More blue in the sky

[Abitconfused]

I started using Curves (Photoshop CC) to adjust the Blue Chanel and then the same curve to adjust RGB values to obtain a bluer sky.



Result:



I also add blue Chanel saturation.

There must be a better way to get a blue sky without over-saturating all colors and/or causing color shifting. But I don't know what that may be...?

[pnodrog]

I tend (not always) to select the blue sky rather than doing global adjusts.

[Brev00]

I also do not like the effect of playing with color curves. I have Elements so shoot over to my plug-ins if I want to adjust specific colors. Perfect Effects 9, Nik Color Efex, and Topaz Clarity all have color channel sliders that work very well in making these subtle adjustments. Remember blue sky is not just blue but a combination of the different colors. I usually start with making sure my white balance and tint are where I want them to be in Adobe Camera Raw and select a picture control that plays nicely with the blues. I find Adobe Standard is the least effective in terms of getting nice blues and Landscape and Vivid overdo it. Camera Standard, Neutral, and Portrait tend to look better to me in terms of blues. This pic looks overexposed with the very white clouds. It is obviously key to get a good exposure but without underexposing (kills the brilliance and adds noise). It is good to expose to the right without clipping. Then you can bring down the exposure to the right shade in post.

[jcuknz]

I think that if you do a careful selection of the sky around the log and tree you should be able to simply use the brightness/contrast tool. I did a rough selection which I will not show you but I do not think you can do much about the lightness which looks like fall off due to polarising filter short of using the darkening brush at low intensity and gradually building the area up.
The rest of your image has not been affected by these actions[ I used the darken brush at 35%]

[Manfred M]

I find using the using the blue and aqua sliders on ACR's Grayscale / HSL tab works best for me and is not quite as brute force as using curves. Make sure you are adjusting just the luminance.



Note - I didn't need to use this technique in this image, the sky was already bordering on being too blue.

[DanK]

I most often do what Manfred does, although via Lightroom rather than ACR in Photoshop (same engine, slightly different interface). However, that is a global adjustment, and as L. Paul points out, sometimes it's better to work just on the area in question so that you don't mess up colors elsewhere in the image.

[Rob Ekins]

There must be a better way to get a blue sky without over-saturating all colors and/or causing color shifting. But I don't know what that may be...?

Ed,
Use a hue saturation layer not curves.
Once you are in H/S click on that hand with the arrows in your first image, that icon will act as an eye dropper and only increase the hue and saturation of the selected colour, in your case blue.

When that selection is made and a new layer is created you can increase/decrease opacity, change blend modes etc.

[NigelD]

I've started to use LAB colour adjustment for saturation after watching video tutorials by Lee Varis on You Tube. That way you can affect just the individual colour rather than everything. I also use the same method as Manfred.

Also, you don't have to do an adjustment on the composite RGB image when performing a curves adjustment, you can select the blue channel only from the drop down menu.

[xpatUSA]

I'm late to the party but members might find the following interesting.

In RawTherapee there is a 3-channel color mixer. It works the same as a 3x3 matrix mathematically. You can take any channel and feed some of it into other channels. Obversely, the contribution of channels can be reduced, similarly to individual curves or levels. So, without further ado:




The Sigma SD14 is quite heavy on greens and, in the sky at right, also a slight tendency to cyan (towards green in color circle hue terms). So, in the mixer, I took out 25 from the green channel and added it to the blue channel. That caused a slight red cast, so I took 10 out of the red channel and added it to the green channel. Could have gone a bit more perhaps. I find that equal amounts of adjustment helps to reduce color unbalance.

This method would be more helpful to those who prefer global adjustment and who do not have the luxury of layers, masks or area editing - like my Adobe-free self (just had to say it . . . .).

As to the color of the grass which might draw comment, the actual scene colors are somewhere betwixt the two images above. A little more playing with the sliders would have fixed that - but I'm just illustrating a method here.