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Transcript for Improved Saturation with LAB -- Part II

Transcript by Ron Bigelow

Photoshop CS4 Used in this Tutorial

In our last video, we started the LAB saturation workflow by converting a copy of our Rainforest image to the LAB color space and moving the black point and white point sliders inward in the a and b channels. However, we have some more work to do.

Let’s go back to Curves. Watch as I move the a and b channel black point and white point sliders inward even more. Okay, some of you are probably thinking, “This image is now ridiculously over saturated. Ron has gone way off the deep end”. However, there is method to my madness. You’ll see.

It is now time to move back to the RGB color space by choosing Image/Mode/RGB Color. We run into a warning. This warning indicates that we have encountered our second limitation of the LAB saturation workflow. We can not move in and out of the LAB color space with layers. However, we do not want to discard the adjustment layer because we will lose all that work that we just did in the LAB color space. So, we will just flatten the image by clicking the Merge button.

What we need to do now is move this image over to our unsaturated image. To do this, we click on the Arrange Documents menu and select Tile All in a Grid. We see three copies of the image. The Rainforest (Hue Sat) image is the original image that was saturated with the Hue/Saturation adjustment. The Rainforest (LAB Sat) image is the original image that has not yet been saturated in any way. Of course, we have the Rainforest (LAB Sat) copy that we saturated in the LAB color space.

Okay, let’s make our move by selecting the Move tool in the Tools panel and dragging the Rainforest (LAB Sat) copy image over to the Rainforest (LAB Sat) image while holding down the Shift Key. Holding down the Shift key ensures that the images are placed directly on top of each other without any shifting of the images.

We no longer need the Rainforest (LAB Sat) copy image, so let’s close it.

We now click on the Arrange Documents menu again and select Consolidate All so that we can better see our image. Let’s rename our LAB saturation layer as LAB.

Now, the image is obviously over saturated. Let’s take care of that. First, we need to change the Blend mode. We can do this by clicking on the Blend Mode pop-up menu. We want to choose the Color blend mode. The Color blend mode passes along the hue and saturation information from our LAB layer, but the luminosity information is not passed along. This will allow us to separately adjust the luminosity, if we so desire, at a later time.

Our next step is to decrease the opacity by dragging the Opacity pop-up slider. I like a setting of around 65%.

Do you understand why we deliberately over saturated the image in the LAB color space? This allows us to later adjust the saturation, once we are back in our original color space, by adjusting the Opacity pop-up slider. This provides you with more flexibility. If you want less saturation, you can just decrease the Opacity. If you want more saturation, you can simply increase the Opacity.

Okay, it is show and tell time again. Here is our image saturated in the more traditional way with the Hue/Saturation adjustment. Here is our image saturated with the LAB saturation workflow. Clearly, this image has a superior saturation. Furthermore, this image shows what I saw when I was taking the image.

I absolutely love this technique. However, like everything else in life, it does have some limitations. Let’s talk about those limitations now.

You have already seen the first two limitations. You should not use this workflow on Smart Objects because changing modes can affect the appearance of Smart Objects and you can not move in and out of the LAB color space with layers.

However, there is one more limitation. The LAB workflow is best used with images that are in a large color space (such as ProPhoto RGB). This issue has to do with the spreading apart of the colors in LAB. If the original image is in a small color space (such as sRGB), we could end up with colors in the LAB color space that do not exist in the original color space. These colors would be out of gamut in the original color space and would have to be rendered back within the original color space when the image was converted back from LAB. This would result in some image degradation.

Well, that is pretty much it for this workflow. I hope that you find this technique as valuable as I do.

Before I sign off, I would like to take this opportunity to let you know that you can download the transcripts for this video series, view several other photography videos, and access over 100 photography articles on my website.