Elusive yellow Options

[MickinPlymouthUK]

Hi,
Sometimes I come across old colour photos while surfing (World War Two is my thing) which are often too dull or too blue or whatever, but I can jazz them up pretty good by juggling various Irfanview enhancement sliders and buttons and make them presentable for posting in military forums.
The Red/ Green/ Blue sliders in particular are essential, but I can't figger out how to introduce a bit of yellow into pics where needed to improve the overall balance.
If only yellow had a slider I'd be ecstatic, but there are only the red/blue/green sliders, so how do I conjure up yellow?
I'm Win XP Home
Thanks

[Vaerli]

See if there's a way to do it in CMYK - cyan, magenta, yellow... and... something that starts with K. I don't use IRfanview, so I can't really walk you through it. GIMP could fix it up through curves probably.

You should be able to adjust it by using a combination of two sliders I would believe.

[tg1911]

You'll have to play with it to get the shade you want.
Increase the Red, and Green.
Decrease the Blue.

You could start off with one of these:

Bright yellow: Red-254, Green-250, Blue-67
Subdued yellow: Red-255, Green-252, Blue-130

You don't have to use the sliders.
You can type in the values, manually.

If you're looking for a particular shade, here's the way to find the values.
Open Irfanview.
In the Tool Bar, click Image and select Create New (empty) image...
This will open the Create New Image dialog box.
Click the Background color button.
This will open the Color dialog box.
Under Basic colors:, click one of the Yellow squares.
On the right, click and hold the arrow, and drag it up or down, until you get the desired shade.
Once you have the shade you want, write down the numbers next to Red, Green, and Blue.
Close out everything, and open the image you want to adjust.
Use the numbers you copied, to fill in the values next to the sliders.