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how can i separate colors from light ?

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  #21  
Old 08-10-2011, 11:47 AM
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Re: how can i separate colors from light ?

Quote:
Originally Posted by John Wheeler View Post
This in my mind does not just isolate changes to just areas of color.
Seems you have just misunderstand how the blending modes work.
Think of each pixel as defined by Luminosity (brightness) and Color (Hue + Saturation). (see first attachement)
"Color" blend mode alters the color component of without changing the luminosity (and vice versa).

If you look at your example, when you added the yellow layer and blended it as "color". The color of the gradient thus changed to yellow, but the Luminosity/brightness was not changed (it still went from black/dark to white/light).

There are 4 blending modes that are related here:
  • Luminosity make the layer only affect the luminosity (brightness).
  • Color only affects Color (Hue + Saturation) - not luminosity.
  • Hue only changes the hue - not saturation or luminosity.
  • Saturation only changes the saturation - not the hue or luminosity.

Quote:
Originally Posted by John Wheeler View Post
I hope that is the case because there is a lot of confusion to be cleared up.
In his last post Mantra said clearly that he wanted to work on Color and Luminosity separately. The Color and Luminosity blend modes lets you do this.
If he - as you suggest - wanted to create a mask separating the pixels that have a Color component and those who have "none" (those who are gray), he would be looking at some sort of saturation mask (as others have talked about earlier in the thread). (see 2nd attachement)
Attached Images
File Type: png color.png (75.2 KB, 43 views)
File Type: png color2.png (55.6 KB, 44 views)

Last edited by Chain; 08-10-2011 at 12:00 PM. Reason: Fixed some mistakes and clearified a little.
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  #22  
Old 08-10-2011, 11:59 AM
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John Wheeler John Wheeler is offline
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Re: how can i separate colors from light ?

Hi Chain and thanks

We are on the same page as far as blend modes. What I was responding to was the OPs original question:
Quote:
how can i separate colors from light ?
The Color Blend mode allows non-color areas to be changed as we agree yet not sure that is what the OP wants.
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  #23  
Old 08-10-2011, 12:10 PM
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Re: how can i separate colors from light ?

Quote:
Originally Posted by John Wheeler View Post
The Color Blend mode allows non-color areas to be changed as we agree yet not sure that is what the OP wants.
What do you mean by that? A layer set to Color will affect everything that isn't pure black or white. If you by "non-color" areas mean gray pixels, then yes, those are affect, just like green pixels, or beige pixels...

---

OPs original formulation was a bit open to interpretation as he said he wanted to "separate colors from light ?" and then went on to talking about how he failed to achieve this using masks. He did not know how to achieve what he wanted (or how to unambiguously describe it in English), so the not-so-clear post is understandable. He later said "yes i would like to separate color from the luminosity ,to tweak the colors in the photo without touching the lights".
His latest post is pretty clear to me; he want to adjust the Luminosity and Color separately (in this case, change the colors in the image without making it lighter/darker). This is done using the Color blend mode on the adjustment.
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  #24  
Old 08-10-2011, 06:07 PM
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Re: how can i separate colors from light ?

Quote:
Originally Posted by Chain View Post
His latest post is pretty clear to me; he want to adjust the Luminosity and Color separately (in this case, change the colors in the image without making it lighter/darker). This is done using the Color blend mode on the adjustment.
Hi Chain
If that is what the OP is looking for, I totally agree.
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  #25  
Old 08-11-2011, 08:02 AM
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Re: how can i separate colors from light ?

Quote:
Originally Posted by mantra View Post
yes i would like to separate color from the luminosity ,to tweak the colors in the photo without touching the lights
the blend color is good , but ... does change a little the lights ,according to the histogram
From what I read you've already tried Color mode and it's not good enough for you (reasons why this could be can be found here, though I find this approach overkill for 99% of the images I work with, but it's up to you: http://www.freegamma.com/manuals/Lob...aticity_v2.pdf)
If this is what you want, try the link to Benski's blog that Flashtones posted above, which provides a method of extracting Color with a Channel Mixer adj. layer.
Set the Channel Mixer to "Color" mode, clip a curves adj. layer to it and play around with the individual color channels which should now only affect the color and avoid flaws that could occur when you're just using "Color" mode alone (e.g. desaturation in highlights and shadows).
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  #26  
Old 08-11-2011, 01:56 PM
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John Wheeler John Wheeler is offline
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Re: how can i separate colors from light ?

Hi Mantra
I hope you got your questions answered. If not, I still suggest posting an image with some info on what you are trying to achieve. With the language and terminology translation issues I think an image would speak a thousand words and help forum members more productively help you.

A previous thread from you a few months ago with a lot of the same responders I believe would also have benefited from an image to help describe the issue/problem/topic with which you wanted help (again communication issues):

http://www.retouchpro.com/forums/pho...ate-black.html

I hope you understand this as a respectful suggestion for better and more efficient communication. All of this is IMHO of course.

Best wishes on your project.
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  #27  
Old 09-13-2011, 02:09 AM
adtechniques adtechniques is offline
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Re: how can i separate colors from light ?

A great topic, but it seemed to have too much knowledge for me, it makes me disorderly )
I want to ask about using this method for edit image . Here pictures I've edited.
Edit.jpg
I don't know how to read Hue & satu map. Examples of satu-map of my photos.
Satu.jpg

There are lots of shadows and highlights, but how is "a good" satu-map. I want to adjust to get more uniform saturation but don't know where to start. I do very emotional. I use a white brush to paint over the area which i want to reduce the saturation, but when increase the saturation, I don't know what color must used. In Der_W video's, I saw him use Red with HSB parameters: 0 - 100 to 100 to fill where need to increase the saturation. But why he use that parameters, in other areas, Which color must use? Which parameter?

Another problem is reading color map, usually have an orange or green all the colors. Why two colors are always present when using the color map?
Hue.jpg

I still read the documentation about it but I thought it would be easier to understand if the exchange with everyone.
Thks
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  #28  
Old 09-13-2011, 03:32 AM
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Re: how can i separate colors from light ?

The saturation maps shows black where areas have 0% saturation and white in areas of 100% saturation.
Therefore on your image you can see, that the right side of her forehead as well as the shadow on her neck has extremely much saturation, especially compared to the very dark areas around them.
If you want the saturation values to be more uniform, just take a new layer in "Saturation" mode and pick a brush with two colors. One should be 100% saturated (I used red because it's easy to get, just enter 255-0-0 and you're done) and is used to saturate areas (i.e. lighten the dark parts), the other one should be 0% saturated (e.g. 0-0-0) and is used to desaturate (i.e. darken the light parts).

Color maps are indeed a little more complicated to read at first because they show all the hues plus the saturation values without the luminosity information.
Now it's really easy for your eyes to get fooled to see blue next to orange areas where there's really no color (means: that area should be gray), so what I like to do is put a solar curve on top to differentiate between the different hues.
That way it's really easy to differentiate between the different hues and unify them using Hue/Saturation adj. layers where you just shift the hue a little (that process is quite similar to dodge & burn but you're shifting hues instead of luminosity).

Edit: On a related note I'd suggest that you put another layer on top of your color map that unifies that saturation levels, e.g. a layer filled with a 50% saturated color set to "Saturation" mode on top helps to see just the hue and get rid of saturation changes (that are more easy to see using the saturation map).
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  #29  
Old 09-13-2011, 05:02 AM
adtechniques adtechniques is offline
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Re: how can i separate colors from light ?

Thank you, Der_W. I tried it on my photo, it looks right better. Although it may seem hard to realize with the naked eye if you don't turn off/on the layer saturation which you did to see again.
I also want to ask you a bit more about using this technique to matching tone. Because we know all the photos are the parameters: Hue, Saturation, luminance.
With the saturation and luminance, may seem easy to see but what about Hue? It is always orange, gray and blue. How to decompile them to create color images as we want to match?
When I use this method to get the Hue map, two images have the same Hue map. I am confused with it.
Thks you again,
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  #30  
Old 09-13-2011, 05:40 AM
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Re: how can i separate colors from light ?

As I said in my previous post, I find it fairly more easy to unify the saturation values in my hue map and put a solar curve (http://www.retouchpro.com/forums/pho...lar-curve.html) on top. That way the differences in hue will be extremely exaggerated and therefore you can see which areas need manipulation more easily.
Since the hue sometimes shifts in steps of ~20°, that's quite a minimal difference, therefore without the solar curves it's most of the time too hard to see by eye.

Edit: I guess I also showed this technique in my video about my supporting layers (although the techniques are a little outdated already but they will work nevertheless: https://www.youtube.com/watch?v=oBK83DZpdEQ)
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