Unwanted color shift when adjusting the curve

[Phil518]

Hi:

When I adjust the curve, often it affects the color too. For example, if I push up the curve, the color shifts toward red/orange. It is really hard for me to restore its original color, by adding more adjustment layers, or by adjusting the curve by R/G/B individually.

So what would be a better way to to darken/lighten part of the image, (either by dodge/burn or using curve), while keep the color intact?

Thanks for the help.

Newbie Phil

 

[Eggy]

Depending on the image you could select that particular color(s) and place them on their own layer before applying a curves adjustment layer on the original layer.

On the other hand, since an adjustment layer comes with a layer mask, brush away the parts not in need for a color change.

 

[Phil518]

Hi Eggy:

Thanks for the reply.

I am trying to understand you correctly.

Let's say I am trying to darken part of the forehead of a portrait.

I believe you are suggesting to make a selection of the forehead first (base on its color) and place this selected portion on it own layer.

After that, use the curve tool to darken the target area of the original layer.

Then I will blend the two layers with the "color blend mode", which would apply the original color to the darkened forehead. Mission accomplished.

I'll give it a try and thank ou for the help.

Phil

 

[Eggy]

In a portrait you should do it the second way, add an adjustment layer curves, and apply it.
Then activate the layer mask that comes with the adjustment layer.
With a soft brush and the backgroundcolor set at black, the brush strenght at 20 % brush gently away the part not needing a curves shift.
Alway do it in several runs so you have control over the amount of brush work.

It is always a good idea to turn the image into a smart object before starting to work on it...

 

[thebestcpu]

Hi Phil
If you like the colors without the tone adjustments and only want to adjust the tone with the Curves Adjustment Layer, just change the blend mode of the Curves Adjustment Layer to "Luminosity".

That blend will preserve the color of the lower level while using the curves to only change the luminosity.

You can get partial color area selectivity by using the R or G or B curve adjustments yet if you need more selectaibility then that, you can use other PS tools and/or masks.

Thought this suggestion might be worth trying and hope it is useful

John Wheeler

 

[Phil518]

Thank you very much, Eggy and John.

I tried both methods and both helped a lot. The results from both methods were very close too.

I played around with the luminosity mode and color mode and found out these:

Using curve in luminosity mode won't change the Hue, but would affect the Saturation quite a bit, besides the change in Brightness.

Adding original picture in color blend mode will restore the Hue, but not the Saturation.

Are my observations correct?

To restore the original saturation, I had to add a Hue/saturation layer on top. Is this how you guys would do it?

Thanks!

Phil

 

[thebestcpu]

Hi Phil

I think to help further it would be best for you to post a specific image example as the approach taken will "just depend" so trying to give a recommendation without a picture would at least for me be flying blind.

I would like to point out that we would also need to be on the same page in describing the effect you want to achieve. You mention wanting to change the image with dodging and burning while keeping the same color. It turns out that PS is not is not consistently using the same color model internally.

Turns out that the Hue Saturation and Brightness in the Color Picker vs the Hue, Saturation, and Luminosity are not the same thing. The Hue between those two models are the same yet the Brightness and Luminosity are totally different as well as the Saturation between the two is also totally different.

Given that PS has these differences only make it harder to be on the same page for the visual effect you want to achieve.

I could provide more details on these differnces in PS yet getting to the answer you desire would be faster working with the image in question or a similar example to work with.

Just a suggestion

John Wheeler