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Luminous Landscape Forum > Raw & Post Processing, Printing > Digital Image Processing
Jonathan Wienke
Hue/Sat is just fine, you simply need to select a color range before invoking it if you only want to tweak a specific color.
nniko
There is an inexpensive Photoshop plug-in program that makes selective color adjustment much easier, called Color Mechanic (www.colormechanic.com).  I think Michael reviewed it here a couple of years ago, and the review might still be around if you search for it.

Lisa
hovis
Thanks for both your replies.
gwelland
There is another approach - you could work with the image in LAB mode to enhance the contrast of the image from the background. It's very well suited to these types of situations although the work involved is somewhat greater than hue/sat but the results can be significantly better.

Take a look at Dan Margulis' new Photoshop LAB book for some ideas & techniques. I've been finding the approach very useful for expanding the colour contrast and range of some of my more difficult images.
Ray
QUOTE (nniko @ Sep. 07 2005,11:42)
 I'm not using it to correct for a color cast; if that's what you're using it for (and that's what it sounds like from your post), then you're right, it doesn't work particularly well, but that's not what it's for.  What I'm using it for is to modify certain specific colors (without changing other colors) where "reality" isn't exactly what you want, and that it does in a very convenient, quick and easy-to-control fashion.  For example, using it to make a bland pale blue sky a more saturated blue, or to make brownish-looking vegetation look a healthier green.  In my experience, it's very good at isolating a particular color.  How well it works must depend on what sort of images one is using it on.

Lisa,
You've just explained exactly the impression I have of SilverFast. The capacity to change the color and saturation of specific parts of the image without changing the over all color balance is quite remarkable. I can do this in a fashion that seems easier and more intuitive than curves in PS.

Of course, SilverFast also has a 'color correction' slider which is equally remarkable.
hovis
Hi

I have been trying to adjust specific colours within an image using the Hue/Saturation tool in PS. Are there any better ways of doing this? Here is an example of what I'm trying to do, the first image is the original, the second is the same image with the contrast exagerated to show the different patchs of colours.

[IMG]http://static.flickr.com/28/40569580_9c3a9abee2_o.jpg

[IMG]http://static.flickr.com/30/40569582_efc89a2974_o.jpg

Thanks
hovis
Thanks Jonathan.
Chris_T
Another tool that works well with certain images is Selective Colors. The bottomline is that the tool of choice is a function of what kind of image you are dealing with.
MarkDS
Lisa, I've used Color Mechanic, and while it works, I think one can get the same results using either Hue/Saturation in the manner Jonathan described, or the Selective Color adjustment in PSCS2. I didn't find Color Mechanic all that it's cracked-up to be in terms of really isolating the color you want to adjust. But one other observation on this matter in general - I have often found that if there is a problem with one colour, it often means that the overall colour balance is somehow off, but is more noticeable with one colour than any other. Hence when I spot this issue in some of my images, the first thing I do is verify the overall colouor balance before resorting to selective colour adjustments. Of course, this doesn't apply if the objective is to intentionally change a correct colour in a balanced image to something else for whatever reason.
nniko
QUOTE
Lisa, I've used Color Mechanic, and while it works, I think one can get the same results using either Hue/Saturation in the manner Jonathan described, or the Selective Color adjustment in PSCS2. I didn't find Color Mechanic all that it's cracked-up to be in terms of really isolating the color you want to adjust. But one other observation on this matter in general - I have often found that if there is a problem with one colour, it often means that the overall colour balance is somehow off, but is more noticeable with one colour than any other. Hence when I spot this issue in some of my images, the first thing I do is verify the overall colouor balance before resorting to selective colour adjustments. Of course, this doesn't apply if the objective is to intentionally change a correct colour in a balanced image to something else for whatever reason.


Mark:  It sounds like you're expecting something different from Color Mechanic than I (and the original poster) are.  I'm not using it to correct for a color cast; if that's what you're using it for (and that's what it sounds like from your post), then you're right, it doesn't work particularly well, but that's not what it's for.  What I'm using it for is to modify certain specific colors (without changing other colors) where "reality" isn't exactly what you want, and that it does in a very convenient, quick and easy-to-control fashion.  For example, using it to make a bland pale blue sky a more saturated blue, or to make brownish-looking vegetation look a healthier green.  In my experience, it's very good at isolating a particular color.  How well it works must depend on what sort of images one is using it on.

Lisa
MarkDS
Lisa - no; the part of my post dealing with Color Mechanic is specifically about its ability to isolate specific coloours and modify them without modifying other stuff in the process. This is what it is intended for and I just didn't find it all that super-effective relative to its stated purpose.

My follow-on comment on colour cast was a more general observation about the (sometimes) relationship between more apparent problems with one colour that could be part of a more general problem with less apparent but existant casts in all other colours. This happens, and has nothing to do with Color Mechanic.
MarkDS
QUOTE (Ray @ Sep. 07 2005,12:55)
The capacity to change the color and saturation of specific parts of the image without changing the over all color balance is quite remarkable. I can do this in a fashion that seems easier and more intuitive than curves in PS.

Of course, SilverFast also has a 'color correction' slider which is equally remarkable.

Ray, one would not normally use curves as the first choice for selective colour rebalancing because every tweak of an R, G or B curve affects every aspect of the image that has those colours or their complementaries. My first choice for that kind of selective work would be an HSB adjustment layer, where the colours to be worked on can be isolated very finely and adjusted in three ways at a time.
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