Google Groups no longer supports new Usenet posts or subscriptions. Historical content remains viewable.
Dismiss

How to Align RGB channels in photoshop ?

1,267 views
Skip to first unread message

Duncan Galbraith

unread,
May 31, 1998, 3:00:00 AM5/31/98
to

Hi,

My scanner has a misalignment in the Red, Green and Blue channels, so that
scans appear blurred with, for example, green pixels shifted to the left,
and red pixels shifted to the right.

I need to re-align the channels.

Is it possible to do this in Photoshop ?

If so how ?

Thanks for any help..

Duncan Galbraith

SG

unread,
May 31, 1998, 3:00:00 AM5/31/98
to

Use the Channels (Window>Show Channels). Have RGB switched on but not
active. Select the channel you want to alter then use the arrow keys to
move a pixel at a time.

Duncan Galbraith <dgalb...@geocities.com> wrote in article
<01bd8cc9$7d4aa140$610f2cc3@m00mz700>...


> Hi,
>
> My scanner has a misalignment in the Red, Green and Blue channels, so
that
> scans appear blurred with, for example, green pixels shifted to the left,
> and red pixels shifted to the right.

> <snip>

Andrew David

unread,
May 31, 1998, 3:00:00 AM5/31/98
to

I don't know if previous versions are like this, but in Photoshop 5 you
have to "select all" after making the desired channel active, or else
when you try to move the channel you'll get the message, "Could not
nudge the data because the target does not include all of the composite
channels."

SG wrote:
>
> Use the Channels (Window>Show Channels). Have RGB switched on but not
> active. Select the channel you want to alter then use the arrow keys to
> move a pixel at a time.
>

> Duncan Galbraith wrote:
> > My scanner has a misalignment in the Red, Green and Blue channels,
> > so that scans appear blurred with, for example, green pixels shifted
> > to the left, and red pixels shifted to the right.
> > <snip>

Regards,
Andrew David

Andrew David

unread,
May 31, 1998, 3:00:00 AM5/31/98
to

Regarding my last post: this is only true when you want to move channel
data in an image with multiple layers, which should not apply to
Duncan's scans. Sorry for muddying the issue.

Kirk Hobart

unread,
Jun 1, 1998, 3:00:00 AM6/1/98
to

"SG" <Simondot...@btinternetdot.com> wrote:
>Use the Channels (Window>Show Channels). Have RGB switched on but not
>active. Select the channel you want to alter then use the arrow keys to
>move a pixel at a time.

Yes.

My 400 DPI scanner's green channel is misaligned by 1/2 pixel, so I do
an extra step. I resample the image to 800 DPI (or scan at 800 DPI),
then nudge the green channel by one pixel, then resample to 400 DPI.
Works great!

0 new messages