Dan Margulis Applied Color Theory

The Color Boost Action

Superadvanced/PSW 5--The Color Boost Action
Posted by: Dan Margulis
Thu Apr 23, 2009 1:43 pm (PDT)

In this economy, almost all of us are encountering friends or acquaintances who have fallen on hard times. Highly skilled retouchers, as I noted in an earlier post, are not exempt from the bad economy but are not doing all that badly either.

When one of them starts to divest himself of the usual retoucher lament, that he is so busy that he has no life, that he is getting little sleep and his love life is suffering, that he has a feeling that he could make a good living if it wasn't for having to deal with all these unreasonable clients, I have a standard reply. I ask, "Would you rather have the opposite problem?"

When working with color, that question can also arise. When trying to boost color in LAB, many people already deliberately go too far, intending to reduce opacity to taste afterward. I've concluded that a modified version of this is the correct approach. In other words, given the choice, the problem of being too colorful and having to decide how back off is preferable to not being colorful enough and having to force color in somehow.

This is particularly the case when using the picture-postcard workflow. The first step of that workflow merely provides acceptable but not vivid color; the second enhances detail with luminosity moves. After that second step, the color is usually worse than in traditional workflows, so it tends to need a big boost, and LAB is the space of choice to do it.

Accordingly, I now plan that in most cases I will have a super-colorful version that then gets toned down in an agreeable way. I've got a quick Action that I've given to the last few ACT classes, including the superadvanced, and the reviews are very positive.

A copy of this Action can be downloaded here. It works in the English-language version of Photoshop only. We have one that works for the Italian versions of the program here. These Actions have been tested in Photoshop CS3 and CS4 only. --DM

The Action requires an LAB file. There are two curves adjustment layers. The top one is empty, just default curves. It's there in case we want to make some kind of move in the L channel. Since the workflow doesn't necessarily set highlight and shadow early in the process, this L move may be needed, or we may decide to lighten or darken the picture. But by default, this top layer does nothing.

The real pizazz is on the middle, Color Boost, layer. It consists of an extremely steep B curve and an even steeper A, in keeping with my recent post recommending that the A be enhanced more than the B. The default opacity is 75%, which is way too colorful for any but the blandest images.

The no-brainer way to make the color more reasonable is to reduce this color-only layer's opacity to taste. However, there are often better options. We are usually more willing to accept vivid colors in lighter areas as opposed to darker ones. Therefore, it's worth a try to, rather than reduce opacity, load the L channel as a layer mask, thus allowing more of the impact to hit light areas than dark ones. Then, with the mask loaded, the layer opacity can still be adjusted--either up or down.

If the base file is already fairly colorful and the opacity of the Color Boost layer looked best at around 15 or 20% opacity, then it probably won't make any difference whether you mask the boost or not. But the more bland the base layer, the more likely you are to hit one where the mask will have an advantage.

These two methods are enough to make the Action worthwhile, but there's a lot more available for those skilled at editing layer masks. By clicking into the mask curve, we can isolate the tonal range we want to affect, lightening or darkening the mask as necessary. Another powerful tool is to use the A and B channels to augment the mask. Rarely should the A or B be used as a mask itself, but by loading the L first and then applying the A or B in Overlay mode (sometimes inverted) we can emphasize certain colors over others.

Anyhow, this simple Action is a pretty useful gadget--once you get used to the idea that the weird look it imparts when first applied is a better problem to have than the alternative.

Dan Margulis
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Re: Superadvanced/PSW 5--The Color Boost Action
Posted by: "John Bongiovanni"
Mon Apr 27, 2009 7:58 pm (PDT)

Dan Margulis wrote:

The real pizazz is on the middle, Color Boost, layer. It consists of an extremely steep B curve and an even steeper A, in keeping with my recent post recommending that the A be enhanced more than the B.

So how does this affect your Multiply move in the Picture Postcard Workflow? Here the Multiply is doing an Overlay of A and B channels onto each other. The Overlay is the equivalent of a curve on the A and B channels. What that curve looks like, I don't know, but I know that it is the same curve for A and B channels. What you're saying here (and in the earlier post) is that you need a stronger move in the A than the B channels.

Are you suggesting replacing the Multiply move with some kind of curve? Or something else?

John Bongiovanni
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Re: Superadvanced/PSW 5--The Color Boost Action
Posted by: Stephen Marsh
Tue Apr 28, 2009 1:08 am (PDT)

John Bongiovanni wrote:

The Overlay is the equivalent of a curve on the A and B channels. What that curve looks like, I don't know...

I have uploaded an "overlay" blend mode curve screen capture to the files section titled: overlay_curve.gif

photoshopnews.com/2007/09/05/how-to-express-blend-modes-as-curves
photoshopnews.com/stories/downloads/blend_curves.zip

Regards,

Stephen Marsh
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Re: Superadvanced/PSW 5--The Color Boost Action
Posted by: Dan Margulis
Tue Apr 28, 2009 7:49 pm (PDT)

John Bongiovanni writes,

So how does this affect your Multiply move in the Picture Postcard Workflow? Here the Multiply is doing an Overlay of A and B channels onto each other. The Overlay is the equivalent of a curve on the A and B channels. What that curve looks like, I don't know, but I know that it is the same curve for A and B channels. What you're saying here (and in the earlier post) is that you need a stronger move in the A than the B channels.

Are you suggesting replacing the Multiply move with some kind of curve? Or something else?

This is a good question but I'm not sure I have the correct answer. There are several ways of modifying the multiplication to make more use of what I posted. At the moment, what I'm doing is:

1) Multiply as usual, except I am more prone to use the top layer's L channel as the layer mask, rather than the bottom's. Since the top layer has been multiplied its L channel is darker, and the resulting image is lighter. This gives a little more flexibility because the Action has a layer that is reserved for adjusting the L. Also, the lighter image doesn't boost the colors quite as much, allowing the Action's color boost layer a bit more room to maneuver.

2) Apply the Action as usual, but consider the possibility of reducing the opacity of the multiply layer. The Action's color boost layer and the multiply layer both try for the same objective but use different ways to get there and one may be preferable to the other.

This idea is similar to what I am now using for images with tepid color. Before moving from RGB into LAB, on a duplicate layer I apply a master curve that lightens the midtone and darkens the shadow. This layer is set to Color mode. The result is a color boost, but of a different flavor than what's about to happen in LAB.

I keep that layer intact upon moving into LAB, and then apply the Action. In some cases having that extra color boost gives something that the LAB curves don't and in others it's a waste of energy that gets deleted. But I don't mind looking at the choice.

Dan Margulis