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02/20/2008 06:28:22 PM · #1 |
Sorry i cant offer an example (havent got anything i can release to public on this one) but hopefully my problem is easily identifiable:
Basically the photo (portrait btw) looks fine in terms of colour casts before i play with the curves - white balance is all set etc etc - no problems there. When i bump the curves up to get the high contrast look the reds seems to invade the photo. I know you can get rid of this by using a luminance blend mode, but then the photo goes flat and really boring/desturated...(which is another question i have, see below). So i was wondering if anyone knew how to up the contrast to that "bleached" look, without affecting the colours - working in a non-RGB mode for instance?
As for the luminosity blend mode - i was very puzzled when, after reading the explanation given, that the luminance blend mode actually seems to deasaturate an image (proof of this comes if you just duplicate and desaturate a layer, and then apply it with luminance blending to the original image) - according to the readme the luminosity does this:
Luminosity Creates a result color with the hue and saturation of the base color and the luminance of the blend color. This mode creates an inverse effect from that of the Color mode.
Which seems to mean that the the luminance of the photo is designated by the black and whites of the layer on top, and that only the hue and saturation of the layer below is used in the blend. So if you have the original image in colour and the desaturated (flat desat btw) image above it set to luminosity - you should get exactly the same as the original... no?
Anyway - i think the two problems are slightly interlinked... if there is a way to preserve the saturation of the image using the luminosity blend mode then i have solved my problem. (doing luminosity curves and then increasing saturation globally looks really bad btw) |
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02/20/2008 11:45:50 PM · #2 |
I'm not certain what you are refering to about the "explanation given" or the "readme."
When I use the luminance blending for more contrast I:
1. Duplicate the image.
2. Choose Image/Mode/Lab Color.
3. On the Channels palette, choose only the lightness channel and copy that.
4. Paste channel as new layer and change the blending mode to Luminance.
Is/does that help or are we talking about different things? |
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02/21/2008 02:53:03 PM · #3 |
Thanks for the reply, i went back to it about 2 hours after posting thinking about the fact i asked about different modes and tried LAB mode to adjust the shot and it worked nicely. So yes your advice does help - i'll give your method a go as well and see what differences there are to the way i discovered in doing it (i used the luminance curve in lab then converted back to rgb to fiddle a bit more for some "punch").
And the "readme" refers to photoshop help under the descriptions for the different blend modes - which if i am reading and interpreting them right... are wrong in their application.
thanks again :)
Message edited by author 2008-02-21 14:53:40. |
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02/21/2008 03:42:53 PM · #4 |
If the readme you're referring to is the one posted by Adobe, then I doubt it's wrong. I would hope, after 10 releases of Photoshop, that they would know how their blending modes work.
Remember that as you increase brightness, you're going to decrease colour saturation and contrast. If a curves adjustment on luminosity blending mode is making your colours flat, did you try adding a hue/saturation adjustment to boost the colours back up a bit?
ETA: I tried playing around for a bit with desaturated layers blended over their originals in luminosity mode, and every time the images changes slightly. There must be something more going on than simply blending the lightness value, but I can't find what it is yet.
Message edited by author 2008-02-21 15:52:39. |
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02/21/2008 04:44:13 PM · #5 |
Originally posted by geoffb:
ETA: I tried playing around for a bit with desaturated layers blended over their originals in luminosity mode, and every time the images changes slightly. There must be something more going on than simply blending the lightness value, but I can't find what it is yet. |
That is what i am referring to - i think it has to do with how the image is "desaturated" in RGB mode... that was how i tested my assumption that it made the image "flat". |
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