Lee Varis’ 10-Channel Workflow – Part-3

Lee Varis’ 10-Channel Workflow – Part-3

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Picking up where we left off in part-2…

Color Enhanced
Latest color enhanced version.

Now for the really fun stuff… make a new empty layer at the top of the layer stack. Then select Image-> Apply Image… from the menu bar at the top…

Apply Image
Apply Image…

We are going to grab a copy of the b channel from the Lab document and put it into that empty layer. Set up the resulting dialog as shown…

Apply Image Dialog
The ApplyImage dialog – make sure the Source is the Lab document and the channel is set to “b”
B Channel Layer
The grayscale “b” channel is now in a layer onto of everything else!

The grayscale “b” channel has a unique tonal rendering that makes it especially well suited to applying it in Overlay blend mode…

Overlay Blend Mode
Change the layer blend mode to Overlay…
Final Version
The final version – compare with the Raw adjusted version…

This final Overlay blend darkens the sky and lightens the foreground even more! This dramatic improvement is not possible with any other combination of adjustments, and it all happens through blending of the different channels into the color image. Compare with the original raw adjusted version below:

Adjusted Raw
The final version is lighter in the red rocks and darker in the blue sky, as well as brighter greens, in a way that is impossible to achieve with any other method.

At this point, we are done—I end up with a final Curve to set the white point & black point for the image, and call it a day.

I would be remiss if I didn’t point out one possible issue with regards to channel blending the red channel in RGB, with very saturated blue skies, using sRGB. Most natural looking photographic images work very well in sRGB, and gain no benefit from being in a larger gamut colorspace— this would include images with blue sky. However, the channel structure differences between ProPhoto RGB and sRGB are significant, and in some rare instances, ProPhoto RGB can mitigate tone compression problems with the 10-Channel Workflow blends. In our example image, looking at a detail of the sky – in color, no difference between sRGB and ProPhoto RGB…

Full Color
Full color looks the same in both color spaces.

In ProPhoto the red channel looks like this…

ProPhoto Red Channel
ProPhoto Red Channel…

In sRGB the red channel looks like this…

sRGB Red channel
sRGB Red channel…

There is a lot more contrast in the red channel here in sRGB and this is why it can be more powerfully dramatic, and somewhat problematic for channel blends that rely on the red channel, as in that first Channel Mixer luminosity move we used. ProPhoto RGB has a smoother red channel, and that can have some advantage in a channel blend maneuver. This advantage is not always obvious for blue sky images, and not advantageous at all for most other subjects. Portraits have a lighter red channel and so they don’t suffer from the red channel contrast defect in sRGB, and subjects with strong green content are also fine in sRGB, so most of the time sRGB is fine for this channel blending strategy. It is worth checking to see if you notice any posterizing around cloud edges in saturated blue skies after doing the red channel blend in sRGB—if so, try processing the image into ProPhoto RGB and doing your red channel blends there. Sky darkening effects won’t be as pronounced, but you are less likely to add posterization artifacts with particularly saturated blue skies.

Special Note:

I have a new online course: The 10-Channel Workflow – a comprehensive guide with 9 step-by-step projects with detailed video instruction, including downloadable work files for only $40. Click to learn how to enroll now.

I have a number of other color correction blog posts on my website that may also interest you –

Lee Varis

Owner at Varis PhotoMediaLee Varis is a Boston based photo-illustrator whose career in commercial photography spans four decades. His work includes movie posters (Star Trek,) albums, CDs, and magazines (Nat Geo, Fortune, PDN.) Lee is the author of the best selling Photoshop book “Skin: The Complete Guide to Digitally Lighting, Photographing and Retouching Faces and Bodies."

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Categories: Tutorials Tags: 10-channel workflow color grayscale channels LAB layers Lee Varis luminosity blending Photoshop RGB step-by-step tutorial

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