Altering hue of a gradient without brightening blacks

[galneon]

I'm currently working on altering a Windows 7 theme that utlizes an accent color similar but not precisely like what I've long been accustomed to.  I have a lot of files I'll have to alter, but I'm willing to take the time if I can manage to do this in a uniform way.

 

Many of the files I'm working with start with a peak color of RGB 0, 144, 187 and then transition to black in one direction, or sometimes transition from color in the middle to black on both sides of it.  Basically, the gradient goes 0, 0, 0 -> 0, 144, 187 [and sometimes -> 0, 0 0].

 

In order to convert the peak to my color, I use the color balance tool with values of 0, 72, 87.  The peak value becomes 0, 173, 238, which is precisely what I want (yes, this is the accent color of the popular DeepDark browser themes).  As you can expect, though, the peripheral blacks are also colorized and lightened.  Because of the gradual fade to black, I'm hesitant to pick a specific point to exempt from the color balance conversion.  Because of varying lengths of the skin elements, I think it's probably close to impossible to always select the proper cut-off point when color-balancing all of these files, so I'd like a conversion method that takes this per-file judgment call out of my neophyte hands.

 

Is there another way I can select the whole gradient for conversion without slaughtering the black end of the gradient?

 

I'm not exactly a graphic artist, so my explanation may be difficult to follow.  Hopefully my examples will help:

 

This is the skin element before I alter the color balance.

 

This is after.  The blue in the middle is correct, but blacks are lost towards the upper and lower margins.  This isn't disasterous, but brightens the theme enough that the final product will look more colorful than dark.

 

And here's one of the many elements that I can't begin to correct with this method.  There must be another way.

 

Thanks for reading and I hope it all makes sense.  Apologies for the tiny images--happy zooming.

[galneon]

Is this a difficult thing to do, or have I explained it poorly?

[Red ochre]

Sorry for the late reply galneon! - it's difficult to explain because there are many different ways to do it. (assuming I understand what you are trying to do! - the screenshots are a bit unclear?  )

Possible ways:
1. Use the brightness/contrast adjustment
2. Use the 'Curves' adjustment - (harder but more control).
3. Use the built in gradient tool on the selection after setting primary and secondary colors to your new colour and black.
4  Use the 'Curves+' plugin
5. Use one of the gradient plugins - I have one called 'Gradients Galore' that works within selections.

Try suggestion 2 and see how you get on - if you have trouble - do report back!
Press the F1 key when Pdn is open and it will take you to the documentation. Here's a direct link.

http://www.getpaint.net/doc/latest/Curves.html

Good luck!