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Author Topic: Increasing color saturation in LAB: S-curve or straight line?  (Read 8727 times)
Tim Lookingbill
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« Reply #20 on: April 27, 2013, 10:30:53 AM »
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I viewed this page in Chrome, which is not color managed.

And you're giving me tips on the technicalities of color management? Shocked

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I wonder what it would look like if originally opened in sRGB direct from Raw by a well behaved Raw converter other than LR.

As I said above, I actually edited that blue crystal switching to sRGB output space in ACR and not only did I get the same results posted in the screengrab, but attempting to get those colors back made ACR's color slider tools worthless. No adjusting could get the vibrance, luminance and hues back. To get those insane looking blues from my cheap $300 sRGB-ish Dell LCD I also used ACR's Camera Calibration Panel Saturation and Hue slider along with Vibrance, Saturation and HSL. I used all the tools.

Switching to working in sRGB in ACR greatly limited their effect.
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Jack Hogan
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« Reply #21 on: April 27, 2013, 10:40:41 AM »
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To test view Photoshop Color Picker for each of two new docs, one in ProPhotoRGB and then switch to an sRGB document. They will look drastically different. In ProPhotoRGB Color Picker select the most intense blue and fill a selection and then convert to sRGB. Turns purple even in a simple color fill.

Perhaps, but if your final color space needs to be sRGB what advantage have you had starting off in ProPhoto?  Deal with it sooner rather than later.

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The limiter editing in any color space be it Raw or Jpeg is the display. There's no such thing as twisting, distorting and squeezing color on a display....It has nothing to do with getting crazy with color in ProPhotoRGB. It's just about finding the easiest way to get all the color a display can deliver and ProPhotoRGB is the space to do it. It's that simple.

Thanks for your opinion, tlooknbill, but I'd like to see for myself, ideally with a difficult file like your blue ball one.  And so far I have not yet seen a practical advantage to going through ProPhoto when the final output space is sRGB - in a Raw file to sRGB monitor/print workflow.

In fact I have seen disadvantages to a ProPhoto working color space: sometimes I only realize that some colors are out of gamut or weird at the very end of a lengthy PP session, when I convert to sRGB just before output.  Had I noticed it before (as one would if starting off in sRGB), I may not have wasted a lot of time with fine adjustments that now would need to be undone and redone.  So unless there are some practical visible advantages to a non-pro like me, I am going to let my output device determine working color space: in 90% of the cases it's sRGB, 10% aRGB.

I am willing to change my ways on the basis of tangible evidence, which your blue ball Raw file could provide.  Care to share it?

Jack
« Last Edit: April 27, 2013, 10:48:21 AM by Jack Hogan » Logged
Tim Lookingbill
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« Reply #22 on: April 27, 2013, 10:46:32 AM »
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I am willing to change my ways on the basis of tangible evidence, which your blue ball Raw file could provide.  Care to share it?

Sure, I'll share it as long as you find me an upload sharing site other than "Yousendit.com". That site has changed since years I last used it where it now gives me a bunch of confusing information request and dialog boxes to navigate through on top of the ensuing email alerts I didn't ask for.
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Jack Hogan
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« Reply #23 on: April 27, 2013, 11:23:45 AM »
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Sure, I'll share it as long as you find me an upload sharing site other than "Yousendit.com". That site has changed since years I last used it where it now gives me a bunch of confusing information request and dialog boxes to navigate through on top of the ensuing email alerts I didn't ask for.

Grand.  If you have a gmail account you also get access to google drive.  Next to the black Gmail menu at top click on 'Drive' and sign in with your email address and pw.  Upload the file to it (you may have to .zip it, I can't remember), set sharing to 'anyone who has the link' and copy/paste the link here.  Alternatively Microsoft sky drive.

Jack
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Tim Lookingbill
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« Reply #24 on: April 27, 2013, 11:31:46 AM »
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Grand.  If you have a gmail account you also get access to google drive.  Next to the black Gmail menu at top click on 'Drive' and sign in with your email address and pw.  Upload the file to it (you may have to .zip it, I can't remember), set sharing to 'anyone who has the link' and copy/paste the link here.  Alternatively Microsoft sky drive.

Jack

I have a yahoo email account. Will that suffice? I'm not opening a Gmail account for this.
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Jack Hogan
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« Reply #25 on: April 27, 2013, 11:40:46 AM »
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I have a yahoo email account. Will that suffice? I'm not opening a Gmail account for this.

Don't think so.  I have sent you a private message with my email address.  If you mail it to me I'll share it with the group.

[EDIT] Here is Tim's Blue Ball file: https://docs.google.com/file/d/0BzGif7iQ1sgla090XzNGT0p0M2c/edit?usp=sharing
« Last Edit: April 27, 2013, 12:04:04 PM by Jack Hogan » Logged
digitaldog
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« Reply #26 on: April 27, 2013, 11:49:17 AM »
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Perhaps, but if your final color space needs to be sRGB what advantage have you had starting off in ProPhoto?  Deal with it sooner rather than later.

In my workflow, it would be the master RGB space, sRGB is just an iteration to send to the web (where as you've seen, folks with non color managed browsers might be viewing the image. IOW, the old wild west of color <g>).

Short of screen viewing on the web, sRGB has no use for a sophisticated user who's starting their process with raw! So don't throw the baby out with the bath water even if one of your output goals is sRGB to the web. For print, the only time sRGB is useful is when you're handing that data off to clueless end users.
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Andrew Rodney
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Tim Lookingbill
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« Reply #27 on: April 27, 2013, 11:57:19 AM »
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Don't think so.  I have sent you a private message with my email address.  If you mail it to me I'll share it with the group.

Check your email, Jack. I sent it through my yahoo account as an attachment. Let me know if you got it or whether or not you want to proceed by this method of file transfer.
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new_haven
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« Reply #28 on: April 27, 2013, 11:47:28 PM »
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G*,
Sometimes color variation is more important than hue fidelity.
man from mars technique
Also, it's easy to go into lab mode from an rgb document by creating a stamp of all layers (shift-ctrl-alt-e) and converting the layer into a smart object. Double click on the smart object and convert to lab mode.
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BartvanderWolf
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« Reply #29 on: April 28, 2013, 05:39:11 AM »
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Sometimes color variation is more important than hue fidelity.

Hi,

As Dan says in the video; "there's no accounting for taste in these matters". And that's also coming from the man who says that 16-bit/channel editing is not necessary, which then comes as no surprise.

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Also, it's easy to go into lab mode from an rgb document [...]


Which already loses some of the color precision, and that's even before the inevitable conversion back to RGB colorspace. Why go there? What's it supposed to solve? Why not address the issue one might have with an image directly, and predictably?

I think in general it is bad idea to promote a technique that works out differently on each picture (it becomes a gimmick), and it prohibits learning to get true control over the specific things one wants to control.

Cheers,
Bart
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Jack Hogan
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« Reply #30 on: April 28, 2013, 09:45:43 AM »
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Starting from Raw, when you know your final image needs to be in sRGB, does it make more sense to

1) open it and perform PP in a much larger color space like ProPhotoRGB, converting to sRGB at the very end; or
2) open the Raw file directly in sRGB and stay in it throughout?

A few years ago I used to use Melissa D65 as my primary working color space, fine tuning images in that large space and only converting to sRGB at the end of the worlflow if needed.  Often in these cases the sRGB version required additional fine tuning but at least the original with all my adjustments would be in Melissa D65 for archival purposes and I wouldn't have to revisit it in the future if/when monitors/media improved.  Or so went the theory.

It worked well, except when I realized that I was spending a lot of time re-fine tuning most of my keepers because the vast majority of them needed to be turned into sRGB after all.  Statistics to the rescue: 90+% of my keepers need to be in sRGB because someone wants a copy via email or because someone wants to make a wallmart print today - only 1 or so a month get the special fine-art treatment, eventually being printed large to perfection.

And I started thinking that if red flowers clipped when going straight to sRGB, they probably still will when ending up in sRGB after ProPhoto: except that in the latter case you'd only realize that you are clipping them at the end of your session, adding additional PP time to get them the way you want them.  So I now do it the other way around: sRGB throughout for most keepers and only start in aRGB or a larger space with the very few images that I print large.  CNX2, which I use on 100% of my captures (90% of the time ending it there, without needing a trip to CS5),  makes it easy to make this change after the fact leaving all other adjustments intact.  This thread gave me the impulse to revisit this decision.

Thanks to Tim's Blue Ball, gollywop (on DPR)'s sunset and a flower Raw files, all of which have clipped histograms in sRGB that are not clipped in ProPhoto in the areas of interest, I used ACR 6.7 and CS5 to investigate the differences to be expected when (1) opening a Raw file in ProPhoto, applying adjustments and converting to sRGB at the end (perceptual, no black point compensation) vs opening the same file directly into sRGB and (2) sticking with it throughout.

If opened with the neutral camera profile and no adjustments are applied between opening and converting, the images resulting from the two workflows are virtually indistinguishable.  Here Tim's blue ball is shown with workflow 2, 1 and just ProPhoto :-) left to right on my calibrated/profiled Dell U2410 monitor run by Win7, which covers 95% of aRGB.


http://imgur.com/dRbwZKI

Very slight differences between the two workflows became apparent when adjustments were introduced.  Something as simple as changing the ACR 6.7 camera profile from Camera Neutral to Camera Landscape caused some slight but visible differences to appear in the two resulting images, neither necessarily better than the other.  Switching back to Camera Neutral and pushing a more aggressive adjustment (CEP3 Tonal Contrast at default settings) resulted in this comparison:


http://imgur.com/QgMIufn

There are tiny localized differences (sRGB only to the left, ProPhoto converted to sRGB to the right).  I know where they are, so I can spot them easily.  But neither image is clearly more accurate or preferable to the other in my view. 

So unless someone has a good argument for otherwise, I think I am going to stick with my current approach: sRGB as my day-to-day working color space, and aRGB/MelissaD65 for the few occasions when I feel it is necessary.  As opposed to the other way around.

Cheers,
Jack

PS For those who are wondering, ProPhoto/aRGB from start to finish give clearly better colors on my U2410 monitor than the sRGB/ProPhoto+sRGB workflows discussed above.  This is especially evident in gollywop's sunset image.
« Last Edit: April 28, 2013, 10:06:45 AM by Jack Hogan » Logged
Mark D Segal
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« Reply #31 on: April 28, 2013, 10:16:12 AM »
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Starting from Raw, when you know your final image needs to be in sRGB, does it make more sense to

1) open it and perform PP in a much larger color space like ProPhotoRGB, converting to sRGB at the very end; or
2) open the Raw file directly in sRGB and stay in it throughout?



Jack, today's inkjet printers and high-end displays occupy either just about all of or in certain hue areas more than ARGB(98), so to confine your gamut to sRGB is a serious technical and aesthetic limitation on the potential value of the images you produce.
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Mark D Segal (formerly MarkDS)
Author: "Scanning Workflows with SilverFast 8....." http://www.luminous-landscape.com/reviews/film/scanning_workflows_with_silverfast_8.shtml
digitaldog
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« Reply #32 on: April 28, 2013, 10:44:33 AM »
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Starting from Raw, when you know your final image needs to be in sRGB....

Just that bit alone is something to seriously consider! I can't imagine why you'd shoot raw only to then funnel that data into sRGB which pretty much has only one use (web or on-screen viewing using today's technology).

In the case of an Adobe raw workflow, you're working with high bit ProPhoto primaries, why not just stick with that as the master?
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Andrew Rodney
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Jack Hogan
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« Reply #33 on: April 28, 2013, 10:48:29 AM »
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Jack, today's inkjet printers and high-end displays occupy either just about all of or in certain hue areas more than ARGB(98), so to confine your gamut to sRGB is a serious technical and aesthetic limitation on the potential value of the images you produce.

Hi Mark,

Thanks for your comment but it answers a different question than mine, which is more practical in nature.  Why not choose the color space required by the vast majority of my images (>90%) - with no apparent IQ penalty - and use the wider color space only when needed (<10%), rather than the other way around?

Cheers,
Jack

PS I agree with you (and Andrew and others) that aRGB and ProPhoto are better overall.  But if you need to end up in sRGB...
« Last Edit: April 28, 2013, 10:50:12 AM by Jack Hogan » Logged
Mark D Segal
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« Reply #34 on: April 28, 2013, 10:57:22 AM »
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Jack, no, my response addresses exactly your question. Let me put it this way: if it is now the case, AND will forever after be the case, that the output devices you and others use for viewing photographs do not have gamut capacity exceeding sRGB, then sure, no one will ever see what can't be seen and working in sRGB would be just fine. But even now, that is manifestly not the case. We can easily see beyond sRGB. My NEC PA271W display and Epson 4900 both see WAY beyond sRGB. You only need to put up a wide gamut photo and dumb it down to sRGB to see the dilution of image quality before your very eyes. Modern technology has greatly by-passed sRGB and will continue evolving to ever expanded gamut capacity. By losing all that valuable information in every photo you process that has intrinsic gamut beyond sRGB, you are sacrificing a lot for no reason.
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Mark D Segal (formerly MarkDS)
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Jack Hogan
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« Reply #35 on: April 28, 2013, 11:10:32 AM »
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Just that bit alone is something to seriously consider!

I hear you, Munsell is stirring in his grave Smiley

I can't imagine why you'd shoot raw only to then funnel that data into sRGB which pretty much has only one use (web or on-screen viewing using today's technology).

Is that right?  I was under the impression that if you didn't print your own most labs still want sRGB these days.

In the case of an Adobe raw workflow, you're working with high bit ProPhoto primaries, why not just stick with that as the master?

That makes sense, if the end point is not sRGB.  But what if it is?
« Last Edit: April 28, 2013, 11:27:41 AM by Jack Hogan » Logged
Mark D Segal
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« Reply #36 on: April 28, 2013, 11:17:17 AM »
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What I'm suggesting to you is that your "end-point" SHOULD NOT be sRGB, for solid technical and aesthetic reasons.
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Mark D Segal (formerly MarkDS)
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Jack Hogan
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« Reply #37 on: April 28, 2013, 11:25:37 AM »
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Jack, no, my response addresses exactly your question. Let me put it this way: if it is now the case, AND will forever after be the case, that the output devices you and others use for viewing photographs do not have gamut capacity exceeding sRGB, then sure, no one will ever see what can't be seen and working in sRGB would be just fine. But even now, that is manifestly not the case. We can easily see beyond sRGB. My NEC PA271W display and Epson 4900 both see WAY beyond sRGB. You only need to put up a wide gamut photo and dumb it down to sRGB to see the dilution of image quality before your very eyes. Modern technology has greatly by-passed sRGB and will continue evolving to ever expanded gamut capacity. By losing all that valuable information in every photo you process that has intrinsic gamut beyond sRGB, you are sacrificing a lot for no reason.

I understand the archival value of working in a larger (although not necessarily the largest) color space, but that's not what the question is about.  Keep in mind that I am an amateur photographer with the objective to print one fine (to me Smiley print a month or so - not every day.

Capture NX2 allows you to reopen an old file, even after extensive global and local editing, and change the original color space in a couple of clicks.  It reloads the original Raw data in the new working color space and re-applies each and every single adjustment step in the original sequence in a matter of a seconds.  Then I check the histogram and make sure that nothing desirable is clipped.  If it is I try to fix it.

If I start in sRGB I need to do this re-opening in less than 10% of the files.  If I start in ProPhoto, I need to do it for 90% of the files.  There is no question that the image looks a little better in ProPhoto/aRGB on my monitor.   But which is better from a practical standpoint for my uses?

« Last Edit: April 28, 2013, 11:36:40 AM by Jack Hogan » Logged
Jack Hogan
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« Reply #38 on: April 28, 2013, 11:35:14 AM »
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What I'm suggesting to you is that your "end-point" SHOULD NOT be sRGB, for solid technical and aesthetic reasons.

Ok, what should it be then?
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Mark D Segal
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« Reply #39 on: April 28, 2013, 11:36:05 AM »
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OK Jack - I hear you - from a purely personal/practical standpoint it depends on what output devices you use and will use, what you see, whether you care about what you don't see and what you are happy with.
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Mark D Segal (formerly MarkDS)
Author: "Scanning Workflows with SilverFast 8....." http://www.luminous-landscape.com/reviews/film/scanning_workflows_with_silverfast_8.shtml
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