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Grey skies to blue

Posted: June 13th, 2010, 9:47 pm
by MikeG
A few days ago a friend who lives east of London, England, sent me a photo that he had taken of a Red Arrows fly past 'for' his wife's birthday. (Where 'for' means 'on').
sized_RedArrows.JPG
sized_RedArrows.JPG (47.88 KiB) Viewed 7617 times
Obviously this is a simple image and it's easy to mask the Red Arrows as there is nothing else remotely red in the image.
What absolutely delighted me, however, was the ease of transforming the grey skies into blue ones in one step by using the Color Remap transform. So, in 10 minutes or so I was able to send my friend the version show below
Mike.

Re: Grey skies to blue

Posted: June 14th, 2010, 8:08 am
by den
MikeG....

Try using a Remap unchanged color pair to preserve the whiter clouds tone/color while with a second color pair, change the brightness/saturation of the darker clouds... you may be able to preserve more of the interesting highlight cloud detail...

Just a thought....

Re: Grey skies to blue

Posted: June 14th, 2010, 12:16 pm
by cliff
My preference would be to use the Color Curves Transform. I set the V curve to (0,0), (90,100), (100,100), and the S curve to (0,0), (55,100), (100,100). No mask was necessary.

It sure would be nice to have a "Challenge" or "Gallery" forum. So we could see how different users of PWP would edit images.

Cliff

Re: Grey skies to blue

Posted: June 14th, 2010, 12:25 pm
by cliff
Looking at the image on the board, I should have moved the middle values higher as well.

Re: Grey skies to blue

Posted: June 14th, 2010, 6:42 pm
by MikeG
Cliff,

I do like your last image. Perhaps part way between yours and mine would 'ideal' in my eyes.
I'm a bit pushed today but I'll look forward to experimenting tomorrow.
Almost any blue sky variant is better (in my opinion) that the depressing grey of the original.

Mike.

Re: Grey skies to blue

Posted: June 16th, 2010, 8:42 pm
by MikeG
Cliff,

Thanks very much for your suggestions. I had no idea that good results could be obtained so easily with the Color Curves transorm.
But to refer to your suggestions in order.
1. A same colour pair in Color Remap. I tried this and did get a more interesting result, as you had predicted.
RedArrows-CR2.jpg
RedArrows-CR2.jpg (34.44 KiB) Viewed 7318 times
2. Color Curves transform. As I noted above, I was very surprised that this had such a big effect - I have to admit the the Color Curves are at the top of my - need-to-understand-better list. However, I couldn't find a way (short of using another trransform which I didn't attempt) to sufficiently reduce what I can only describe as 'white noise' which I hope is visible below is this 1:1 crop.
RedArrows-cf no mask-1to1.jpg
RedArrows-cf no mask-1to1.jpg (46.15 KiB) Viewed 7316 times
For comparison, below is a similar crop from my Color Remap (with mask) image.
RedArrows-CR2-1to1.JPG
RedArrows-CR2-1to1.JPG (45.91 KiB) Viewed 7323 times
Any futher tips would be greatly appreciated.

BTW, a full size version of the original after cropping and enhancement of the planes only ie original grey skies, is available here:
http://picasaweb.google.com.au/Michael. ... 3487067938

Thanks, Mike.

Re: Grey skies to blue

Posted: June 17th, 2010, 4:42 pm
by MikeG
Should have thought of this before - have now posted the 'Red Arrows' mask, available on the link given above.

Mike.

Re: Grey skies to blue

Posted: June 17th, 2010, 6:44 pm
by den
Of course, since we are altering reality, a blended sky substitution could be done:
Composite-sized_RedArrows-1-1-1-1.jpg
Composite-sized_RedArrows-1-1-1-1.jpg (25.96 KiB) Viewed 7229 times
The ease with which this can be done even for digital movies as well as a single frame makes one wonder why the US WhiteHouse had 747's flying low around NY City taking AirForce One footage with NYC backgrounds.... scaring the City with a reprise of September 11th!!!

Re: Grey skies to blue

Posted: June 18th, 2010, 12:51 pm
by cliff
Hi Mike,

I'm still new to PWP, but the Color Curves transform has become a very important tool for me. It gives extreme control over the HSV channels. Everyone uses the values curve, but I wonder how many people use the saturation and hue curves. For example, after masking a face you can use this tool to map all the pixels into exactly the hue and saturation you want.

The technique I suggested does magnify small problems and tends to show the "white noise" you mentioned. Right now I'm not sure how to prevent that.

BTW it was den who made the excellent suggestion of using a second pair with the Color Remap tool.

Re: Grey skies to blue

Posted: June 18th, 2010, 4:18 pm
by cliff
I wish I could edit the previous post. After working with the Color Curves transform for awhile, I now think it's easier to adjust Hue and possibly Saturation using the Color Correction transform.