# Advanced colour saturation (Photoshop)



## carsey (Aug 19, 2006)

I had a bit play in PS with colors. Probably looks totally unrealistic, but they were just basic images.

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## DonaldG (Aug 23, 2007)

*Re: HDR Tone-mapping*

OK Carsey
If you want to try an advanced colour saturation technique try this:


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Also see the last image in this posing.

You need photoshop...

1) Put the image on screen
2) Make a duplicate layer of image
3) Select Image-->Mode-->Lab Color (at the pop-up, click: *do not* flatten layer)
4) Ctrl+M to bring up the curves control.
5) Drop down the 'Channel' selector and select channel 'a'










6) adjust the straight line into a curve by dragging point 'x' to the new position, about 1/3 of the way in 
7) do the same with point 'y'. 










Do not click ok yet. Ignore any colours you see your image go at the moment. 

8) Once you have set the curve for channel 'a', do the same for channel 'b'. Do not adjust the 'Lightness' channel.

Still ignore the colours that the image has gone - we ain't finished yet...

9) Select Image-->Mode-->RGB Color (At the pop-up, click *'Do Not *flatten' again)

Almost there....

10) In the Layers Pallet, select the 'blend' drop down and select 'color'









11) Flatten the image and save.

This technique can be applied to an image several times until the desired saturation is achieved.

If you really want to get snazzy with this, you can set up and 'Record and Action' and have the whole process available at one click of the mouse!










The image below has had the action applied 4 times - took all of 3 seconds to apply!


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## carsey (Aug 19, 2006)

Thanks Donald

Had a bit play with your method. Came out awesome.!

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## DonaldG (Aug 23, 2007)

Glad you like that method. The standard method in Photoshop is using the Image-->Adjustments-->Hue/Saturation (Ctrl+U)

The problem I have found with that method is that it is easy to overdo it, get the wrong results and introduce colour noise.

One way of taming the standard method is to increase saturation by a small amount, say +5 and hit 'Enter'

Then hold Ctrl and Alt down and hit U & Enter several times, then release Ctrl & Alt.

What the Ctrl+Alt+U does is to apply again the last amount of saturation applied previously. By doing it several times, you are adding +8 to the original, then +5 to the one before, then +5 again, building up the saturation incrementally. However you will notice that after 3 or 4 saturations, it will look over cooked. So you will then need to look at the history and go back one or two steps until it looks about right.

Again, you can set up an 'Action' so that it can be easily applied by a click of the mouse.


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## Shane84 (Jun 15, 2009)

How about a mention of the good old Channel Mixer?

If you want a really advanced way to boost saturation, try this:

Create a new Adjustment Layer of the Channel Mixer type.

Go to the Red Channel and drag the Red slider up until the reds in your image look good. Note the difference that you've applied to the red slider, subtract 100 and half it. Apply that number as a negative adjustment to the Green and Blue sliders.

e.g. Red Channel: +150R -25B -25G

Repeat for the Blue Channel if desired.

Repeat for the Green Channel if desired.

Voila!

Applying the same amount of adjustment to each colour channel will give an even saturation boost across the image. Applying more or less adjustment allows you to selectively boost different colours. By applying the adjustments in reverse for each channel you can even desaturate some colours whilst boosting saturation of others.

Add masks and you can selectively boost the saturation of some reds (for example) and not others.

This is the best way to alter saturation IMHO and is without a doubt the most versatile way. If you do a side by side comparason, you'll see that this method allows you to boost saturation MUCH further without clipping / posterisation / loss of colour depth than the Hue Saturation Lightness method that we all thought was great when we first tried Photoshop :smile:

One Caveat: The reason that your hues / white balance survive this process unharmed is because we're always applying a balanced degree of adjustment. That is: the sum of all positive adjustments equals the sum of all negative adjustments for each channel. Break this rule and only you can be responsible for the trippy results you may get :grin:


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## DonaldG (Aug 23, 2007)

That is a nice one Shane. Thanks for coming up with that one. I have never done saturation with channels. I gave your method a try - I may not be using my method again for a while!

I have set up a Photoshop 'Action' to apply +110 -5 -5 to the appropriate channels/colours. That way I can incrementally apply even saturation to the photo or masked area, as appropriate.

It also proves the usefulness of PS Actions!

It bears out what I often say; "There is usually more that one way of doing a task in computing." I then add, "... the correct way, is the way you are most comfortable with!"

Keep 'em coming Shane... :wave:


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## Shane84 (Jun 15, 2009)

No problem Donald :smile:

I love this technique and use it a lot. You can pretty easily attain results that are strikingly similar to the Velvia of the good/bad old days by doing this and throwing in a bit of basic curve work. Although obviously it's an infinitely tweakable and locally selective Velvia and you can't say no to that :grin:

The only problem is that, just like Velvia, you have to be careful when using this technique on photos with people in them. Skin tones don't like being boosted too much. Masks will be your saving grace if you ever need to do that though.

It makes me chuckle when people say that digital can't get you the same results as film. It can if you put as much time into developing your RAWs as folk spend developing negatives! And with digital, there are so many more possibilities. Maybe we should let the old timers in on the secret one day!

I absolutely agree that there is always more than one way to do everything, especially in the infinite bladed swiss army knife that is Photoshop :grin:


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