Changing all red pixels to green in an image

How can I change all red pixels in my image to be green? Fill won't do what I want, as I have an image with hundreds of separate little red parts throughout (some only a few pixels). This would seem to be a trivial thing to do, but I can't see how you can in Photoshop CS unless they're all connected to each other, or you fill each one separately, which is infeasible for this image.

"Alex" wrote in message

How can I change all red pixels in my image to be green? Fill won't do what I want, as I have an image with hundreds of separate little red parts throughout (some only a few pixels). This would seem to be a trivial thing to do, but I can't see how you can in Photoshop CS unless they're all connected to each other, or you fill each one separately, which is infeasible for this image.

Here are two ways:

1) Convert to Lab mode, bring up curves, and invert the ends of the a channel. Use the history brush to touch up any changes you did not want

2) Use Image>Adjust>Hue/Sat and use eyedropper to select one of the red objects. Move the hue slider to get the color you want. Your changes will be limited to a specific range of red, which you may adjust with the triangular sliders.

Another powerful technique uses layer blending. Duplicate the original layer, make your changes, then convert to Lab mode without flattening. You may then use layer blending on the a and b channel to limit the changes to a certain range of colors.
--

Mike Russell
www.curvemeister.com/forum/

Alex wrote:
How can I change all red pixels in my image to be green?

Image - Adjustments - Replace Color ... click on a color you wish to replace with 'fuzziness' set to a low value, then adjust the hue (or saturation or lightness).

Alex wrote:

How can I change all red pixels in my image to be green?

.... or you can use the channel mixer.

Andrew

In article ,
"Alex" wrote:

How can I change all red pixels in my image to be green? Fill won't do what I want, as I have an image with hundreds of separate little red parts throughout (some only a few pixels). This would seem to be a trivial thing to do, but I can't see how you can in Photoshop CS unless they're all connected to each other, or you fill each one separately, which is infeasible for this image.

Step 1: Use the eyedropper to sample the red.

Step 2: Use Select->Color Range. The Color Range command selects all the pixels that are the foreground color. You can choose how far away the color needs to be before it's no longer considered the same color.

--
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You can also use the Color Replacement Tool in the Brushes Palette (CS2). I think it may have been under the Healing tools in CS, but I'm not totally sure since I skipped over that version.

Alex wrote:

How can I change all red pixels in my image to be green? Fill won't do what I want, as I have an image with hundreds of separate little red parts throughout (some only a few pixels). This would seem to be a trivial thing to do, but I can't see how you can in Photoshop CS unless they're all connected to each other, or you fill each one separately, which is infeasible for this image.

tacit wrote:

How can I change all red pixels in my image to be green? Fill won't do what I want, as I have an image with hundreds of separate little red parts throughout (some only a few pixels). This would seem to be a trivial thing to do, but I can't see how you can in Photoshop CS unless they're all connected to each other, or you fill each one separately, which is infeasible for this image.

Step 1: Use the eyedropper to sample the red.

Step 2: Use Select->Color Range. The Color Range command selects all the pixels that are the foreground color. You can choose how far away the color needs to be before it's no longer considered the same color.

I use Photoshop CS for most of my image manipulation, but I also have Thumbs Plus 7. I use this primarily for managing my photo collection (for which I consider it is excellent), but it also has some image manipulation functions. These are not particularly intuitive, so I haven't used them very much, but it will easily do some things which Photoshop doesn't handle particularly well.

It has a range of colour manipulation features: adjust colours, colour depth, colour balance, swap red and blue, invert colours, replace colours, and remove red eye. The 'replace colours' function enables you to select one colour, with adjustable tolerances on hue, saturation, etc, and either replace it with a second fixed colour, or a second colour with the same range of these properties. I haven't tried any of these functions.

It also provides a range of transforms; various rotations, trim to proportion, trim to exactly, etc. I find the trim to proportion very useful, as you can easily crop a photo to give the best fit on a particular size of paper.

I have no hesitation in recommending Thumbs Plus (and I have no financial interest whatever in the firm).

James McNangle

"Alex" wrote in message

How can I change all red pixels in my image to be green? Fill won't do what I want, as I have an image with hundreds of separate little red parts throughout (some only a few pixels). This would seem to be a trivial thing to do, but I can't see how you can in Photoshop CS unless they're all connected to each other, or you fill each one separately, which is infeasible for this image.

in layers palette
click on half moon icon
selective color
choose red in the drop down
use the sliders

Mike Russell wrote:

2) Use Image>Adjust>Hue/Sat and use eyedropper to select one of the red objects. Move the hue slider to get the color you want. Your changes will be limited to a specific range of red, which you may adjust with the triangular sliders.

This method worked very well for me.
Thanks!
Alex

KatWoman wrote:

in layers palette
click on half moon icon
selective color
choose red in the drop down
use the sliders

What / where is the "half moon" icon?

Thanks
Alex

"Alex" wrote in message

KatWoman wrote:

in layers palette
click on half moon icon
selective color
choose red in the drop down
use the sliders

What / where is the "half moon" icon?

Thanks
Alex

bottom of layers palette
adjustment layers