DCamProf - a new camera profiling tool

[Iliah]

so _4_ spectrophotometers later (colormunki, i1Pro2, 2 x Spectrolino - I got one more just in case) here goes XRite

no, they are still not willing to share the numbers, but it seems they are willing to exchange the target...

Jan 2014 production only? Or maybe not...

[AlterEgo]

Jan 2014 production only? Or maybe not...

speaking about the proverbial patch (tuft) of wool from a sheep...

[Iliah]

speaking about the proverbial patch (tuft) of wool from a sheep...

Is yours from Jan 2014?

[AlterEgo]

Is yours from Jan 2014?

yes and "they" (CSR at least - it is the same name since the beginning) know that - they asked about the edition even during the first round - this is 3rd round of exchange about the matter already, as I asked somebody else couple of weeks ago to help me to get to the right people in X-Rite (and may be that /person/ helped actually /just in case - thank you, Joshua/)

[Iliah]

yes and "they" (CSR at least - it is the same name since the beginning) know that - they asked about the edition even during the first round - this is 3rd round of exchange about the matter already, as I asked somebody else couple of weeks ago to help me to get to the right people in X-Rite (and may be that /person/ helped actually /just in case - thank you, Joshua/)

So, they knew it is Jan 2014 beforehand. Does not add much credibility to their "only".

[AlterEgo]

So, they knew it is Jan 2014 beforehand. Does not add much credibility to their "only".

at least it seems I have a chance to get a "proper" target, will see how it measures then... albeit if they state that the formulation was changed it still leaves the question about some /data/ basis vs which to compare your own measurements to see if something is out of the ordinary (unless they have a stock of legacy targets from the old days somewhere), like with this one from Jan 2014 - I am curious to see how all the devices I can use will measure the black patches if I /hopefully/ receive a replacement...

[torger]

Released v0.8.1, fixed a critical bug in the tone reproduction operator and improved its extreme highlight rendering

[AlterEgo]

0.8.1 build for Windows (mingw = dcamprof.exe + libgomp_64-1.dll + HTML & PDF manual / = copy of Torger's web page and the same converted to PDF /) : https://app.box.com/s/sx1f8asu3ze7zxmnwa96cixjcwceqsec

[torger]

Released v0.8.2 where I added the neutral tone reproduction support also for ICC profiles.

[AlterEgo]

Released v0.8.2 where I added the neutral tone reproduction support also for ICC profiles.

JFYI for few users my windows binaries, I will not be able to build this till this evening (EST)...

[Bart_van_der_Wolf]

JFYI for few users my windows binaries, I will not be able to build this till this evening (EST)...

Even with the delay, much appreciated. And thank you Anders, for the ICC support.

Cheers,
Bart

[torger]

Even with the delay, much appreciated. And thank you Anders, for the ICC support.

I haven't been able to test it yet in Capture One as my license is on a computer in a different location, and there was some mess with trial version on this box so I gave it up. It should work though, otherwise I'll fix it when I get the opportunity.

If you want an ICC profile designed with the neutral tone reproduction operator it will currently always be applied directly in the LUT, which for C1 means that you must always use the profile with the linear curve as the curve is applied in the LUT itself. I've tested it in RT and it works well there, and I think it should work well also for C1 but I'm not 100% sure as I've not been able to test yet. I may in the future make it possible to not include the curve in the LUT, but in that case one have to know which working space C1 is using for applying the curve and that seems to vary between cameras in some way I don't fully know how it works.

When mentioning RT (RawTherapee) where I'm also a contributor I've today pushed a patch that makes looktables be applied after exposure as they should. Before RT could not handle looktables properly. This means that if you get a build made July 6 or later you will get excellent control of DCamProf DNG profiles, in one and the same profile you can have a matrix-only profile, refined with a HusSatMap to a more accurate colorimetric result, and then a curve and looktable on top for the neutral tone operator, each element can be toggled directly inside RT depending on how you want to use the profile.

[AlterEgo]

0.8.2 build for Windows (mingw = dcamprof.exe + libgomp_64-1.dll + HTML & PDF manual / = copy of Torger's web page and the same converted to PDF /) : https://app.box.com/s/t0b7hd7ufvccsvgntr3vt6e3vtouxmsj

[Alexey.Danilchenko]

That's super-cool, I'd love to see some photos when you have it all working!

I assembled my monochromator setup at last with all bits (it took long time to complete and test). Yesterday made a test run to calibrate and took spectral sensitivities of the Kodak ProBack645 (lots of data to process and not sure that it went ok yet - I think I need some adjustments to my light measurement device on Arduino), the transmittance spectra of all filters (IR, AA etc) and transmittance spectra of almost all lenses. I now need to process it all and build a library and experiment with simulation for the camera readings of a target.

That's how the setup looks (sorry for the pictures - took them with mobile).

Monochromator with the integrating sphere and with a lightmeter on Arduino:






And switched on (light is very dim - it was too dark without any light for a photo and nothing visible with full light on):





The monochromator itself used in my setup is expensive if bought from new but they could be found as a part of the industrial assembly of Luxtron/Lumasense 1108 (they can be found on ebay quite cheap every now and then). The integrating sphere was part of the assembly from Photonis XP3112/PB. Arduino device I built and coded myself and as for the light source - any with goose neck fiber optic cable will do (plenty cheap on eBay). The whole setup generally cost a lot less than a new ColorChecker SG.

The calibration procedure is simple. I pre-heat the light source (halogen 150W Philips) to stabilize, turn on my instrument, and then walk through the spectrum (400-730nm) at 5nm intervals measuring spectra with i1Pro in high res mode in Argyll (all in a dark room with insulation of i1Pro and integrating sphere) and record the readings off the Arduino meter (just upper ones - it is just a reading of the full visible range photodiode). All this is then placed in a calibration table and used with readings of the light meter when taking the shots with camera to adjust the light source drifts (and there are definitely drifts there as I discovered).

Knowing the transmission spectra of lenses and filters, it should be possible to make the simulation of a target shot by camera in a certain light (will need to do that experiment with real target).

[AlterEgo]

I assembled my monochromator setup at last

beautiful !

[torger]

Wow Alexey, great to see!

[Iliah]

Since you already employed Arduino, I would be adding a rotary encoder (like those Sparkfun are carrying) to log the wavelengths. Maybe a stepper motor too.
Saying "record the readings off the Arduino meter (just upper ones - it is just a reading of the full visible range photodiode)" - how do you mean "upper" - those "Ful 28" on the second image?

[Alexey.Danilchenko]

Since you already employed Arduino, I would be adding a rotary encoder (like those Sparkfun are carrying) to log the wavelengths. Maybe a stepper motor too.
Saying "record the readings off the Arduino meter (just upper ones - it is just a reading of the full visible range photodiode)" - how do you mean "upper" - those "Ful 28" on the second image?

Perhaps one day - I'd like to get the feeling of this whole thing first . For now I employ a very "sophisticated" method of using pocket torch between the measurements to adjust the dial

Re photodiode - I used Adafruit lux sensor (same as sparkfun uxing tao chip) that has 2 diodes in a package (full visible and ir). I used calculations from their library to calculate 4 values: full range(raw reading), ir,fill-ir and calculated lux (just for fun). I'm using fuĺl range reading - is that wrong?

[Iliah]

> Perhaps one day - I'd like to get the feeling of this whole thing first

I agree. Just saying how I do those things (though I use Linux boards, not Arduino, unless I need real time - and that case I use small Atmel or PIC boards or chips as slaves to some Linux board; humidity sensors in my film drying cabinet would be one of the examples, power supply control to stabilize light is another one).

> I used Adafruit lux sensor (same as sparkfun uxing tao chip) that has 2 diodes in a package (full visible and ir). I used calculations from their library to calculate 4 values: full range(raw reading), ir,fill-ir and calculated lux (just for fun). I'm using fuĺl range reading - is that wrong?

Not at all, it is perfectly OK. I was just asking because your reference to "upper" did not came clear to me. What you did with a photodiode is a classic setup, same one I use - though I use a different diode. Never occurred to me to try a TAOS chip in this application.

[Alexey.Danilchenko]

> I agree. Just saying how I do those things (though I use Linux boards, not Arduino, unless I need real time - and that case I use small Atmel or PIC boards
> or chips as slaves to some Linux board; humidity sensors in my film drying cabinet would be one of the examples, power supply control to stabilize light is another one).

I am not that experienced with hardware so Arduino seemed a no brainer for me .

> power supply control to stabilize light is another one).

I am quite interested in that (assuming you are talking about halogen sources) - would you point me in a right direction?

> Not at all, it is perfectly OK. I was just asking because your reference to "upper" did not came clear to me. What you did with a photodiode is a classic setup,
> same one I use - though I use a different diode. Never occurred to me to try a TAOS chip in this application.

I had the chip assembly left from experiments with SLR/n nonlinearities in the last 1/6 stop (we discussed it a while ago if you remember) so it was an easy choice.

I had extracted my ProBack spectras tonight and they are rubbish. The first attempt went astray so I will need to redo it. I'd need to correct a few things as well:
- I used Kodak firmware capacity to subtract black on long exposures but it still generates a lot of noise so will need to do black subtraction myself
- have not closed viewfinder (I know its stupid but I forgot) for the 400-450 range so blue is captured quite badly
- I need to invent something to connect camera to integrating sphere more tightly to prevent even slightest leaks
- And add baffle to either entry from monochromator or photodiode (the latter seem to be influenced a bit by entry light positioning and sits opposite exit from monochromator albeit offset a bit).