Re: [Gimp-user] sky question

2008-11-16 Thread Akkana Peck
Marco Presi writes:
> If you want to artificially change the colors, I think the best way to
> do it, is to do it in a selective manner:
> 
> 1) duplicate the layer of the original photo
> 2) change the color of the duplicate layer by using the color balance
> tool to reach the sky tonality you want (don't pay attention to want
> happens to the rest of the photo)
> 3) apply a layer mask to the modified layer (hiding all the modified
> layer)
> 4) select a brush with proper dimensions and draw with it over the layer
> mask: this will reveal the modified layer. If you draw only over the sky
> region, you will obtain the sky with your colors, while keeping the rest
> of the image with original colors. You can play with different brushes
> and different brush settings (I found the opacity setting very useful)
> and see how to get the best results

If you get tired of drawing manually on the layer mask to keep only
the sky, there are ways of getting GIMP to select the sky for you.
Basically, you use Decompose to split the image into various aspects
(hue/saturation/value, red/green/blue or sometimes others) then
use one or more of those layers to help you make a layer mask.

There used to be a wonderful tutorial on that technique by Jenny Drake,
but unfortunately the site is no longer online. The Internet Archive
has the text of the tutorial but no inline images, but you can
read the text here:
http://web.archive.org/web/20050313031704/http://www.photojenic.co.uk/home-page/gimp-sky-colour.html

And Carol Spears wrote a good tutorial based on it which *does*
have images:
http://carol.gimp.org/gimp2/photography/sky/compose/

If you can forgive a brief commercial note, there will be a couple
of examples of the same technique in the 2nd edition of Beginning
GIMP (expected in late December). Now that I see Jenny's tutorial
is gone, maybe I'll try to find time to put some of it into a web
tutorial ...

-- 
...Akkana
"Beginning GIMP: From Novice to Professional"  http://gimpbook.com
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Re: [Gimp-user] sky question

2008-11-14 Thread Marco Presi
Il giorno ven, 14/11/2008 alle 19.09 -0400, Joel Glanfield ha scritto:
> Hello,
> 
> First time poster here.
> 
> Just curious about how to change sky-colors like you see in a lot of 
> professional photographs. For example, on this site:

as already someone replied, at sunset and sunrise the sky colors are
wonderful. You might achieve nice results also by using a polarizer (if
you can attach it to your camera): it really makes the difference

If you want to artificially change the colors, I think the best way to
do it, is to do it in a selective manner:

1) duplicate the layer of the original photo
2) change the color of the duplicate layer by using the color balance
tool to reach the sky tonality you want (don't pay attention to want
happens to the rest of the photo)
3) apply a layer mask to the modified layer (hiding all the modified
layer)
4) select a brush with proper dimensions and draw with it over the layer
mask: this will reveal the modified layer. If you draw only over the sky
region, you will obtain the sky with your colors, while keeping the rest
of the image with original colors. You can play with different brushes
and different brush settings (I found the opacity setting very useful)
and see how to get the best results

Hope this helps

Marco

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Re: [Gimp-user] sky question

2008-11-14 Thread yahvuu
Joel Glanfield schrieb:
> Just curious about how to change sky-colors like you see in a lot of
> professional photographs.

Hi Joel, just shoot your photos around sunrise/sunset (at the right day).

Ken Rockwell explains:
"Most people never see colors like this because they live indoors,
work in an office, drive to and from work, and live in a house.
These colors happen outdoors in nature. The peak color,
which are the shots I show, only exists for 60 seconds at most,
if it happens at all, any given day"
http://www.kenrockwell.com/tech/color.htm

For changing colors using gimp, you can play with the various commands
in the "color" section, e.g. Hue-Saturation

greetings,
peter


related:
http://www.kenrockwell.com/tech/timing.htm
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[Gimp-user] sky question

2008-11-14 Thread Joel Glanfield
Hello,

First time poster here.

Just curious about how to change sky-colors like you see in a lot of 
professional photographs. For example, on this site:

http://www.novascotiaphotos.com/

...the banner at the top has purple sky, and there are several photos in 
the gallery with different sky-colors. What's the best way to go about 
doing this using the GIMP? I've been doing some googling, but I'm 
probably using incorrect search terms since I haven't really found 
anything helpful (yet).

Any replies are appreciated!

Regards,
Joel
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