From: Walter Lickteig <wflyer@adelphia.net>

Date: November 25, 2006 3:47:08 PM MST

To: Astro_IIDC@yahoogroups.com

Subject: Re: [Astro_IIDC] LRGB Processing Help!!

Ray,

What you should have when you open each of the Red, Green, and Blue images is the same info [data] in each channel.  If it isn't exactly, in PS turn each RGB image to Grayscale before proceeding.  This will force the data to combine.  Then reverse the process for the Red Image, set it back to RGB under Image> Mode

Starting with your previously Red stacked and aligned image.  Copy and paste the Green and Blue on top of the Red as separate layers. Make one layer invisible by clicking on the eye in the Layers window/palette.  Set the layer blending mode to difference.  Align one layer and then the other.

Crop as noted before so each image [layer] has data.

Then change to the Channels [versus Layers] and copy the Green Layer into the Green Channel and similar for the Blue. Discard the Blue and Green Layers [or just keep them invisible but below the original Red Layer.  Normally I discard/trash them.  Flatten the image and save.  You now have a aligned RGB image.

Again paste your Luminance Image on to the new RGB image.  Use Layer Difference Blending Mode to align.  After aligning set the Luminance Image to Luminosity in the Layers Blending Mode.

And there you have it..

Walt

On Nov 25, 2006, at 12:10 PM, Ray Byrne wrote:

Hi Walter

I'm using a mono camera, the DMK 21AF04, with a filter wheel. The luminance is through a clear but UV/IR blocked filter the Red is not UV/IR blocked, the Green and Blue are UV/IR BLocked. The resultant tif files after stacking/ processing in Astro IIDC give me an RGB tiff not a greyscale file? I've got this set-up as it is for planned Saturn imaging as soon as I get clear skies.

On 25 Nov 2006, at 19:18, Walter Lickteig wrote:

Ray,

Are you shooting with a color camera or B&W with color filter wheel?

If you are shooting with a color wheel then there will be a Red "grayscale" image, a green "grayscale" image and a blue "grayscale image.

Each of these images will become one of the respective channels in RGB.

With respect to luminance data layer, most of the time I leave it at 100% [layers blending mode].  And just to note,your luminance image should been captured with either no filter or a clear filter...

Walt

On Nov 25, 2006, at 9:08 AM, Ray Byrne wrote:

Hi Walt,

Suppose as in my case the various channels don't line up? I'd know how to tackle this with layers but I can't nudge the different channels as PS won't let me :o[

Actually to clarify things for myself  I've annotated your kind instructions below. I am very familiar with PS BTW I use it all the time for work

On 25 Nov 2006, at 15:31, Walter Lickteig wrote:

Ray,

The process is pretty straightforward in Photoshop.  I normally start by opening the Red, Green, and Blue Images.

By images do you mean the combined RGB channel of each of the filtered R, G, B images?

I select the Red Image - make sure the to check Image > Mode > RGB is selected - not grayscale..  Next Open the Layers window and select Channels. You will now see each of the channels - R, G and B.

Then respectively select the Green then Blue Images and paste them into their respective channels.  After assembling the RGB, I save under a new name, e.g. Stars RGB.psd.

Then switch back to the Layers mode, and open, select and then paste the Luminance image in (on top of) the new RGB image.  And finally, select the Luminance Layers Blending mode from the Layers Window.

Do you mean luminance in the blending mode? and do you fiddle with this (ie its transparency) to get a satisfactory amount of colour coming through?

Thanks walt for your help

Ray

That's all there is to it...

Walt Lickteig