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Author Topic: DCamProf - a new camera profiling tool  (Read 719907 times)

Rado

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Re: DCamProf - a new camera profiling tool
« Reply #1400 on: January 07, 2017, 11:06:37 am »

Apologies if this was discussed already but would making my own profiles allow me to match two cameras in regard to colors?
I use a Canon 6D and 7D2 in Capture One and the colors from each don't look quite the same. I see that it's possible to make C1 camera profiles now so I wonder if it's worth trying out.
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scyth

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Re: DCamProf - a new camera profiling tool
« Reply #1401 on: January 07, 2017, 02:25:20 pm »

Apologies if this was discussed already but would making my own profiles allow me to match two cameras in regard to colors?
I use a Canon 6D and 7D2 in Capture One and the colors from each don't look quite the same. I see that it's possible to make C1 camera profiles now so I wonder if it's worth trying out.

in general a noticeable (for hoi polloi eyes) color difference is either because of sufficiently different CFA or sufficiently different profiles... in C1 you can select 7D2 profiles for 6D raws and vice versa... if colors are way different after you try that then naturally the reason is quite different CFAs... then to try to come up with the more or less the same color (for your eyes) from them you really need LUT profiles and then from practical stand point you want either a real target with many patches (which I bet you don't have) or deal with synthetic targets... granted you can always live with whatever results you receive, they still might be a better match than canned profiles from C1 for your subjective taste - may be you really only need to match greens ? or reds ? or blues and only approximately... may be C1 color editor will be the better option then
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torger

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Re: DCamProf - a new camera profiling tool
« Reply #1402 on: January 12, 2017, 06:04:06 am »

Apologies if this was discussed already but would making my own profiles allow me to match two cameras in regard to colors?
I use a Canon 6D and 7D2 in Capture One and the colors from each don't look quite the same. I see that it's possible to make C1 camera profiles now so I wonder if it's worth trying out.

Yes two cameras should look quite close indeed if you make two profiles from identical targets in identical lighting situations. I doubt that the color filters differ that much between 6D and 7D2, the most probably differ some, but the main design principles are probably the same as it's both fairly recent Canon cameras.

That they do not look the same in in C1 could be that Phase One have had different design goals for the profiles. It's quite common that raw converter makers make cameras look more different than they need to be. I don't really know why, if it's just a side-effect of their workflow, or if they have some marketing reason to differentiate cameras. Sure their medium format looks are unique for an obvious reason, but I don't see why one would want to differentiate two Canon cameras.

Even if the SSFs (ie color filters) are quite drastically different cameras should still look very much alike, at least in normal light conditions for normal color saturations. Most modern cameras can match a target like a CC24 quite accurately with just a matrix (that was not the case for say 10-15 years ago) so a LUT on top doesn't need to make much stretching job to make them match. One of the key arguments why I am myself always using my own profiles is because I want my cameras, even from different manufacturers, to produce the same color and a neutral color. Simply so I get a well-defined starting point in my regular post-processing.

If you make profiles for the cameras and do quick A/B swaps on the same colorful shot you will still quite easily detect some differences, especially in how light colors are rendered, but hue and saturation should match well, which means that if you see the images a bit apart they will be very hard to differ.
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torger

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Re: DCamProf - a new camera profiling tool
« Reply #1403 on: January 17, 2017, 07:44:58 am »

I just made a hotfix 1.0.5 release as I became aware that the exclude patch and glare parameters for the make-profile command hasn't had any effect since 1.0.1. Probably not many as me have noticed earlier since if you use a split workflow with make-target command as I describe in the tutorial you're not affected.

There will be a bit larger update later on, but I'm only doing critical fixes now on DCamProf until the commercial "Lumariver Profile Designer" is out. Talking about that there will be some more time until I can release that as I've expanded the feature set to include ICC profiling and more, so I'm currently guessing it will slip out of Q1 into early Q2, very much dependent on pressure from other simultaneous projects.
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Bart_van_der_Wolf

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Re: DCamProf - a new camera profiling tool
« Reply #1404 on: January 17, 2017, 11:26:56 am »

I just made a hotfix 1.0.5 release as I became aware that the exclude patch and glare parameters for the make-profile command hasn't had any effect since 1.0.1. Probably not many as me have noticed earlier since if you use a split workflow with make-target command as I describe in the tutorial you're not affected.

There will be a bit larger update later on, but I'm only doing critical fixes now on DCamProf until the commercial "Lumariver Profile Designer" is out. Talking about that there will be some more time until I can release that as I've expanded the feature set to include ICC profiling and more, so I'm currently guessing it will slip out of Q1 into early Q2, very much dependent on pressure from other simultaneous projects.

Hi Anders,

As a Capture One user, now you've got my attention ...  ;)

Cheers,
Bart
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== If you do what you did, you'll get what you got. ==

torger

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Re: DCamProf - a new camera profiling tool
« Reply #1405 on: January 18, 2017, 03:35:56 am »

As a Capture One user, now you've got my attention ...  ;)

Yep there will be C1 support, which is the most hellish of all of course ;-), due to their own idea of how an ICC profile should be applied. There's no less than three curves involved. There's their close-to-but-not-quite 1.8 encoding gamma, their user-selectable in-software curve, with or without white-level adjustments, and a small modifier curve embedded into the ICC profile's Lab LUT. It was hard to not bloat the GUI just to support C1's own idea of ICC pipeline (there are other ICC-using converters too, don't want it to make a C1-specific software), but I think it came out quite okay.

The software will still for sure require a manual though, as it won't be self-evident unless you know a little about how the pipeline works. The DNG workflow will be a bit more straightforward, but it also have its own quirks -- that DNG LUTs can't scale the neutral axis may lead to some confusion and I'll try to minimize that if I can. The nice thing with ICC is that it's really a plain LUT, 3 values in 3 values out, no fuzz, while DNG LUTs have their special constraints that means that there's some things you can't do.

I'm currently looking into including a 3D correction LUT for reproduction and scanner use cases, and DNG is giving me a headache there as you can't correct the neutral axis. By skipping the HSM lut and putting it all into the looktable I can use the tonecurve to at least linearize the neutrals, which probably will be the way to go for the reproduction/scanner use case for DNG profile users. Not sure I will include a 3D LUT for the first release though. The main focus is still general-purpose profiles and there 3D correction LUTs doesn't make sense as the exposure is variable, then the current 2.5D is the way to go.
« Last Edit: January 18, 2017, 03:45:31 am by torger »
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Hening Bettermann

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Re: DCamProf - a new camera profiling tool
« Reply #1406 on: January 20, 2017, 02:20:37 pm »

Hi!
I have successfully built ICC profiles with DCamProf. Now I wanted to try the combo profile based on the Imaging Resource target of a CC24 and a CCSG. But while
./dcamprof-v0.10.4 make-profile -n HB_a7r2_CC24 -g -i D50 -B -S ImaRes_CC24.ti3 HB_a7r2_CC24.json
results in the .json profile,
./dcamprof-v0.10.4 make-profile -n HB_a7r2_combo -g -i D50 -B -S combo.ti3 HB_a7r2_combo.json
only displays the manpage. What am I missing? (The .ti3 is successfully created).
Thank you for your help - Hening.

scyth

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Re: DCamProf - a new camera profiling tool
« Reply #1407 on: January 20, 2017, 04:55:00 pm »

Hi!
I have successfully built ICC profiles with DCamProf. Now I wanted to try the combo profile based on the Imaging Resource target of a CC24 and a CCSG. But while
./dcamprof-v0.10.4 make-profile -n HB_a7r2_CC24 -g -i D50 -B -S ImaRes_CC24.ti3 HB_a7r2_CC24.json
results in the .json profile,
./dcamprof-v0.10.4 make-profile -n HB_a7r2_combo -g -i D50 -B -S combo.ti3 HB_a7r2_combo.json
only displays the manpage. What am I missing? (The .ti3 is successfully created).
Thank you for your help - Hening.

why the old version and then post the .ti3 file just in case
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Hening Bettermann

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Re: DCamProf - a new camera profiling tool
« Reply #1408 on: January 20, 2017, 05:32:57 pm »

Hi scyth,
why the old version? Well it worked last year, and I have so far seen no need to update. Anyway, here is the .ti3 file if you care to have a look at it.

scyth

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Re: DCamProf - a new camera profiling tool
« Reply #1409 on: January 20, 2017, 10:51:41 pm »

Hi scyth,
why the old version? Well it worked last year, and I have so far seen no need to update. Anyway, here is the .ti3 file if you care to have a look at it.

you are using -g for make-profile :

-g <target-layout.json> provide target layout for glare matching and/or flatfield correction.

where is the json file for it ?

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torger

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Re: DCamProf - a new camera profiling tool
« Reply #1410 on: January 21, 2017, 03:13:29 am »

Hi!
I have successfully built ICC profiles with DCamProf. Now I wanted to try the combo profile based on the Imaging Resource target of a CC24 and a CCSG. But while
./dcamprof-v0.10.4 make-profile -n HB_a7r2_CC24 -g -i D50 -B -S ImaRes_CC24.ti3 HB_a7r2_CC24.json
results in the .json profile,
./dcamprof-v0.10.4 make-profile -n HB_a7r2_combo -g -i D50 -B -S combo.ti3 HB_a7r2_combo.json
only displays the manpage. What am I missing? (The .ti3 is successfully created).
Thank you for your help - Hening.

There should be a layout description file after the -g parameter, unless it was different back at that version, I don't remember. You can skip the parameter though, for the combo target it won't work anyway. I'd recommend to get the latest version, I have binaries directly on the web nowadays. It's easier to provide help if you use the latest version as I quickly forget what was different with the older ones :-).

When it shows the manpage, if you scroll all the way back to the top you usually get an error message of what went wrong. I should probably split the manpage per command as it's becoming veeeery long so noone sees the error message at the top...
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Hening Bettermann

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Re: DCamProf - a new camera profiling tool
« Reply #1411 on: January 21, 2017, 01:18:21 pm »

Many thanks to the both of you! I have now downloaded version 1.0.4, and I see there are new things I have to study before I go on.
Good light! - Hening

Hening Bettermann

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Re: DCamProf - a new camera profiling tool
« Reply #1412 on: January 24, 2017, 05:33:43 pm »

Hi again!

I have now done a little reading and have a few questions:

1-In the section 'DCamProf's neutral tone reproduction operator', you (Anders) write:
'However, most raw converters are designed for profiles that have a fixed curve applied.'
How does RawTherapee do in this regard?

In the command reference to make-profile:
2- -p, -f, -e, -m, pre-generated matrices if you want to skip the matrix finder steps.

I don't understand this. What are the matrix finder steps, and what are these flags?

3-
-t <linear | none | acr | custom.json>, embed a tone-curve in the output DCP or ICC, and apply the default tone reproduction operator.

What is the difference between 'linear' and 'none'?  I assume/hope, that one of them means 'Apply the neutral tone reprodution operator, but no other curve'; and that the other means 'keep the profile entirely linear'. But which is which? (I want to try both).

Thank you for your help!

torger

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Re: DCamProf - a new camera profiling tool
« Reply #1413 on: January 25, 2017, 07:57:26 am »

RawTherapee has the "perceptual tone curve" which is a simplified realtime version of DCamProf's neutral tone operator, so using that you could provide a profile with only colorimetric correction and no curve (linear curve). Most new bundled RawTherapee profiles are generated with DCamProf and have a curve embedded though.

The pre-generated matrices flags can be used if you want to render matrices in one run and the LUT in another. This is not a common workflow, and there are generally two reasons for it. 1) You're testing lots of LUT tuning flags over and over again in serveral runs and don't want to wait for matrix optimizer for each run, 2) you're using different target for the matrix and the LUT, usually a smaller target for the matrix. The rationale being that super-saturated colors found in larger targets may be interesting to correct with the LUT, but is more disturbance than gain when it comes to the linear matrix optimization -- cameras are designed to linearly match "normal range" colors well, so it's better to use normal range colors when making the the matrix. That said the matrix optimizer usually comes to about the same conclusion also when using the larger target. So for me it's most often the first reason, to save time when tuning LUT parameters.

Oh, if you haven't the difference between matrix and LUT -- matrix is the base 100% linear correction with 100% perfect gradients. On top of that you can make non-linear corrections to better match colors using the LUT, short for Lookup Table. DCamProf's native LUT is not a traditional LUT but a mathematical model with anchors, which is sampled into a traditional LUT when you make an ICC or a DCP.

The difference between "linear" and "none" is only applicable to DCP (in the ICC docs it should say only "none"). The resulting matrix/LUT will be the same with linear and none, that is adapted for no curve (linear curve), but if "none" is chosen the curve element is left out from the DCP, otherwise a linear curve is put there. When the DCP lacks a curve raw converters have different ways of handling it. ACR/Lightroom will apply the standard ACR curve, while others may treat it as a linear curve. Thus I recommend to provide "linear" so it's clearly defined what you want.
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Hening Bettermann

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Re: DCamProf - a new camera profiling tool
« Reply #1414 on: January 25, 2017, 01:16:54 pm »

Hi Anders,
thank you for your fast reply.
Sorry I have to ask some follow-up questions.

1-Concerning your first paragraph:
Does this mean, if I convert with RT using a linear matrix or LUT profile, RT will under the table use a simplified version of your ntro?
 (I'm aware of that a LUT profile by definition can not be strictly linear; but 'with no tone curve')
(How) can I achieve that RT doesn't add anything on it's own? I mean: that it puts out a linear TIF, if I choose 'linear'; and a TIF with your ntro (full version) but no other curve, if I choose that?

2-Concerning the last paragraph in your answer:
Now I understand the difference between 'none' and 'linear'; but I still don't understand what I have to enter if I want 'the ntro, but no other curve'. (The command reference says 'Embed a tone curve [...] AND apply the default tone reproduction operator'.)
Or is it like this:
-t linear : will embed ntro, but no other curve.
no -t flag in the command: no ntro, no other curve.
?

BTW I use neither ACR nor Lightroom. I have hitherto used Iridient, but want to move to RT now. 

And a new question:
3-
"-I <target XYZ reference values illuminant>, can be specified in the same way as the calibration illuminant (-i). If spectral information is provided in the target the XYZ values will be re-generated according to chosen illuminant (and observer) when possible, and then this parameter is thus ignored. If there is no spectral information itís however important that the illuminant and observer matches what was used for the target."

I read this as "the illuminant, for which the XYZ reference values for the target were calculated".
Which is that? How can I know? maybe D50, but I want to be sure.

The ImaRes target for the Sony a7r2 was obviously shot with flash. So for the -i flag, I think I have to enter exif tag 4.
I want to make ICC and single-illuminant dcp profiles.
What should I enter for the -I flag?

scyth

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Re: DCamProf - a new camera profiling tool
« Reply #1415 on: January 25, 2017, 06:50:12 pm »

I have hitherto used Iridient

AFAIK iridient can use both "icc/icm" and "dcp" profiles
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Hening Bettermann

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Re: DCamProf - a new camera profiling tool
« Reply #1416 on: January 25, 2017, 07:20:12 pm »

Yes it can. This is not the reason that I want to change.
Good light!

torger

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Re: DCamProf - a new camera profiling tool
« Reply #1417 on: January 26, 2017, 03:12:58 am »

1) RT doesn't add anything automatically, but like all raw converters it allows you to add contrast via a curve, but unlike most raw converters you can choose which tone operator to use, "Standard = RGB", "Film-like = ACR", "Perceptual = similar to DCamProf", and a couple of more. With RT you can choose which elements of the DCP to activate, for example you may skip activating the looktable and curve, which for a typical DCamProf profile would leave only the colorimetric aspect. Anyway you don't need to worry, per default RT behaves as you would expect, it's just that you have so much more control, a bit too much control to be that software that everyone wants to use, but it's nice when you're a control freak ;)

2) Uhmm... there's been some changes back and forth on when the NTRO gets activated or not, and I'm really focused on the GUI version so I'm not really sure without testing what happens with a particular parameter combination in the latest version. What should happen though is that as soon as you have a parameter that requires the NTRO to be activated it will. For example if you have linear curve and no gamut compression there will be no NTRO as it would make no difference. If you activate gamut compression, the NTRO will be activate even if you have linear curve as it depends on that, but really the basis of using a tone reproduction operator is that there is a curve other than linear. If you use a linear curve I've assumed that the user is making a profile for reproduction, and then you just want a colorimetric profile.

I'm not too familiar with Iridient so I don't know what it does if the profile lacks an embedded curve, but it would be easy to find out by testing, or just ask Brian.

3) The best is if your target reference file contains spectra, then XYZ values can be recalculated from scratch for any illuminant you choose. If you measure your own targets with a spectrometer you should be able to make one with spectra. If you're using a file provided with DCamProf they all have spectra. If you've got the reference file from the manufacturer it's likely not containing any spectra, and then you need to know what illuminant that was used when the XYZ values in the file was calculated. It's nearly always D50 or D65 with 2 degree 1931 standard observer. Unfortunately there is no standard field to provide information of which illuminant that was actually used, but often it's stated in the description field or some non-standard field, so look at the text file and search for D50 or D65 and see what you find. For example you can find something like this:
[DESCRIPTOR "L* a* b* Batch average data (light D50, viewing angle 2)"] and then you see that D50 with the standard 2 degree 1931 observer has been used.

Exif tag 4? What's that? Flash can generally be approximated to D50. An exact match is not really that important. When the calibration illuminant is said to be different from D50 there will be chromatic adaptation transform applied, the reason to simulate the slight appearance differences of colors under different light, making reds a bit brighter for StdA for example. In theory the color temperature estimation of the DCP becomes better with an exact calibration illuminant, but that's only in theory, and for single illuminant profiles it has no effect, and if you use a raw converter like Lightroom that takes custom wb from the temperature estimate rather than storing the true RGB multipliers you'd probably want to embed the original ACR color matrices anyway. I don't know how Iridient developer does that aspect.
« Last Edit: January 26, 2017, 03:16:25 am by torger »
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Hening Bettermann

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Re: DCamProf - a new camera profiling tool
« Reply #1418 on: January 26, 2017, 02:46:17 pm »

Hi Anders

Thank you for your extensive answer. It will take me a while to digest. For now only a reply to your question

> Exif tag 4? What's that?

In the command reference of make-profile, I read:

"-i <calibration illuminant>, this is the illuminant the target was shot under, that is the illuminant the targetís RGB values was generated for. Can be specified as an exif light-source name or number, [...] "

So I entered something like 'exif light source number' into Google and came to this page:

http://www.awaresystems.be/imaging/tiff/tifftags/privateifd/exif/lightsource.html

So how would I enter this with the -i flag? -i 4? or -i D55?  or -i 20?

Hoping not to disturb you (much) more in the development of the GUI version ...

torger

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Re: DCamProf - a new camera profiling tool
« Reply #1419 on: January 26, 2017, 02:52:22 pm »

So how would I enter this with the -i flag? -i 4? or -i D55?  or -i 20?

Oh I had forgot about that, you can indeed type "-i 4", or "-i Flash", that's the same thing. However if it complains that it needs spectrum (DCamProf have no spectrum for Flash illuminant in its builtin database, don't think there is a standard for it) you can substitute with -i D55, or use a blackbody spectrum "-i 5500K"
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