I was wondering where to put this on the forum, but since i'm going to
link it to the gradation curves filter,it made sense to put it here..
IF YOU ARE A BEGINNER TO VIRTUALDUB LOOK HERE FIRST....
http://forums.virtualdub.org/index.php?act=ST&f=4&t=14396&hl=
HOW THIS EXPLAINATION WORKS
I've used the smartcurve photoshop plugin but the methods
apply to practically any programs that use curves for colour
correction.
I've also tried to keep this as simple as possible, I'm
assuming you know nada, so i'm not even going to
go near the histogram to start complicating things.
WHAT IS SMARTCURVE ?
Smartcurve is a photoshop filter plugin which you can download here.
http://www.free.pages.at/easyfilter/curves.html
You need version 2.0 from the above site.This is the one with more
colourspaces.
I personally think this is the BEST free curves editor out there
and have used it in photoshop instead of the native photoshop curves editor.
INSTALL SMARTCURVE
Download the file, extract the 8bf file, and put it in your photoshop plugins
folder.
"BUT I DON'T HAVE PHOTOSHOP!"
Well there are many free and commercial programs
that can use photoshop plugins without needing photoshop
and give exactly the same results.
Here is a list.
http://www.thepluginsite.com/resources/freeplugintools.htm
Pick one.Install it. I recommend Paintshop pro.There is a trial version:-
http://www.corel.com/servlet/Satellite/us/en/Product/1185293041793
Or maybe you already have one on the list or photoshop.
Extract smartcurve file and put it in the plugins folder.
start up the program and access the plugin!
SMARTCURVE LAYOUT
Most curves editors have a variation of this layout,
Colour spaces....
If you open a different curves program you'll find
it's pretty similar and YOU WON'T BE LOST.
READING THE CURVE LINE DISPLAY.ESSENTIAL!
This is essential! If You don't get this you can forget
reading the rest.Once you understand this everything falls into place.
Pay attention to the images below. It's spelled out blatantly:
In the images above, the line below is the range -from dark to light in your image.
The line on the side, vertically is the range-dark to light of what your image could be.
ONE WAY OF EXPLAINING IT EASILY:-
.1 You look at your image.Let's say you see a very black area.
You want it lighter!
.2 Goto the bottom range-which is your image NOW Find the darkest area
(the extreme left-black) on the range.Look up where the diagonal line is, click
a point on the line.
.3 Then look to the left range (what your image could be) -how light
do you want it??
.4 If you move it to the top of the left range(see that's the lightest-white)
If you move it all the way up it will become that light!
The above is the basis for ALL CURVES colour editing.
Re-read again and again the above till you understand it.
You may have noticed you weren't as accurate as you wanted in the above
which is where you need knowledge in...
[b]ISOLATING A SPECIFIC AREA OF AN IMAGES TONAL RANGE.
The big advantage of colour curves correction is you can be very surgical,
and as subtle or as brutal as you want.
But to be that surgical, we have to ISOLATE the tonal range we want
by adding points around it.
basically you add points before and after the actual point you want to edit on the line.
The closer the points together, the more specific the tonal range you want.
The further apart they are, the bigger tonal range you will affect.
the biggest tonal range is of course the points at the opposite ends of the line.
ADJUSTING A SPECIFIC AREA OF AN IMAGES TONAL RANGE.
As an example, let's adjust something we can clearly see in the image, the DARKEST
parts of the image-THE BLACKS. This is shown in the animated gif below:
USING THE COLOUR CHANNELS.
Sometimes you only want to change very specific colour elements
in an image, say the bright blue skies in a picture. Or Add colour
to things like shadows.
You don't just have the ability to adjust an images tonal
range with surgical precision with curves, but also specific colour channels.
As shown in the animated gif below.
SAVING YOUR CURVE AS A FILE FOR LATER USE.
It might take you a while to get that look you wanted with the curves,
you don't want to be spending the same amount of time again and again
doing the same thing if you want to apply the same effect to other images.
Well you can save the curves file as an .AMP file and apply
the curves correction stored in it to any image file you want.
Or import that into the gradation filter in virtualdub and apply the
same colour correction to video.
The animated gif below explains it best.It's very easy...
IS THAT IT?
well it is that simple.But what makes this way of colour
correcting better than others is the range from light to dark can be HUGE.
You can not just do the blacks and light, but shadows, cotton clouds while leaving
bright whites alone and using colour channels gives you thousands more options:
This is how all this was done....
http://neuron2.net/board/viewtopic.php?p=8043&sid=babf2650d8b1d899f8029f8b150e39dc
Heri Mkocha
