherwin (Sep 27, 2013)

Going back and rereading this discussion I see that you trying to get the best representation to be sent as a contest entry which requires sRBG, hence your frustration.

Regarding your last comment. Keep in mind that what you see in the screen capture from Photoshop is a rendering of your image through the monitor profile and that this is completely different than conversion to sRGB so I am not surprised at the difference. 

sRBG is a strange beast. Here is a brief description of sRGB over on the ColorWiki a great service provided by Chromix.com. As such it seems a poor choice for a photo contest. I would at least expect them to ask for or be able to handle Adobe RGB but that is beyond our control.

To investigate this further you could search for information or post this question on the ColorForums also provided by Chromix.com. This is a very low volume site but the only one I know dedicated to color management issues.

-louie


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## Tony Jay (Sep 27, 2013)

LightKhan said:


> Nothing.


Simply increasing contrast will cure a lot of ills in the unadjusted sRGB image.
Use whatever tonal and colour adjustments that are needed to restore the image to what you want.
The sRGB colourspace is much smaller than ProPhotoRGB and the changesin the unadjusted image, IMHO, are completely consistent and expected.

Believe me when I say this that softproofing to print on most papers delivers a result that looks worse to start with.
That is why we call the softproofing mode the "Make my image look like sh!t button."
However it is an easy thing to fix.

Tony Jay


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## sizzlingbadger (Sep 27, 2013)

LightKhan said:


> (...In other words, If I can open my ProPhoto/16bits/Tiff file in PS, make a, say, full screen "print screen", and then open that in MS Paint, save it as JPEG and come up in that saved JPEG file with a pretty close depiction of the colors that were displayed on my screen from within Photoshop, why can't PS, itself, make a better job with "Edit"--->"Convert to Profile"?...? )
> 
> 
> LK



Just a thought but the screen clipping may not be in sRGB but the monitor colour space.

What rendering intents have you tried in PS and what difference did they make ?


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## LightKhan (Sep 27, 2013)

sizzlingbadger said:


> Just a thought but the screen clipping may not be in sRGB but the monitor colour space.



Well, I am using an Eizo CG243W with is own, calibrated, profile...But, anyway, if I sweep the images to my 2nd monitor (a Dell E248WFP, also calibrated) the same "contrast crushing" is clearly visible.



sizzlingbadger said:


> What rendering intents have you tried in PS and what difference did they make ?



All 4 of them. No difference.


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## LightKhan (Sep 28, 2013)

GOT IT !!!

If I first use "Edit"--->"Assign Profile"--->"Don't Color Manage This Document" and *only then* use the "Edit" ---> "Convert to Profile" command, to convert into sRGB the color remapping occurs (as expected) but no more of that crazy "contrast crushing".

If someone can come up with an explanation as to "why", go ahead.

Myself, I am just happy I found a solution 

LK


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