Author Topic: Correct 32bit workflow between Corona and Photoshop (ArionFX)  (Read 13949 times)

2015-11-04, 14:53:21

ikercito

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Hi guys!

I'm very happy with the new 1.3 update, it solved quite a few minor complains I had.

Anyway, my question goes along other lines... I'm trying to find the correct 32bit workflow from Corona to Photoshop (I use ArionFX to open the EXRs)

The way I do it, I see major colour shifts from Corona VFB to Photoshop. This is my workflow:

I export in 32bit Full Float, and open them in Ps, there's usually a colour shift and darkening in the shadows compared to Corona VFB. I have "Proof Colours - CMYK" activated to avoid even a greater shift/darkening. My first step is to tonemap the render with ArionFX, and in the preview window of the plugin the result gets a little better (better gamma/exposure/shadows but still colour shifts in the shadows with default values). Back from the plugin, the result changes again to deeper shadows and the colour shift is more notable. Seems to me like it's all a problem of how PS shows the 32bits...(?)

Once I convert my image to 16 bit (Exposure and Gamma, default values), the general shadow/highlight ratio is mantained but the colour tint in the shadows(usually towards green) is even made more present.

Does anyone have any tips to avoid all these colour fluctuations in PS...? Is there anything wrong with the workflow?

Thanks in advance for your help guys.

(I'll try to supply a few images to document all this mess shortly)

2015-11-04, 15:08:54
Reply #1

Juraj

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There shouldn't be any (too noticeable) shift between Photoshop and Corona's framebuffer under correct color pipeline. (edited slightly)

3dsMax isn't color managed application, so unless you're using VFB+ with 3D LUT file, you're seeing your general color profile.

Open your Photoshop preferences/Color settings and set it to "Ask when opening". This way Photoshop will not do any automatic conversion without you asking and specifying what to do.
Also set your general Working space to the one your Monitor is actually capable of working with. I.e, if you don't have Wide-gamut display, don't select AdobeRGB but sRGB. Then everything will look identical across applications. Don't select your monitor profile or other stupid stuff in case you have software calibrated it with.

You don't need to use any proof setup in production. It's not intended for that. It should be used occasionally as preview for your intended output, CMYK only for printing. Since the conversion between sRGB to CMYK is one relative colorimetric you shouldn't be seeing any difference anyway.


But to look into this further (because it's not necessarily color management issue). Are you saving as linear .exr file but using contrast setting in Corona ?
« Last Edit: 2015-11-04, 17:04:45 by Juraj_Talcik »
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2015-11-04, 15:52:30
Reply #2

atelieryork

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There shouldn't be any shift between Photoshop and Corona's framebuffer.

3dsMax isn't color managed application, so unless you're using VFB+ with 3D LUT file, you're seeing your general color profile.

Open your Photoshop preferences/Color settings and set it to "Ask when opening". This way Photoshop will not do any automatic conversion without you asking and specifying what to do.
Also set your general Working space to the one your Monitor is actually capable of working with. I.e, if you don't have Wide-gamut display, don't select AdobeRGB but sRGB. Then everything will look identical across applications. Don't select your monitor profile or other stupid stuff in case you have software calibrated it with.

You don't need to use any proof setup in production. It's not intended for that. It should be used occasionally as preview for your intended output, CMYK only for printing. Since the conversion between sRGB to CMYK is one relative colorimetric you shouldn't be seeing any difference anyway.


But to look into this further (because it's not necessarily color management issue). Are you saving as linear .exr file but using contrast setting in Corona ?

Juraj,

If you calibrate your monitor (with i1 for example), should you use the generated profile as your working colour profile in Photoshop? I've been doing this and obtained what seems like the best results. Is is best to use AdobeRGB? I have a wide-gamut U3011.

Cheers,
Alex York
Atelier York
www.atelieryork.co.uk
max 2016 sp1, corona 1.3 final, win 8.1. pro

2015-11-04, 16:24:37
Reply #3

ikercito

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Hi Juraj! Thanks a lot for helping out...! :)

First of all, EXR is saved with the default values, so no contrast applied. No VFB+ either.

Second, PS Color Settings were set to "Preserve" but now I changed it to "Ask". But  I'm getting a prompt about, EXR being a file format that doesn't support color profiles, so it asks to Assign a profile (sRGB or other..) everytime I open it. I'm opening a JPG straight from the VFB to compare, and either way, the color shifts a lot...!

My monitors are not a great deal, Asus IPS models, but both are calibrated with a Spyder3 and Dispcalgui software (although I sometimes don't trust this combo..). It's all set to work in sRGB.

Here's a comparison of the EXR just opened in PS (took a screenshot, not to mess with any further conversions) and the same image in JPG saved straight from Corona VFB. Both should be the same right?!?! Check out shadows and tint under the table/carpet and color saturation in the brick wall....

Thanks for taking your time! ;)

***BTW Atelieryork... I think that's a very bad choice! But I might be wrong, thought I had color profiles and this stuffed worked out, but seems like I'm more messed up than ever right now... :D

2015-11-04, 16:26:13
Reply #4

ikercito

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And forgot to say "Proof Colors" has been deactivated now... :)

2015-11-04, 16:46:41
Reply #5

maru

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Note: this is not something like a "recommended setup"! It is just here to present some facts. The main topic of the original conversation was "why am I getting different colors/brightness in PS compared to Corona VFB?".

We've recently had a similar report at support. Here are some notes which may be helpful (or confusing, that's what usually happens if you go _deeper_ into color profile things):

Quote
the tiny differences (especially in blacks) are caused by difference between gamma 2.2 and "true sRGB gamma", which cannot be expressed with a single number such as 2.2

Quote
Right click on desktop>screen resolution
 
·         Then advance settings
 
·         Then colour management tab
 
·         Then colour management
 
·         Select your graphics card – display 1
 
·         Tick “ use my settings for this device” on
 
·         Remove the ICC profile that is on there – mine was a DELL MONITOR ONE. GET RID
 
·         CLICK ADD
 
·         Srgb iec61966-2.1

After the 2nd solution you should be getting 99,99% the same result in Corona VFB and in Photoshop when opening the EXR.
« Last Edit: 2015-11-04, 17:30:48 by maru »
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2015-11-04, 16:51:26
Reply #6

atelieryork

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We've recently had a similar report at support. Here are some notes which may be helpful (or confusing, that's what usually happens if you go _deeper_ into color profile things):

Quote
the tiny differences (especially in blacks) are caused by difference between gamma 2.2 and "true sRGB gamma", which cannot be expressed with a single number such as 2.2

Quote
Right click on desktop>screen resolution
 
·         Then advance settings
 
·         Then colour management tab
 
·         Then colour management
 
·         Select your graphics card – display 1
 
·         Tick “ use my settings for this device” on
 
·         Remove the ICC profile that is on there – mine was a DELL MONITOR ONE. GET RID
 
·         CLICK ADD
 
·         Srgb iec61966-2.1

After the 2nd solution you should be getting 99,99% the same result in Corona VFB and in Photoshop when opening the EXR.

Should this advice be followed if you have properly calibrated your monitor with i1/spyder etc? I imagine that the default monitor profiles are rubbish, but if you calibrate then shouldn't we be using the actual calibration profile? I mean, that is required for the calibration to work in the first place. Then it's a question of whether or not to use the calibrated profile in PS or to use srgb...
Alex York
Atelier York
www.atelieryork.co.uk
max 2016 sp1, corona 1.3 final, win 8.1. pro

2015-11-04, 16:52:52
Reply #7

Juraj

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By using monitor ICC profile as working space in Photoshop you're still clamping the spectrum (U3011 has only 96perc. of AdobeRGB), and if you (I presume you do, because storing images with monitor profile is useless for everyone except for you) convert to output profile in the end, for example for printing (most printing companies prefer AdobeRGB/ProPhoto to do their own calibrations instead of CMYK) you're effectively converting from smaller space to larger space. And doing redundant and needless conversions.

The calibrated ICC profile belongs to display color management on GPU level (if you want to maintain fully managed workflow other than full sRGB), with exception of newer panels (like U3014) which can store 3D LUT inside OSD (hardware calibration is the only way to keep consistent ICC usage)

To check if your monitor is using your Display factory or calibrated profile type "Color Management" into Windows search box (should work from 7 to 10, but I am currently only on Windows10) and in the first tab should be listed 'profiles associated with this device'.
This is where the profile should go. Since I am using hardware calibrated profile stored in OSD, I have my default monitor 'u3014.icm' file installed.

The working space should therefore be decided depending on your output. I long time ago discarded AdobeRGB because such pipeline is incredibly hard to maintain. Windows fucks it, Mobile devices fuck it up, all the browsers except for Firefox (but not in default state) fuck it up, 99perc. of my clients use regular sRGB monitor like rest of the world, if, for example they have "high end", it's AppleCinema and those like, which is again just regular sRGB display. For images that go to print, I am not too bothered by clamping my spectrum since I am not the one doing the proof setup anyway so I am not phased about loosing slight fidelity in red/greens. I don't see literally any benefit to use it therefore at the moment.
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2015-11-04, 16:56:14
Reply #8

Juraj

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Should this advice be followed if you have properly calibrated your monitor with i1/spyder etc? I imagine that the default monitor profiles are rubbish, but if you calibrate then shouldn't we be using the actual calibration profile? I mean, that is required for the calibration to work in the first place. Then it's a question of whether or not to use the calibrated profile in PS or to use srgb...

Depends. Imho it shouldn't, the monitor should use the profile that is associated with it, in case of calibration, the calibrated one. Of course, in case of sRGB only capable displays, it hardly matters much. But this isn't the case for wide-gamut panels.
So no, keep your display profile there.

Photoshop working space on other hand, should use device-independent profile associated with your output intentions. Web ---> Adobe sRGB. Or in case of wide-gamut pipeline, AdobeRGB(or ProPhoto,etc.. what suits you) and then convert down to smaller space for web use, and keep larger space for print proofing.
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2015-11-04, 17:09:47
Reply #9

Juraj

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the tiny differences (especially in blacks) are caused by difference between gamma 2.2 and "true sRGB gamma", which cannot be expressed with a single number such as 2.2

This is a very slight difference, and shouldn't be discernible to point where it can be described as "heavy shifts". But it's also a reason why Vray for example uses "sRGB" for proofing the colors of linear file in frame-buffer :- ).


I will correct myself slightly on the shifts between 3dsMax and Photoshop that you can't be avoided. 3dsMax isn't color managed application, so unless you're using lut profiles in framebuffer (for example in Vray's framebuffer or VFB+ on Corona), it will shift depending on how clamped your working space is compared to display profile. Setting both of this to same should create consistency, but I would again suggest for this to be device-independent profile and not your display one. Doing this is, again imho, redundant on non-wide gamut displays.

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2015-11-04, 17:31:58
Reply #10

atelieryork

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Roger that, thank you!

So, essentially - monitor calibration colour profile in windows colour settings, then SRGB in photoshop. That's what I've been using for years and it seems to have worked fine, but worth checking.
Alex York
Atelier York
www.atelieryork.co.uk
max 2016 sp1, corona 1.3 final, win 8.1. pro

2015-11-04, 17:58:53
Reply #11

ikercito

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We've recently had a similar report at support. Here are some notes which may be helpful (or confusing, that's what usually happens if you go _deeper_ into color profile things):

Quote
the tiny differences (especially in blacks) are caused by difference between gamma 2.2 and "true sRGB gamma", which cannot be expressed with a single number such as 2.2

Quote
Right click on desktop>screen resolution
 
·         Then advance settings
 
·         Then colour management tab
 
·         Then colour management
 
·         Select your graphics card – display 1
 
·         Tick “ use my settings for this device” on
 
·         Remove the ICC profile that is on there – mine was a DELL MONITOR ONE. GET RID
 
·         CLICK ADD
 
·         Srgb iec61966-2.1

After the 2nd solution you should be getting 99,99% the same result in Corona VFB and in Photoshop when opening the EXR.

Should this advice be followed if you have properly calibrated your monitor with i1/spyder etc? I imagine that the default monitor profiles are rubbish, but if you calibrate then shouldn't we be using the actual calibration profile? I mean, that is required for the calibration to work in the first place. Then it's a question of whether or not to use the calibrated profile in PS or to use srgb...

Just checked this and you're right Maru. At least color wise there are no shifts right now.. There's is however a slight change in luminosity in some areas, probably related to how PS displays the whole 32bit spectrum (I guess).  That doesn't really bother me, as it mainly focuses on the highlight areas and I'll be dealing with that with ArionFX tonemapping.

So, seems like the muddy green shadow areas are gone now, and the starting problem is solved. But....

Does this mean I'm using a wrong setup now? I've just ditched the profile from the calibration and I'm using a standarized one... Can I trust the color accuracy of my monitor now? Am I causing more trouble by doing the above than I was before?

This is terribly confusing... I should have paid more attention to the color management 101 subject in university...! (ages ago) :(
« Last Edit: 2015-11-04, 18:20:39 by ikercito »

2015-11-04, 19:45:24
Reply #12

Juraj

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I should have paid more attention to the color management 101 subject in university...! (ages ago) :(

:- D Thumbs up.

But to answer you, yes, you now have 'consistency' between applications (because everything is sRGB), but you have forfeited any option for calibration outside of OSD, which, with exception of displays that have hardware calibration (can store LUT profiles in OSD), you can only tweak individual color channels.
So if your display isn't calibrated, you're essentially looking at wrong representation.

The correct way would be to use your calibrated profile in GPU (unless you have display that has hardware calibration option), and use generalized color profile as workspace. If you see wild discrepancy this way then, than you calibrated it wrongly, or you calibrated outside of your workspace gamut.

If you want to discard human error on your side, I suggest downloading calibrated ICC from TFT Central. While it wasn't calibrated using your exact unit, it will be within range of what is correct in case your own calibration is completely outside.

Roger that, thank you!

So, essentially - monitor calibration colour profile in windows colour settings, then SRGB in photoshop. That's what I've been using for years and it seems to have worked fine, but worth checking.

Indeed. You can choose both sRGB and AdobeRGB if you're not clamping in OSD (there is factory profile for sRGB which you can't further tweak, but can still calibrate software wise and use that lut in Display in GPU).
If you maintain full gamut in your display (by using factory profile for AdobeRGB in OSD and then software calibrating that in desktop), it's preferable for you to maintain AdobeRGB workspace as well, and then convert to sRGB when outputing to web.
« Last Edit: 2015-11-04, 20:09:46 by Juraj_Talcik »
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2015-11-05, 10:09:38
Reply #13

atelieryork

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Thanks Juraj.

I'm going to summarise to keep it simple, so I can be sure what I'm doing is correct, and for the benefit of others:

1) reset monitor to default settings and then set it to SRGB mode, if available
2) calibrate monitor using spyder/i1 etc and load the profile into windows color settings (done automatically when you save the profile)
3) set photoshop working color space to SRGB

At this point the full workflow from render to photoshop to monitor to web should be SRGB and consistent, I believe. You then convert to CMYK if needed for printing (these days I leave that to the printing company when necessary - results have been fine). This is what I've been doing for some years, so I hope this looks correct!
Alex York
Atelier York
www.atelieryork.co.uk
max 2016 sp1, corona 1.3 final, win 8.1. pro

2015-11-05, 12:26:28
Reply #14

ikercito

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Thanks a lot Juraj, it all kind of makes a bit more sense now :)

Just to make sure I got it right...

The correct way would be to use your calibrated profile in GPU (unless you have display that has hardware calibration option), and use generalized color profile as workspace. If you see wild discrepancy this way then, than you calibrated it wrongly, or you calibrated outside of your workspace gamut.

The generic sRGB profile should go in windows color management as a standard color space, and the calibrated profile should go into my GPU settings? Can't seem to find any option in Nvidia software for this.. And definitely my monitors do not allow for hardware calibration (They're cheapo Asus VX239). So for now the calibrated profile is not being used.

The way I understood it... Now I have consistency between applications, cause they're all set to sRGB. There are no discrepancies between PS and Max now, but the output from the display is uncalibrated. Seems like the calibration was not properly done, cause that profile is the one giving me the headaches... (I shouldn't trust that second hand Spyder3 too much, never been too reliable)

Couldn't find any profiles at TFTcentral for my specific model, but the NEC P232 uses the same panel so I might give a try to those profiles... I'll report back with the results.

Thanks a lot again!