DCamProf - a new camera profiling tool

[torger]

Just released v0.6.2, now test-profile supports ICC and you can make ICC plots, that wraps up the ICC support which is now at the same level as DCP. In the usual place: http://www.ludd.luth.se/~torger/dcamprof.html

[AlterEgo]

0.6.2 build for Windows (mingw = dcamprof.exe + libgomp_64-1.dll) : https://app.box.com/s/t851von5samj5tq8hzyw5qtontd8z3zo

[Bart_van_der_Wolf]

Thanks to both Anders and 'AlterEgo' for the updated code and binaries.

Cheers,
Bart

[torger]

Noticed I broke some of the old plot code in 0.6.2 when ICC plots were added. Will fix that and make some whitepoint handling improvements to next patch release.

[torger]

Just released v0.6.3, fixed the plot bug, added two more error vector plots, better whitepoint preservation handling of the LUT.

Now I don't have any particular urgent things on the todo list left, so hopefully I can keep it in just-fixing-bugs mode for a while.

[AlterEgo]

0.6.3 build for Windows (mingw = dcamprof.exe + libgomp_64-1.dll) : https://app.box.com/s/gtli840m59r5yd1yi9bzjgaub1bo4gdf

[torger]

Slow day at work so I've done some testing of matrix optimization, found a bug in the overall printed stats which is fixed in 0.6.4 now out. I also adjusted the matrix optimization very slightly and updated the docs on weighting a bit.

In practice weighting does not seem to have that big impact on low patch targets like the CC24, weighting results can for those appear a bit random, eg if you reduce importance on say lightness it may sometimes actually improve lightness accuracy rather than the other way around. For those the "weighting" is sort of already done from the choice of patches, by excluding colors you get better precision on the colors you include.

Weighting behaves more predictably on larger patch count targets with higher saturation patches like a glossy IT-8 target.

One interesting result I found is that it's often a good idea to reduce importance of chroma (saturation), this will naturally push the matrix towards lower saturation as it gives more room to fine-tune hue.

[AlterEgo]

0.6.4 build for Windows (mingw = dcamprof.exe + libgomp_64-1.dll) : https://app.box.com/s/bervrhj671j70l7e2fuca9q9ug9sw9zp

[torger]

There is some problem with the LUT causing some purple colors to be pulled towards deep blue. I'm investigating. Sounds like kind of the reverse of "blue turns purple" lab problem, but there should be no such stuff... but well, it's something weird going on. Matrix profiles seems unaffected.

I've also noted that DCamProf produces saturated profiles compared to typical bundled profiles. I'm not sure why. If saturation is correct is hard to verify by eye, but it seems like DCamProf could be the more correct, while bundled profiles are often desaturated to not become too saturated when a film-curve is applied. I haven't thought about this before.

Maybe I'll have to add a feature that makes it possible to adapt the profile to a certain film-curve. You can't get perfect accuracy with that as it will depend on where on the S-curve the color is how saturated it will be, but I guess one would adapt assuming the color is in the midtone range.

Has anyone any input on this, that is how profiles should relate to the film curve? Today DCamProf makes "corrrect" profiles for linear curve, which means saturation will increase to higher levels than real-world when an S-curve is applied.

[torger]

There is some problem with the LUT causing some purple colors to be pulled towards deep blue. I'm investigating. Sounds like kind of the reverse of "blue turns purple" lab problem, but there should be no such stuff... but well, it's something weird going on. Matrix profiles seems unaffected.

There was no LUT problem, what happened was that I got some extreme stretching in the LUT, and then bad things can happen if the white balance is set to a bit different from what the profile was designed for. When white balance is changed, the input colors to the LUT shift positions and if you have some extreme local stretches it can suddenly get into the position of a neighboring color and get stretched away.

I'm experimenting with high saturation custom targets when I got this problem. I'm still a bit surprised that the LUT had to stretch as much to hit the colors, I'm getting a quite different result when using SSF on the same target, so I still have some things to investigate.

Anyway, moving the white balance back and forth in the raw converter while looking how the color change is a good "sanity check" of a LUT profile. Preferably use a shot with many colors, a color checker of some sort. If one or more colors suddenly changes a lot faster than others you probably have too strong stretch in the LUT. Of course you can also plot the LUT to see these problems.

[Tim Lookingbill]

There is some problem with the LUT causing some purple colors to be pulled towards deep blue. I'm investigating. Sounds like kind of the reverse of "blue turns purple" lab problem, but there should be no such stuff... but well, it's something weird going on. Matrix profiles seems unaffected.

I've also noted that DCamProf produces saturated profiles compared to typical bundled profiles. I'm not sure why. If saturation is correct is hard to verify by eye, but it seems like DCamProf could be the more correct, while bundled profiles are often desaturated to not become too saturated when a film-curve is applied. I haven't thought about this before.

Maybe I'll have to add a feature that makes it possible to adapt the profile to a certain film-curve. You can't get perfect accuracy with that as it will depend on where on the S-curve the color is how saturated it will be, but I guess one would adapt assuming the color is in the midtone range.

Has anyone any input on this, that is how profiles should relate to the film curve? Today DCamProf makes "corrrect" profiles for linear curve, which means saturation will increase to higher levels than real-world when an S-curve is applied.

Since you're describing visually what DCamProf does to saturation and hue shifting in purples toward blue, have you considered constructs within the display profile as influences?

Haven't seen this mentioned here.

Also your point about uneven saturation levels across a wide range of colors as a sanity check also happens with my custom DNG profiles on some scenes. One slight tweak to WB and things shift unexpectedly saturation and luminance wise on certain colors which is why I've questioned ICC display profile influences.

I've often thought there needs to be more accurate descriptors of saturation appearance connected to the math under the hood because your description indicates a pattern of behavior with certain colors that suggest complexities that haven't been defined thoroughly mathematically. Maybe there needs to be a mathematical formula that takes into account human adaptation on saturation appearance separate from WB influences.

[torger]

Screens with profiles, or factory builtin profiles (to emulate sRGB for example), can indeed sometimes have ugly nonlinearities that can make images appear to have problems when there are none, I've seen that. However I move between several computers, some without screen profiles, and I also know the profile quite well of my own screen (shaper profile designed with Argyll) so there was no such problem here.

The problem was as described in the last post, due to that there was a poor fit the LUT had to stretch a lot, and then the results become very white-balance dependent. If the white balance is not exactly as the profile expects the LUT can drag the wrong colors which happened in this case.

The next problem is why there was a poor fit and I'm still investigating that. I think there was some measurement problem, either in my XYZ reference measurements or in the test target photo, or both. I'm starting to suspect that high saturation patches as I have on my test target may not be a good idea when you shoot a target as it seems like the impact of small measurement errors becomes large, while lower saturation targets are much more robust. This is still just a theory though which I need to verify.

[jwlimages]

If this is too far off topic, my apologies…

Seems like an opportunity for someone here: create a good DNG profiling application, put a Mac interface on it (please!), allow for the user to load custom measurements from his/her Color Checker or CC Passport target, make it robust enough to handle larger-size DNG's (Pentax 645z). I would pay good $$ for this, and I suspect many others would, too.

Seems like there would be no competition for such a product - X-rite's Passport software is not only showing its age, but apparently will not receive any further development (users over on Pentax user forum claim to have been told this directly by X-rite staff).

John

JWL Images
Emeryville, CA

[AlterEgo]

If this is too far off topic, my apologies…

Seems like an opportunity for someone here: create a good DNG profiling application, put a Mac interface on it (please!), allow for the user to load custom measurements from his/her Color Checker or CC Passport target, make it robust enough to handle larger-size DNG's (Pentax 645z). I would pay good $$ for this, and I suspect many others would, too.

Seems like there would be no competition for such a product - X-rite's Passport software is not only showing its age, but apparently will not receive any further development (users over on Pentax user forum claim to have been told this directly by X-rite staff).

John

JWL Images
Emeryville, CA

and why kind of UI you are missing exactly - because everything else is already there and works (on Mac too) ?

[torger]

If this is too far off topic, my apologies…

Seems like an opportunity for someone here: create a good DNG profiling application, put a Mac interface on it (please!), allow for the user to load custom measurements from his/her Color Checker or CC Passport target, make it robust enough to handle larger-size DNG's (Pentax 645z). I would pay good $$ for this, and I suspect many others would, too.

Seems like there would be no competition for such a product - X-rite's Passport software is not only showing its age, but apparently will not receive any further development (users over on Pentax user forum claim to have been told this directly by X-rite staff).

It's probably not a bad idea, in a distant future (1 year plus) I might make a commercial GUI version of DCamProf (keeping command line open source), with the added feature to make custom hand-tuning to create "looks" (for that I think a GUI is really needed). I personally don't like having the look in the profile but the majority of users do, so to make a commercial I think that is a must-have feature. Still it would not be a huge seller, there's a reason X-rite staff is not developing their product further, there's more money to make on other products. I think most are using Adobe DNG Editor and are satisfied with that.

I also think one problem with commercializing a product is that making camera profiles beyond the very basics is relatively hard. Making a camera profile with a look requires a good eye for color and taste, and quite some technical understanding of camera limitations too. Looking at X-rite's products they are very focused on ease-of-use, so one reason they're not developing their profiling product further may be that it would be a "too complicated" product, so maybe it's not only about money-making potential...

[AlterEgo]

here's more money to make on other products.

I read just recently somewhere - poster alleged that he was told by a big B&M photo shop that they sell to the tune of 10Ks xrite passports annually (), so indeed if that is the case

[AlterEgo]

Making a camera profile with a look requires a good eye for color and taste

so the business is to sell canned looks actually - a lot of companies do (even in non profile form)

[AlterEgo]

there's a reason X-rite staff is not developing their product further

they killed profilemaker ! 

[jwlimages]

It's probably not a bad idea, in a distant future (1 year plus) I might make a commercial GUI version of DCamProf (keeping command line open source), with the added feature to make custom hand-tuning to create "looks" (for that I think a GUI is really needed).

--  Yes, I follow your reasoning here, but I too am not fond of this/would have no use for "looks" like that - kind of like all the Lightroom "presets" people are trying to sell. Yes, it's a one-button procedure, but the results generally suck, IMHO.

Yes, X-rite killed ProfileMaker, their software generally leaves a lot to be desired - I wonder if this isn't just their longtime corporate culture reasserting itself. Seems like they were always thought of as an outfit that made good hardware/not-so-good software. Once Gretag-MacBeth got gobbled up, maybe it was only a matter of time before that company's software skills (developer/engineers?) were gone.

Still I would dearly love to see a decent DNG-profile generating app, that could accept custom measurements & deal with larger DNG files. Something to help me render colors predictably, hopefully relatively "accurately" - all that business of simulating a Kodachrome look, or whatever, can easily be handled in Photoshop.

Just a thought, anyway…

Thanks for your efforts.

John

[AlterEgo]

Still I would dearly love to see a decent DNG-profile generating app, that could accept custom measurements & deal with larger DNG files.

why "would" - what prevents you from using dcamprof right now this moment ?