ICEINSPACE
Moon Phase
CURRENT MOON
New Moon 0.3%
|
|
11-05-2011, 06:25 PM
|
Registered User
|
|
Join Date: Apr 2006
Location: Alans Flat
Posts: 375
|
|
RGB and Luminance?
Might sound dumb but I understand where the RGB files and channels come from. But I'm shooting with a DSLR. Where does the Luminance layer or channel come from.
Is it shot with an additional filter then combined in photoshop?
I'm about to get into the buying filters game and any guidance would be appreciated appreciated.
Cheers
Carl
|
11-05-2011, 06:38 PM
|
|
IIS Member #671
|
|
Join Date: Dec 2005
Location: Canberra
Posts: 11,159
|
|
DSLR's are one shot colour devices, meaning that RGB is captured along with whatever luminance data there is mixed in the one system.
H
|
11-05-2011, 06:45 PM
|
Registered User
|
|
Join Date: Apr 2006
Location: Alans Flat
Posts: 375
|
|
L-rgb
Thanks Humayan
Would this mean; for example; that if i were to image a nebula with my modded DSLR using a UV/IR filter then used a 12nm H-Alpha filter to gain vital information in that nebula, would i then introduce the H-Alpha image as a channel or as a layer over my original image?
Any suggestions
Cheers Carl
|
11-05-2011, 08:13 PM
|
|
Bust Duster
|
|
Join Date: Nov 2008
Location: Brisbane, Australia
Posts: 4,846
|
|
Sounds like you're confusing mono camera techniques and DSLR techniques.
If you use a Ha filter on a DSLR, you're still capturing RGB data, it's just that the majority of that data is in the R channel because that's what the Ha filter is letting through. G and B data will just be noise.
Do you have a colour image and want to use Ha as a luminance layer? If so, just put the RGB image in one layer, the Ha in another. Set the Ha layer blend mode to luminance and the RGB one to colour.
|
11-05-2011, 08:27 PM
|
|
IIS Member #671
|
|
Join Date: Dec 2005
Location: Canberra
Posts: 11,159
|
|
You're welcome, Carl.
+1 what Troy said.
H
|
11-05-2011, 08:35 PM
|
Registered User
|
|
Join Date: Apr 2006
Location: Alans Flat
Posts: 375
|
|
Combining images
Hi Troy
Thanks for the reply. So am i over complicating the issue? to be honest I just want to get one of those stunning images that we see on our site.
Is it simply a matter of; for example;Creating a finished 5x 5min stack (H-Alpha) and importing that finished file as a layer in Photoshop above my combined RGB image.Then using the layers palate to set the blending mode.
Or is there something special i have to do to create a luminance layer?
I've been using Photoshop for 10 years now and there are always things that dont sink in first, second or sometimes third time round.
regards
Carl
|
11-05-2011, 08:42 PM
|
|
IIS Member #671
|
|
Join Date: Dec 2005
Location: Canberra
Posts: 11,159
|
|
You've got the right idea, Carl.
If you had a monochrome system, you could even potentially mix some red into the hydrogen alpha to avoid the composition taking on that pale disgusting salmony-pink appearance that hydrogen alpha introduces as a pure luminance layer.
H
|
11-05-2011, 08:44 PM
|
|
Looking Down From Above
|
|
Join Date: Dec 2005
Location: Cootamundra, NSW
Posts: 1,711
|
|
Carl
What version of ImagesPlus are you using, if you are using IP4+ you can make a Luminance image to work on using the Split Luminance command under the Colour Menu.
Cheers
Last edited by JohnG; 11-05-2011 at 09:00 PM.
|
11-05-2011, 08:48 PM
|
Registered User
|
|
Join Date: Apr 2006
Location: Alans Flat
Posts: 375
|
|
Filters continued
Hi Humayan
I dont have a monochrome camera, mines a single shot DSLR canon modified.
So the H-Alpha will have a horrible Salmon hue, not good. So how do i get around that or am i better off just sticking with my UV/IR filetr
Regards
Carl
|
11-05-2011, 11:00 PM
|
Registered User
|
|
Join Date: Oct 2006
Location: Australia
Posts: 4,646
|
|
Hi Carl, There is a couple of ways to incorporate Ha into a one shot colour frame. No real easy way to get quick and acceptable results though. Using images plus you should be able to separate the luminance layer from the original image. Ha can be blended into this layer using Photoshop. You should also try to blend the Ha into the red channel after separating the RGB channels in IP. This will help to strengthen the red and prevent the image with only Ha in the luminance channel turning quite pink.
You can also blend a small amount of the Ha into the blue and even the green channels in varying amounts to ensure an even spread of colour throughout your image.
Ha blending is not as easy as just blending it into your luminance layer if you want premium results.
|
Posting Rules
|
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
HTML code is Off
|
|
|
All times are GMT +10. The time is now 09:08 AM.
|
|