Jump to content

sgl_imaging_challenge_2021_4.gif.6a323659519d12fc7cafc409440c9dbf.gif

Summer Milky Way from Devon


fwm891
 Share

Recommended Posts

Thanks All for the comments.

Dipper - really not sure about Z.L. I had assumed it to be one of those colour casts. I'm still getting used to these conditions here and had not even dreamed that something like ZL might be visible?

Link to comment
Share on other sites

Thanks SJJ & Duke2k.

What I've first created here is two separate photos which overlap in content. Each of these photos is itself made up of shorter exposures (10 x 2 mins) the the 10 x 2 min exposures are stacked together in software (AA5 or DSS are most popular) and saved as single images.

These I opened in Photoshop and placed each as its own layer then rotated and tweaked as necessary to align the overlaping content of the two layers. The uppermost layer I change the blending mode to 'Difference' then as the two begin to match the overlap goes dark.

Once I'm happy (never!) with the match the upper layer bland mode is changed back to 'normal' and then I work on one layer with level/curves etc to get densities and colour to match the other layer. once that's done I merge the two layers and tweak colours and densities to give me the final image. There are lots of other little processes along the way but that's the basic way I do it.

Link to comment
Share on other sites

Thanks SJJ & Duke2k.

What I've first created here is two separate photos which overlap in content. Each of these photos is itself made up of shorter exposures (10 x 2 mins) the the 10 x 2 min exposures are stacked together in software (AA5 or DSS are most popular) and saved as single images.

These I opened in Photoshop and placed each as its own layer then rotated and tweaked as necessary to align the overlaping content of the two layers. The uppermost layer I change the blending mode to 'Difference' then as the two begin to match the overlap goes dark.

Once I'm happy (never!) with the match the upper layer bland mode is changed back to 'normal' and then I work on one layer with level/curves etc to get densities and colour to match the other layer. once that's done I merge the two layers and tweak colours and densities to give me the final image. There are lots of other little processes along the way but that's the basic way I do it.

Thanks for that Francis :) I'm just about to do similar with my Cygnus Loop mosaic :)
Link to comment
Share on other sites

Been looking at this - well trying to make something work! :D I think I'll have to leave it until I'm fresher :confused: Firstly I need to work out how to actually load two (or more) images into two different layers. I've found the Blending Mode > Difference. Then I need to find out how to move and rotate layers.... Mayeb tomorrow when I've caught up on my sleep - early night tonight (cloudy anyway). I got less than 4 hours sleep last night (this morning).

Link to comment
Share on other sites

Gina - there are various ways of doing that.

Easiest is to open all (4?) parts of your image. Presuming PC/Windows click on one image to make it active then:

CtrlA to select the whole image, CtrlC to copy the selection, CtrlN to open a new doc, click yes. CtrlV to paste the first image into the new doc as a layer.

Do the same with the other part iamges: CtrlA, CtrlC, click on your new doc to select it, then CtrlV to paste the next layer...

You then have a new doc with a layer for each part of your image and a background. You don't need the background so just drag it to the waste bin at the bottom of the layers pallet.

You will probably now need to resize your canvas so go to Image/ canvas size and enter what you think your new image size will be (best to add a bit although that does increase the file size)

Now select your top layer and change the blend mode to Difference and select the move tool. click on the next layer down to select it and you can move the layer so that it joins with the top layer and goes black where they have the same content. You may have to rotate layer two so it matches the orientation of the difference layer.

Continue then selecting layer three, move/rotate that to match the difference layer. Then any other layers treat the same. Once you have all your layers with matching overlaps you can change the blend mode of the top layer to normal again.

I find it best to just have the difference (top layer) and the layer I'm moving visible. You can link each layer (highlight difference and move layer then click on chain symbol at bottom of the layers pallet) to the difference layer so it doesn't move once you have positioned it.

Have all the layers as normal blend mode and use levels/curves/colour balance etc on each to match to 'ONE' of the layers. Once you have matched them (here you can use the eye droppers in the levels pallet to select an area (make the sample size about 11 pixels square) and sample an area that is common to the two images you are trying to match on the layer you are not altering and click OK. Then on the layer you are trying to alter click on the same location and levels will change the image (density/colour) to match the sampled area.

Do that for all your layers.

Now select all layers and duplicate them. Turn the duplicates all off - they are a back-up. Now you can select the eraser tool/brush/ (opacity and flow to 50%) and a brush size of 50 - 300 with soft edges depending on your image size. Select the uppermost layer and carefully work at the edges so there is no sharp transition between the layers.

Work your way through the layers until all overlaps have soft transitions.

If your happy at this stage click on layers at the top of the screen and almost at the bottom click on merge visible - all your layers (ecept the dupes) will become one layer. You can now duplicate that layer and work on the duplicate with curves, levels, colour balance etc until your finished...

I'd save the whole thing now as either a tiff or psd file so you can go back if need be. Otherwise flatten the image and save.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.