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Author Topic: QPcard 203 - What is the best way to tweak a camera profile?  (Read 3081 times)
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« on: December 05, 2013, 05:35:53 PM »
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I just started using QPcard 203 and its associated application QPcalibration to create camera profiles for my Nikon D5200 to use in Adobe Camera Raw 8.3.

I have used the x-rite colorchecker before but I had a hard time manually tweaking the camera profiles to get a better profile than is available simply by using the colorchecker passport application. I tried using the Adobe DNG profile Editor but couldn't grasp how to use it. So I ended up trying to correct each patch using Photoshop's Curves. This, however, didn't fully workout either because for every patch I was able to successfully correct, another one would get messed up.

Now with the QPcard 203 I am having the same problem. Although the QPcalibration application does a fairly good job of generating a reasonable camera profile, I could really use some insight into how to enhance the profile. Should I try again to use Photoshop's curves to correct easv patch as I have done in the past with the colorchecker? Or should I buy the QPcalibration Adjust plug-in? This plug-in seems interesting but from what I gather from the QPcard website it does not allow individual patch correction.

What do you use?
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MirekElsner
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« Reply #1 on: December 06, 2013, 11:12:45 AM »
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You can purchase a module from them that allows tweaking the profiles, but I just made some LR settings for clarity and vibration and made them a "camera default".

« Last Edit: December 06, 2013, 11:20:02 AM by MirekElsner » Logged
Rhossydd
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« Reply #2 on: December 06, 2013, 12:48:44 PM »
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This, however, didn't fully workout either because for every patch I was able to successfully correct, another one would get messed up.
...........
This plug-in seems interesting but from what I gather from the QPcard website it does not allow individual patch correction.
...........
Before you start trying to edit profiles of any sort you really need to have a good in depth understanding of what you're doing AND have high quality monitoring to judge any edits with. As you've found out it's not just a case of re-working some specific colours as any edit has consequences on other colour ranges.

The QP editing plug-in is probably more than most people ever need and anything more in depth is likely to cause more problems than it solves for the vast majority of users.
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« Reply #3 on: December 06, 2013, 05:37:18 PM »
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No argument there. Most likely i am going to give up any attempt to manually enhance the camera profiles.

As far as I can tell, either with Adobe DNG Profile Editor or with QPcalibration Adjusment, any adjustments one can make to the colors are visually oriented. There is no way to input the correct RGB or Lab values for each patch and expect the other colors to improve as well. It is possible to use Photoshop's curves for such adjustments but correcting one patch throws other patches off-balance.

My displays are pretty well calibrated so I do have a semi-accurate way of judging any color changes but from what I gather each color patch represents a dot on a spider's web and every time you change on of those dots all the other dots that are connected to it change place as well and they don't go to where you need them to go. It's very frustrating.

I have worked with color in computer environments for many years and I have read hundreds of pages on the topics of color management and calibration profiles and so on. But somehow I just don't seem to grasp the gist of it. Many people say the subject is not as complex as it seems but clearly it's above my pay grade.

When it comes to printer profiles, there are companies that you can send a print to and they will return a specific printer profile calibrated to your printer's output. Is there such a service for camera profiles?
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Rhossydd
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« Reply #4 on: December 07, 2013, 03:58:09 AM »
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from what I gather each color patch represents a dot on a spider's web and every time you change on of those dots all the other dots that are connected to it change place as well and they don't go to where you need them to go. It's very frustrating.
You'd probably find it even more more frustrating if you were editing very narrow ranges of colour and getting 'spiky' results.
So far, user built DNG profiles are based on small, affordable targets with limited numbers of colour samples on them. This creates comparatively generalised characterisations and that's probably more helpful for this particular task.
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But somehow I just don't seem to grasp the gist of it. Many people say the subject is not as complex as it seems but clearly it's above my pay grade.
The high end of CM can be eye wateringly complex, but the basics really are pretty simple in practice.
The problem is some folk just get a little knowledge then try to leap up the learning curve when they really don't need to at all. The smart thing is to recognise when enough is enough and to stop worrying about it and get on with shooting and PP.
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When it comes to printer profiles, there are companies that you can send a print to and they will return a specific printer profile calibrated to your printer's output. Is there such a service for camera profiles?
I've not come across anyone offering a DNG profile service, but it's not difficult to work out why;
To make a DNG camera profile you need a reference chart, either a QP or CC24, neither are particularly expensive and both come with their own free software. Offering a service where you send out a reference chart to a customer and ask them to return it after use, would be expensive and difficult to implement, so difficult to make much(any) money out of. Anyone who owns a chart already has the tools to build a profile with and the software is hardly difficult to use.

Once you get to this level of camera profiling, results become rather subjective.
The exception is if you're shooting in a precisely controlled situation with steady stable lighting, most of us aren't.
Try some different software, make some profiles and choose the one you like most. Chasing numbers on this can be frustrating and futile.
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bill t.
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« Reply #5 on: December 17, 2013, 10:31:26 PM »
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Editing profiles is the next best thing to not using profiles at all but instead relying on the adjustments in the default printer dialogue.  We use profiles for accuracy, assuming the carefully measured data is being used to its best avail.  A profile is, in theory, either correct or not.  Edit not, merely discard.  Admittedly some profiling systems work better than others, and if you're not getting profiles you like, you can opt for a better system or hire somebody who has one.  Or chose a more gamut-rich media.  Gamut impoverishment is a major cause of unhappiness in otherwise correctly color managed systems, and art media is the biggest offender.

I had a print profiling system long ago that came with an editor, with adjustments for all the basic parameters.  The profiling hardware system was so bad, the manufacturer supplied the editor to try to make the product somehow acceptable, or that's my theory.  Was it Datacolor?  Don't get me started.  Can't remember.  But those miserable edited profiles weren't much use in the long run.  I could tweak profiles for particular categories images if I had the inclination, but the time spent monkeying with those profiles would have been better spent in Photoshop and then printing with the media manufacturer's canned profiles.
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Rhossydd
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« Reply #6 on: December 18, 2013, 02:59:44 AM »
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... if you're not getting profiles you like, you can opt for a better system or hire somebody who has one....
In this case, specifically DNG camera profiles, I believe that there are only three systems available to make the profiles;
X-Rite Passport
Adobe DNG profile editor
QP Card
So unlike building icc profiles, there's no alternative exotic solution high end solutions.

One also needs to be careful not to use potential misleading words like 'correct' and 'accurate' or you'll just start yet another thread detailing why these sort of descriptions are wrong in most usage.

Try all the packages, choose the profile you like the best for a shot and move on.

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Vladimirovich
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« Reply #7 on: December 18, 2013, 08:51:14 AM »
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In this case, specifically DNG camera profiles, I believe that there are only three systems available to make the profiles;
X-Rite Passport
Adobe DNG profile editor
QP Card
actually 4 ... text editor to type the code and dcptool to compile it into .dcp  Cheesy
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Rhossydd
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« Reply #8 on: December 18, 2013, 10:02:39 AM »
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actually 4 ... text editor to type the code and dcptool to compile it into .dcp  Cheesy
No, if we're being pedantic dcptool is an editor and doesn't make DNG profiles. It just takes profiles made from either of the above 3 and changes them.

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Vladimirovich
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« Reply #9 on: December 18, 2013, 11:30:35 AM »
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No, if we're being pedantic dcptool is an editor and doesn't make DNG profiles. It just takes profiles made from either of the above 3 and changes them.
nope, nobody prevents me from typing the profile from scratch w/o decompilation first and then compile... certainly that will be painful excercise, because you will need to do calculations elsewhere.
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Rhossydd
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« Reply #10 on: December 18, 2013, 12:02:22 PM »
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nobody prevents me from typing the profile from scratch
But that's not building a camera profile.
Just typing created data into dcptool just gives you an abstract profile.

The whole point about profiling is to characterise a specific device. You need to use camera derived data.
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