how to replace a channel

[Jerryb]

hi,
First I consider myself a Novice but i can get around PS and I would like to say you guys have help me a lot.. I even getting to the point where I see a picture and can see more details in a picture and can predict how you guys are going to handle the picture... I am making progress.. smile

now my problem....

I am repairing a family picture that has a very strong red-yellowish tint , where it blots out all other colors, the problem to the picture probably cause either by poor developing or heat.

Now...

The Red channel has the details but very whitish as expected
the green channel has nice contrast and sort of look as normal channel
The Blue channel is dead, by dead i mean it almost all solid black with almost no details to work with, no amount of brightness/contrast/curves etc..will help that channel... smile... there just no details there!

I have seen where some posters have "replaced" dead channels but I have been unable to determine exactly how they do it... it second nature with them... and I figure there a couple of steps I am not aware of.

So how do you go about converting let say a green channel into a blue channel?

Now i have gone in and just, using masking , re-colorize the picture and such gotten fair picture but I would like to try and replace the dead channel where I get the natural colors back if possible.

thank you for any help you can give me

[Kraellin]

i'm assuming you're using photoshop here, so i'll let a ps user help you with this. photoshop does channels much better than psp.

if you were using psp, you would split the channels into 3 separage gray scale images with the split command. you can then recombine them by telling the combine command to use the red, green, blue, or, any combination of those you wanted to. so, you could use a red, green and red again if you wanted.

in photoshop i'm sure you can do the same thing, but it's probably all done on layers or drag and drop.

but, i'll also say this, it may not be necessary to replace the channels. it's just another method. i often can fix things others do by replacing channels and i just do it in rgb mode with other tools.

[CJ Swartz]

Jerry,
Here is a link to an RPro tutorial explaining one way to replace a color channel. It uses the blue channel as the example, which should help you. The resulting image will still have color problems, but it might be easier to work with than the copy with a damaged channel.

http://retouchpro.com/tutorials/?m=show&id=23

I notice that Craig has posted while I was writing -- it's certainly true what he says about other methods that might work without replacing a channel. You said that you wanted to learn how to replace a channel, and even if it isn't the cure for this image, it's a good technique to start learning.


Added info:
There are different ways to do the same or similar things in Photoshop -- I don't want to confuse you with a bunch of different directions all at once, but take a look at this thread where Flora explains some things about channels also. Take it easy, ask questions if you need to, remember we ALL started off not knowing what to do with channels at first and we ALL had to learn. Ro has some excellent threads where he explains different ways of dealing with replacing channels also (I'm not sure just where those threads are, but reading Ro's and Flora's posts are always an excellent learning experience -- you can learn a lot while you are looking for the post you wanted to find .

http://www.retouchpro.com/forums/ima...html#post76207

[Jerryb]

hi,
thank you for your reply and yes I use photoshop CS ... I should have been explicit in that.... my apology.

I'll see if I can translate the PSP into PS CS procedure....

Originally Posted by Kraellin

i'm assuming you're using photoshop here, so i'll let a ps user help you with this. photoshop does channels much better than psp.

if you were using psp, you would split the channels into 3 separage gray scale images with the split command. you can then recombine them by telling the combine command to use the red, green, blue, or, any combination of those you wanted to. so, you could use a red, green and red again if you wanted.

in photoshop i'm sure you can do the same thing, but it's probably all done on layers or drag and drop.

but, i'll also say this, it may not be necessary to replace the channels. it's just another method. i often can fix things others do by replacing channels and i just do it in rgb mode with other tools.

[Kraellin]

you're welcome.

and please, dont take what i said as an invalidation of working on channels separately. it's often a very good technique for fixing things. so, a good knowledge or working with channels is a valuable tool.

i'm also fairly sure that the adobe site or adobe helps will have something on working with channels as well.

[skydog]

cj,

I could not get you first link

http://retouchpro.com/tutorials/?m=show&id=23

the second was fine.

[CJ Swartz]

Originally Posted by skydog

cj,

I could not get you first link

http://retouchpro.com/tutorials/?m=show&id=23

the second was fine.

Hmmm, I don't know what the problem is -- the link works fine for me, skydog.
The link is to a tutorial by Jakaleena -- go to the tutorial section here and do a search for "channel" or the full title, "Replacing a Color Channel".

[Jerryb]

hi Cj,
Thank you very much for the link.... I have already gone thru and it works like a charm... i'll do it a few more time just to make sure i got it down right...

It does make doing adjustments a lot easier . I am not sure if I will be able to get the natural colors of the picture but learning replacing channel will be invaluable on other things.. again thank you for the link...

And I will definitely take a look at that other link you gave me. I read briefly there work in that link and i can learn a lot there...

and I definitely know about taking it slow and easy at in learning some of the features and techniques.. with photoshop.. smile... I am slow learner but I will get there... again thank you for help

Originally Posted by CJ Swartz

Jerry,
Here is a link to an RPro tutorial explaining one way to replace a color channel. It uses the blue channel as the example, which should help you. The resulting image will still have color problems, but it might be easier to work with than the copy with a damaged channel.

http://retouchpro.com/tutorials/?m=show&id=23

I notice that Craig has posted while I was writing -- it's certainly true what he says about other methods that might work without replacing a channel. You said that you wanted to learn how to replace a channel, and even if it isn't the cure for this image, it's a good technique to start learning.


Added info:
There are different ways to do the same or similar things in Photoshop -- I don't want to confuse you with a bunch of different directions all at once, but take a look at this thread where Flora explains some things about channels also. Take it easy, ask questions if you need to, remember we ALL started off not knowing what to do with channels at first and we ALL had to learn. Ro has some excellent threads where he explains different ways of dealing with replacing channels also (I'm not sure just where those threads are, but reading Ro's and Flora's posts are always an excellent learning experience -- you can learn a lot while you are looking for the post you wanted to find .

http://www.retouchpro.com/forums/ima...html#post76207