Blue Sky - Gernot Hoffmann

"reprints" of selected articles from Usenet and other forums
-default
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Postby -default » Thu Jul 31, 2008 9:30 pm

An interesting discussion of blue sky by Gernot Hoffmann

http://www.fho-emden.de/~hoffmann/skyblue14072008.pdf

derekfountain
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Postby derekfountain » Fri Aug 01, 2008 7:02 am


An interesting discussion of blue sky by Gernot Hoffmann

http://www.fho-emden.de/~hoffmann/skyblue14072008.pdf


That's an excellent piece of work. I'm currently post processing a batch of photos I took at a recent airshow. In typical UK summer fashion, the sky was clear blue one minute and overcast cloudy the next, with periods of broken cloud in between. Cloud is quite easy to work with in CM - texture comes with a steepening of the lightness curve in the right place. Blue skies are a lot harder, looking just plain wrong if they're not absolutely right. Looks like I have my weekend's homework set. :)

mikemeister_admin
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Postby mikemeister_admin » Fri Aug 01, 2008 9:09 am

Yes, I found it interesting, but I'm confused over a number of little points.

a) I dont use the S/H tool, but if my eyes do not decieve me, it makes halos all over the place - is this correct?
b) In example 2, when he starts using the BlendIF sliders to limit the change to just the sky, he changes both the underlying layer as well as the top one.  As far as I can see, it just needs the Yellow lowering to around 116.  What am I missing?

Of course we are lucky using CM in that we can pin a sky to get realistic results!

Bearing the above in mind, the attached photo has an almost exact Brodie sky match in the top left and a very noticeable decrease in saturation towards the horizon (as pointed out my Mike).

So would you like to have a bash at improving this image?  (I had thought of posting it as an example for the current course, because we play with 'bad' images, but not often with moderately normal ones).


mikemeister_admin
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Postby mikemeister_admin » Fri Aug 01, 2008 3:31 pm

My take on it.GregM

-default
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Postby -default » Fri Aug 01, 2008 6:43 pm

Re Shadows and Highlights - yes, it will do halos at the drop of a hat.  It is best used for more subtle changes, rather than to make a sky dramatically darker.

That pic makes me homesick for Hawaii, and I don't even live there...

Nice version, BTW, GregM.

mikemeister_admin
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Postby mikemeister_admin » Fri Aug 01, 2008 6:57 pm

'tis actually New Zealand - South Island

mikemeister_admin
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Postby mikemeister_admin » Fri Aug 01, 2008 9:46 pm

Mike and Zog, I have to confess I cheated on this one and used Nikon's Capture NX.I put  control points in the sky corners and nudged the hue slider.I was using NX but thinking in CM.GregM

-default
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Postby -default » Fri Aug 01, 2008 11:43 pm

Well, I guess I'm homesick for New Zealand then - depending how warm it is there and what the seafood is like.

GregM - you could have fooled me, LOL.


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