Colorthink Pro can any users explain?

[Tony W]

I have been sent the attached from a friend who is just starting to play with Colorthink Pro. Plotting sRGB, Adobe RGB and Prophoto I was surprised to see that the plot for Prophoto was very different than I have seen elsewhere i.e. the wavy lines of the triangle and the fact that I would have thought the plot should extend much further into the green (as seen on other examples).

Any thoughts on what is happening as I am at a loss. I even downloaded the demo v3.03 (I think) to try but that is limited to only the demo profiles

EDIT: Added an image from http://www.luminous-landscape.com/tu...hoto-rgb.shtml figure 3b. This is closer to what I was expecting to see although it was produced in an earlier version of the app

[andrewrodney]

Re: Colorthink Pro can any users explain?

ColorThink is one of the only gamut graphing products doing it right!

http://www.colorwiki.com/wiki/Color_Management_Myths_26-28#Myth_26

[Tony W]

Re: Colorthink Pro can any users explain?

Thank you Andrew. So the first image presented is a truer picture of what is happening within Prophoto and is what you would expect to see?

Therefore what some have dubbed imaginary colours that fall outside of the spectrum locus i.e. the greens in particular as in the second example are incorrect?

Just trying to gain a better understanding of this deep and complex subject

[andrewrodney]

Re: Colorthink Pro can any users explain?

You really want to be viewing these gamuts in 3D! 2D plots are not useful and not accurate.

[Tony W]

Re: Colorthink Pro can any users explain?

Well, I had a chance to play with this app. a little over the weekend. Did not have time to study how to use it but it appears to be an amazing little program with a ton of features (which I do not understand yet!).

3D fantastic (and recording movie!!) which I tried with slightly different results. Attached is the 3D view showing Prophoto only, the second view added sRGB and viewed from the underside. The Prophoto area in mid grey extending outside of the same Prophoto 2D plot shape whereas the sRGB triangle black and red seem aligned. So I still do not understand why the difference.

Also fascinated to see that you can view how an image sits within a particular profile and demonstrate out of gamut very clearly - and yes I know that oog already exists in softproofing LR and PS .

I accept that most camera sensors can record colour that exceed Adobe RGB gamut and I was wondering if and how it would be possible to view the colour gamut (if this is the correct term in this case) of a DSLR sensor within Colorthink - build a profile, shoot a series of images that covered all possible colours and combine or any other way?

[andrewrodney]

Re: Colorthink Pro can any users explain?

I accept that most camera sensors can record colour that exceed Adobe RGB gamut and I was wondering if and how it would be possible to view the colour gamut (if this is the correct term in this case) of a DSLR sensor within Colorthink - build a profile, shoot a series of images that covered all possible colours and combine or any other way?

Not really. It's a very complex subject and issue. You have to feed the raw data to some processing after which you end up with a rendered image in an applied color space. That you can plot. But there's a lot of seasoning and baking going on and it doesn't tell you the gamut of the camera. In fact, cameras don't really have a color gamut per se as we understand it. They have a color mixing function. There are colors we can see it can't record, there are 'colors' it can capture we can't see (hence the quotes) although a lot is done to remove those 'colors'. The profile you build can't be any larger than the target used to build that profile and targets have a gamut limit. Best you can do is encode from the raw processor in both Adobe RGB and something bigger like ProPhoto and compare the gamuts in ColorThink. At least you can see colors that can be processed in a the raw converter that would be clipped if you didn't pick the bigger encoding color space.

[Tony W]

Re: Colorthink Pro can any users explain?

Thanks for the reply on this Andrew. I had been trying to figure how to do this after seeing some plots on the net. First thoughts were to build a profile based on Macbeth checker but then the realisation that the limited color range of the chart limits the profile as you have confirmed.

In a way I am a little relieved that this is difficult to do as I was fearing that it was me having a 'stupid boy' moment and missing the obvious .

[andrewrodney]

Re: Colorthink Pro can any users explain?

Building a profile and looking at the gamut tells you the gamut of the profile, not the device or device's potential. In the case of a camera, this is vastly more difficult and complex than plotting the gamut of a printer. Keep in mind too, by the time a profile 'gets' Lab values to convert into the output color space, it has no idea what the source gamut was. Was it ProPhoto or sRGB? That info is long gone. Each profile package has to make an assumption of the source. So even with a printer, the gamut plot you see from package A vs. package B could be different! Even when plotting this as one should, using Absolute Colorimetric.

[Tony W]

Re: Colorthink Pro can any users explain?

Once again thanks for your input Andrew. What you have said makes sense and has helped me in as much as I feel that while an interesting excercise in itself there are too many variables for me to try and take account and that it is highly likely any testing that I may do would lead me to make false conclusions - there are enough people in the world of imaging doing that already .

Far more useful information can be had as you explained earlier:
"Best you can do is encode from the raw processor in both Adobe RGB and something bigger like ProPhoto and compare the gamuts in ColorThink. At least you can see colors that can be processed in a the raw converter that would be clipped if you didn't pick the bigger encoding color space".

I have already 'played' with monitor profile and how it corresponds to sRGB and also seen the useful out of gamut warning for monitor in Lightroom. Think I need to invest in a wide gamut monitor soon .

I also made a composite image with saturated blues, yellows and reds which when brought into Colorthink and overlayed with various colour spaces clearly demonstrated just how much image data fell outside of Adobe RGB. Next was to have a look at paper profiles and find which suited the image best as far as containing as much original data as possible. That was an interesting excercise which gave me a great deal of useful information - assuming that I was interpreting what I was observing correctly

[andrewrodney]

Re: Colorthink Pro can any users explain?

The gamut warning (overlay) in both LR and Photoshop are buggy. You can load sRGB on an sRGB image and ask to see the OOG overlay and there should be none. But depending on the image, you'll see OOG colors. The overlay predates Photoshop 5 that introduced color management and soft proofing so it's a legacy feature that's pretty useless. What IS useful in LR is showing what colors are OOG based on your display (show me OOG colors in Adobe RGB on my sRGB display). Probably still a tad buggy and inaccurate but at least somewhat useful.

[Tony W]

Re: Colorthink Pro can any users explain?

Thanks for the heads up I did not know that gamut warning were a little suspect!

Must say that I seem to rarely use the gamut warning and have relied on soft proofing to be very close to wysiwig - so far without any problems other than those user induced .

Having said that I have been very much PS oriented for printing and softcopy and only now beginning to see the potential benefits of printing via LR.

[RobertAsh]

Re: Colorthink Pro can any users explain?

Printing in Lightroom is fine and can work well, but there are differences between printing in LR vs. printing in PS. For me, the colors didn't match exactly so I stayed with printing in Photoshop until trying it again recently. Now with PS CS6 vs. Lightroom 4 I'm happier with what I'm getting, the match is noticeably better.

[andrewrodney]

Re: Colorthink Pro can any users explain?

At least on Mac, LR and Photoshop produce identical (measured) results. If you are getting differing results, something is amiss.

[Tony W]

Re: Colorthink Pro can any users explain?

I was never keen in printing from Lightroom due to the fact that there was no soft proofing prior to v4, other than from a plugin which I did not try. Without the facility I too had issues with print matching so I have stuck with PS and found that I could pretty much guarantee the print to screen results.

Now LR has improved considerably in this area. The only thing that throws me a little is output sharpening in the Print module as there seems to be limited settings Low, Standard or High, Media type glossy or matt and setting for image PPI.

Still I suspect that with a little time I will get used to this and having read a few comment by Jeff Schewe extolling the virtues of LR printing then I can absolutely believe that this is a good way to print and may prove better than the old methods I used in PS. I have a great deal of respect for the opinions of Mr Schewe, even so I still just have to prove to myself

[RobertAsh]

Re: Colorthink Pro can any users explain?

At least on Mac, LR and Photoshop produce identical (measured) results. If you are getting differing results, something is amiss.

I'm on a PC. Unfortunately I'm sure that explains a lot of it.... And it is going much better with LR 4 than it did with prior LR versions.