"The Devil's Advocat on Color Correction"

Comments and discussions about 8bf plugins which can be use in various applications like Photoshop, Paint Shop Pro or Photo-Paint
HaraldHeim
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"The Devil's Advocat on Color Correction"

Postby HaraldHeim » Tue Mar 04, 2003 2:41 pm

This thread is intened for people who would like to comment on my article "The Devil's Advocat on Color Correction" at http://www.graphics.com/modules.php?name=Sections&sop=viewarticle&artid=45 or post their experience with color correction tools.

Please use the "Post Reply" button to post your message.

Guest

Postby Guest » Tue Mar 04, 2003 11:43 pm

Harold,
I read your article very well. However as a PI ( PhotoImpact) user, I take issue with your color adjustment examples you said you did with PI on your two photos.
When I adjusted both your original photos in my PI, in a few short clicks I got results that far surpassed what you got using PI.

Can you explain this?

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Postby HaraldHeim » Wed Mar 05, 2003 12:34 am

Please send me a private email with your corrected images and a description of how you corrected them in PI. I will investigate it. Maybe you have more experience with PI than I and are able to produce a bit better results with it.

The point in my article was to do these corrections from a less experienced user's point of view. Of course, pros might be able to achieve better results, especially if they invest more time or use their extensive knowledge of a tool. However, the majority of people wants to correct their photos as quickly as possible and without investing much time on gathering experiences with a tool.

So I propagate that color correction tools should be usable without special knowledge and should enable beginners to achieve almost as good results as pros.

Jan Esmann

Harrys PowerRetouche examples are far out. Look here.

Postby Jan Esmann » Wed Mar 05, 2003 10:45 pm

Please look here to see what Powerretouche does in a jiffy.
Harrys "examples" of what PowerRetouche does are also included. They are so far out, it seems like a odd deliberate misuse for the sake of denigration.

http://powerretouche.com/WBC/PR_WBC.htm

Jan

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Postby HaraldHeim » Thu Mar 06, 2003 8:24 pm

I had this discussion with Jan on a seperate mailing list, but as he posts this message here, too, I'll have to post my reply again here:

---------------------------------------------------------------------------------
Here are some hard figures that emphasize my point:

Original Photos:

Kitchen Image: Cast Value of 88
Party Image: Cast Value of 95

Jan with PowerTouche:

Kitchen Image: Cast Value of 12 -> 13% of the cast is still remaining
Party Image: Cast Value of 38 -> 40 % of the cast is still remaining

Harry with PowerTouche:

Kitchen Image: Cast Value of 10 -> 11% of the cast is still remaining
Party Image: Cast Value of 16 -> 17% of the cast is still remaining

Harry with ColorWasher:

Kitchen Image: Cast Value of 1 -> 1% of the cast is still remaining
Party Image: Cast Value of 1 -> 1% of the cast is still remaining


Small explanation about the cast values: They are the added values of the absolute differences between the green and red channel and the green and blue channel. The differences are calculated from the average color that was measured from a white area in the image. So higher values mean a stronger color cast. Of course these values aren't absolutely precise, but a good measure. It isn't the only value that could be calculated, but it is one of the most significant ones.

So Jan and I seem to have achieved a similar good result with PowerRetouche on the Kitchen Image. However, Jan's correction of the Party image is much worse. If you compare the results that ColorWasher achieved on both images, you can see that it was more than 10 times more effective than my Powertouche correction. And I guess I needed 10 times less time to do the correction. In ColorWasher I just needed to hit the Auto1 button to get this result and in Powertouche I needed to fiddle with the sliders at least a minute to get that result.

If I would have only wanted to promote my filter, I could have just written
an article that only deals with it and doesn't mention any other tools. As
it is now, all readers of the article can evaluate my experiences by testing
the tools themselves and even come to different conclusions if they have
different preferences about correcting their photos. Secondly, if you read
carefully, you will see that I point out several positive things about other
tools. My reviews of iCorrect and PSP's Auto Color Balance are in essence
quite positive. Thirdly, I didn't hesitate to criticize my own product.
Additionally, I mentioned a lot of constructive points that can give the
developers of these products incentives to enhance their products. If I
would only be interested to depreciate other products, I could have easily
done that without adding more or less implicit advices on how to improve
them.

Does anyone else want to accuse me of depreciating other products?

Of course I can do the same calculations as above for all tools to give my statements a more scientific touch. (Actually I did that when testing the tools, but not that extensively.) Then I can add the values to the article and tell everyone how they can replicate my values and see that they aren't faked. Would that make you happier? I guess it would probably mean that I have to comment on some of the tools even worse than I already did. Anyway, I don't want to write a scientific thesis about this topic... just to give some people something to to think about.

I just wrote an article and reviewed some products. I did that with the best knowledge that I had and didn't try to fake any results. If someone doesn't believe me, he can calculate some cast values himself and see if he can prove me wrong.

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Postby HaraldHeim » Fri Mar 07, 2003 11:16 am

Helen, who wrote above that she managed to produce better results than I with PhotoImpact, just sent me her corrections and description about how she did them.

Her examples were adjusted manually while I used the Color Balance tool of PhotoImpact which is more reliable if you know how to use it correctly.

Her correction had a strong red color cast. The correction I have done with PI also had a red cast, but not such a strong one. So her examples only emphasizes my findings about PI and proved again that some tools seduce users to worsen corrections as they don't give them any clue of what is a good correction or don't lead them to a good correction.

Anyway, thanks, Helen, for your time. I hope my comments will help you to improve your color correction abilities and made you aware of some facts.

I don't mind if someone else sends me examples of corrections he did and thinks are superior. But please investigate them closely before you claim that they are better than my own corrections. I invested quite some time when doing the corrections with the 12 other tools, so please invest that time, too.

Guest

Postby Guest » Fri Mar 07, 2003 9:23 pm

Harry, in all do respect, the examples of mine you saw were what a 'newbie' PI person would go to first to correct your photo since the controls are up front. My point is that even a simple-minded person can do simple adjustments in PI and produce an improved image.

Whether the cast of of the photo is on the reddish side or whatever, it still is *much* better than what you did in your own PI that we saw.

I am in the midst of packing up and moving over 4000 miles in a few short days, but will take this up once again when I have settled in my new home.

If anyone would like to email me, feel free to do so at: helenc@helensplace.com

HaraldHeim
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Postby HaraldHeim » Sat Mar 08, 2003 9:43 am

I don't know what you understand as "better", Helen, but my understanding of "better" is that the colors should be as close as possible to the original scene. That means that white areas should be white and not redish and skin and hair should look natural.

If there had been a red disco light in the original scene of the Party image, then your correction would be appropriate. But I can't find any signs in the image that indicate a red disco light.

I'd be happy to provide more prove of my position. Just let me know when you have time.

Ed Portal

color

Postby Ed Portal » Sun Apr 13, 2003 8:07 pm

Read with interest your article re color correction. I've tried Auto Eye and found it to be useless. The auto-color filter in Photoshop, as tweaked according to Scott Kelby's instructions in his new book on Digital Photography, is far better. I also didn't like Color Mechanic, but I do use iCorrect with almost every photo. First I tweak the photo myself, then i run iCorrect and its brightness and contrast commands. If I add too much, I can always fade back some.

Anyway, it was nice to read that someone else found AutoEye to be not up to snuff.

thanks
EP
http://www.e-portals.org/links/photos


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