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Author Topic: Manually modify or build an ICC profile?  (Read 2465 times)

NAwlins_Contrarian

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Manually modify or build an ICC profile?
« on: February 07, 2018, 06:25:27 PM »

Is there a way--that is cheap and not hugely complicated--to manually modify or even build an ICC profile? And by manually, I mean without a spectrophotometer (ColorMunki Photo or similar). In my specific case, I have a profile for the printer + ink + paper combination that produces pretty good results for black and white prints. However: (1) overall there’s a slight olive-green cast, which I figure with modifications to the individual R, G, and B and curves and some trial and error I can probably counteract; and (2) the deepest shadows are a bit crushed, i.e., there’s very little deep shadow detail. Instead of tweaking every image to counteract these issues, I’d rather develop a standardized way to make prints that look, subjectively to me, ‘right’. Obviously I could have a custom ICC profile made, but even if it is perfectly technically correct, that doesn’t necessarily replicate what looks right to my eyes.

If I do it as a curves adjustment in Lightroom or DxO PhotoLab or whatever, those adjustments don’t really translate to other software, may complicate other image-specific adjustments I’d like to make, and may be slightly laborious to make. On the other hand, if I modify an existing ICC profile or build a new one to get the prints I want, using it thereafter should work quickly and easily, regardless of software, without complicating other adjustments.

To be clear, I’m under no illusion that I can make color photos come out correctly through such a procedure. My ambition is limited to neutralizing B&W and opening the deepest shadows a bit.

So can you recommend a way to do this?
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Mark D Segal

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Re: Manually modify or build an ICC profile?
« Reply #1 on: February 07, 2018, 07:14:00 PM »

You'd need profile editing software and considerable experience using it. Most colour management professionals are wary of it. If you are getting a cast with the profile you are using, there is either something wrong with the profile or something wrong with the way you are using it. Probably better to get down to root causes and then see whether reprofiling would be the best approach. Once you have a profile that behaves reliably to reproduce the file values more or less correctly, you can then with confidence edit the photos to give them the look you consider correct - provided your monitor is also telling you the truth.
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Mark D Segal (formerly MarkDS)
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Doug Gray

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Re: Manually modify or build an ICC profile?
« Reply #2 on: February 07, 2018, 07:50:41 PM »

You'd need profile editing software and considerable experience using it. Most colour management professionals are wary of it. If you are getting a cast with the profile you are using, there is either something wrong with the profile or something wrong with the way you are using it. Probably better to get down to root causes and then see whether reprofiling would be the best approach. Once you have a profile that behaves reliably to reproduce the file values more or less correctly, you can then with confidence edit the photos to give them the look you consider correct - provided your monitor is also telling you the truth.
I agree.

However, there is one possible approach using Argyll and a scanner or camera. These aren't very good for color accuracy but should track neutrals quite well. So printing a target with a lot of neutrals and near neutrals might well produce a usable profile for B&W. But colors would likely be much less accurate and the further the colors are from neutral, the worse the profile.

An approach like this would work on printers as I've photographed neutral gradients and examined the color shifts in comparison to spectrometer readings and they were quite good. Not so good outside of neutrals but that's all you need for a good B&W profile.

http://argyllcms.com/doc/Scenarios.html#PP4


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Mark D Segal

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Re: Manually modify or build an ICC profile?
« Reply #3 on: February 07, 2018, 07:53:53 PM »

I agree.

However, there is one possible approach using Argyll and a scanner or camera.


OK, but the O/P said "not hugely complicated". How would you categorize this approach, taking into account both the techniques and the limitations you mention?
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Mark D Segal (formerly MarkDS)
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Doug Gray

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Re: Manually modify or build an ICC profile?
« Reply #4 on: February 07, 2018, 08:18:03 PM »

OK, but the O/P said "not hugely complicated". How would you categorize this approach, taking into account both the techniques and the limitations you mention?

Well, it's the least complicated approach I can think of. Tweaking ramps is also possible using ICC's profile explorer at www.color.org. You can output a BtoA1 table with the various parts in text format. Load them in Excel, adjust them, and reload them into the profile. That's the next simplest way I know of and it aligns with the OP's thinking. That scares me a lot more than Argyll which seems moderately straightforward. OTOH, if the OP wants to spend money there might be  Profile Maker 5 out there somewhere and it has a profile editor. I've played with it years ago. I can say unless one wants to do it just for the joy of experimenting, far and away the best approach is just get a custom profile. If neutrals are a problem have one made with a large target patch set.
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DP

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Re: Manually modify or build an ICC profile?
« Reply #5 on: February 07, 2018, 08:45:00 PM »

And by manually, I mean without a spectrophotometer (ColorMunki Photo or similar).

time x money = cheaper to buy spectrophotometer, no ?
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Mark D Segal

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Re: Manually modify or build an ICC profile?
« Reply #6 on: February 07, 2018, 08:55:38 PM »

............ far and away the best approach is just get a custom profile. If neutrals are a problem have one made with a large target patch set.

Yup!
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Mark D Segal (formerly MarkDS)
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nirpat89

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Re: Manually modify or build an ICC profile?
« Reply #7 on: February 07, 2018, 11:52:27 PM »

Considering how messy it is to modify the profile which does not sound like a good manual trial and error method to tweak, short of getting your own spectrophotometer I recommend use of a step wedge in combination with either modifying the individual R, G, B channels or by use of hue or color filters to obtain the desired results.  I had the same problems with canned paper profiles earlier on and I dug into my experience with color printing where the color matching was done thru eyeballing and dialing in C, M, Y filters and came up with a correction curve layer for each paper I was using.  Worked fine (enough) until I got a new printer.   

Edit:  By "color printing" above meant making ektachrome paper prints from sildes in the darkroom with an enlarger with C, M, Y filters.
« Last Edit: February 09, 2018, 07:00:02 AM by nirpat89 »
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Rhossydd

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Re: Manually modify or build an ICC profile?
« Reply #8 on: February 08, 2018, 01:33:40 AM »

time x money = cheaper to buy spectrophotometer, no ?
Just get a custom profile made. £15 and job done.

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NAwlins_Contrarian

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Re: Manually modify or build an ICC profile?
« Reply #9 on: February 09, 2018, 11:02:54 PM »

Thanks everyone for the responses. Perhaps I should have stated more clearly that to a significant extent I enjoy tinkering, and also would appreciate learning some about ICC profiles in the process. Also, the idea to tweak the profile hit me when I realized how some B&W prints looks relatively neutral or visibly non-neutral depending on the light used for viewing--and I thought I could produce tweaks for differing conditions in a way that a 'neutral' profile could not. Last but not least, further experiments have shown me that simply using perceptual instead of relative colorimetric rending intent goes a good way toward resolving the crushed shadows--I did not realize how much difference it could make to neutrals (and I usually prefer relative colorimetric for color prints).

Quote
An approach like this would work on printers as I've photographed neutral gradients and examined the color shifts in comparison to spectrometer readings and they were quite good. Not so good outside of neutrals but that's all you need for a good B&W profile.
http://argyllcms.com/doc/Scenarios.html#PP4

Thanks, I will have to read that.

Quote
Tweaking ramps is also possible using ICC's profile explorer at www.color.org. You can output a BtoA1 table with the various parts in text format. Load them in Excel, adjust them, and reload them into the profile. That's the next simplest way I know of and it aligns with the OP's thinking.

Specifically, which program / download do you mean by "ICC's profile explorer"? I looked at http://www.color.org/opensource.xalter and http://www.color.org/profileview2.xalter, but did not see anything that obviously matches that. I downloaded and installed ICC Profile Inspector, and it at least does not appear to be able to do anything like that--did I miss it?

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time x money = cheaper to buy spectrophotometer, no ?

Quote
Just get a custom profile made. £15 and job done.

If this were a business or professional proposition, definitely buy a spectrophotometer or get custom profiles made (which I'm on the verge of doing for a couple of papers anyway). But I'm curious and want to tinker. Shortly after the Earth cooled, I used to enjoy using Apple's ResEdit tool to tweak fonts and various other components, sometimes for a real purposes and sometimes just to explore / for my own amusement. In part, I have the same idea / desire here.

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Doug Gray

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Re: Manually modify or build an ICC profile?
« Reply #10 on: February 09, 2018, 11:26:06 PM »

Specifically, which program / download do you mean by "ICC's profile explorer"? I looked at http://www.color.org/opensource.xalter and http://www.color.org/profileview2.xalter, but did not see anything that obviously matches that. I downloaded and installed ICC Profile Inspector, and it at least does not appear to be able to do anything like that--did I miss it?

If this were a business or professional proposition, definitely buy a spectrophotometer or get custom profiles made (which I'm on the verge of doing for a couple of papers anyway). But I'm curious and want to tinker. Shortly after the Earth cooled, I used to enjoy using Apple's ResEdit tool to tweak fonts and various other components, sometimes for a real purposes and sometimes just to explore / for my own amusement. In part, I have the same idea / desire here.

Well, I'm very much the tinkerer too but find a spectrophotometer indispensable in verifying what I try. Too many rabbit holes otherwise.

Yes, my bad. It's Profile Explorer which you found. To extract the relevant ramps and tables, open a printer profile, select one of the tables. For instance the Relative Colorimetric B2A1 table which goes from the PCS (in Lab) to the printer's RGB device space. Then select export and it will write all the tables in a directory of your choice. The Import button does the reverse.

You should download the ICC Specification which is necessary to make sense of the tool. They also have the source code should you want to go into its innerds but for what you want to do the import/export should do the job.
« Last Edit: February 10, 2018, 12:01:51 AM by Doug Gray »
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Rhossydd

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Re: Manually modify or build an ICC profile?
« Reply #11 on: February 10, 2018, 05:19:28 AM »

But I'm curious and want to tinker. Shortly after the Earth cooled, I used to enjoy using Apple's ResEdit tool to tweak fonts and various other components, sometimes for a real purposes and sometimes just to explore / for my own amusement. In part, I have the same idea / desire here.
I can understand that, but delving into editing color profiles is a magnitude more complex than tweaking fonts.
There is software to do it, but it's mostly part of expensive suites of profiling software that are either very expensive or very complex.

If you back read through this forum you'll read many cautions about editing profiles from the most experienced practitioners. You won't read many success stories.

You'll also learn that there are few resources that help understanding the processes involved. The learning curve is almost vertical.

So the simple answer to your original question "Is there a way--that is cheap and not hugely complicated--to manually modify or even build an ICC profile?" is no.
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digitaldog

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Re: Manually modify or build an ICC profile?
« Reply #12 on: February 11, 2018, 10:33:26 AM »

Well, I'm very much the tinkerer too but find a spectrophotometer indispensable in verifying what I try.
Imagine going to a job site where a house is being built and not a single worker has a ruler. :'(
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Andrew Rodney
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Re: Manually modify or build an ICC profile?
« Reply #13 on: February 14, 2018, 12:43:24 PM »

It sounds like the OP wants a profile which is objectively inaccurate, tweaking colors and dark tones to make prints come out looking good.  What I think most responders are suggesting is to make a profile which is objectively accurate, do the same for the monitor, then make the tweaks to adjust colors and dark tones through Lightroom or other editing program.  The end result should be the same, but the standard approach will be more predictable and useful in the long run.  If you end up making the same tweaks to most images, editing programs will let you save those tweaks as a predefined action, so they can be applied quickly to a new image.
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Doug Gray

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Re: Manually modify or build an ICC profile?
« Reply #14 on: February 14, 2018, 01:18:54 PM »

It sounds like the OP wants a profile which is objectively inaccurate, tweaking colors and dark tones to make prints come out looking good.  What I think most responders are suggesting is to make a profile which is objectively accurate, do the same for the monitor, then make the tweaks to adjust colors and dark tones through Lightroom or other editing program.  The end result should be the same, but the standard approach will be more predictable and useful in the long run.  If you end up making the same tweaks to most images, editing programs will let you save those tweaks as a predefined action, so they can be applied quickly to a new image.
Exactly, it also allows changing printers w/o losing the desired tweaks.
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Joe Towner

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Re: Manually modify or build an ICC profile?
« Reply #15 on: February 28, 2018, 01:59:26 PM »

It may be worth renting a profiler - https://www.lensrentals.com/rent/x-rite-i1studio-spectrophotometer

Do a full calibration and see what the results are like.
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NAwlins_Contrarian

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Re: Manually modify or build an ICC profile?
« Reply #16 on: March 03, 2018, 09:06:30 PM »

Thanks everyone for the replies. Upon review, and 'opening up' some profiles with the suggested program and your comments have persuaded me that this is unlikely to be a productive or even informative approach.

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It sounds like the OP wants a profile which is objectively inaccurate, tweaking colors and dark tones to make prints come out looking good.

More precisely, I want to tweak an existing profile to give what my eyes see as neutral when viewing under different lighting conditions. I have experimented with ostensibly-neutral prints under tungsten, fluorescent, and sun light, and using the selenium-emulation settings in both DxO FilmPack and (through Lightroom) Nik Silver Efx. I'm still not entirely happy with what I'm getting, but this is a learning experience. And back in my wet darkroom days, I never messed with selenium, preferring to avoid entirely the toxicity issues.

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It may be worth renting a profiler - https://www.lensrentals.com/rent/x-rite-i1studio-spectrophotometer
Do a full calibration and see what the results are like.

I may just do that. I've rented from LensRentals a couple of times before, was aware that they rent the ColorMunki Photo (and I see now, also the i1 Studio), and have a LensRentals credit burning a hole in my electronic pocket. What is not clear to me is whether it will let me 'bake in' the tweaks I want.
« Last Edit: March 03, 2018, 09:14:47 PM by NAwlins_Contrarian »
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