Thursday, September 1, 2016

Processing Star Trails

We had our second processing session with Dave. This time we focused on Star Trails. Dave also has an excellent YouTube video about this!
  1. First, load all images into Lightroom
  2. Pick one image to work on.
  3. Adjust White Balance
  4. Increase contrast (to get the star trails out well): move histogram to the right and black point to the right.
  5. Adjust exposure
  6. Increase Whites (brighten stars)
  7. Don't touch blacks - or even lower it to make sky darker.
  8. Now do the same as for the Milky Way shots.
  9. Go back to Library view
  10. Select image, right click, select "Developer Settings" -> "Copy Settings" -> "Select all" -> "Copy"
  11. Then select all images and click "Sync All" - now all settings from the first image are applied to all other images.
  12. Now, right click (all images still selected!) and export to JPG (PSD or TIFF would require A LOT of memory as all images have to be loaded at the same time into Photoshop)
  13. Open Adobe Bridge
  14. Select all images
  15. Load in Photoshop as layers
Now, Photoshop opens with all those images as layers (might take a while!)
  1. Pick a file that has a good foreground (no light pollution, some details...)
  2. Rename it to "Base Layer" and move to bottom of the stack
  3. Select all other Layers
  4. Group them together (name "Star Trails or so)
  5. Change Blend Mode for all images to "Lighten" (this picks the brightest pixel of each image for the result making all star trails come out - but it also picks up all of the light pollution and plane streaks :-(
  6. Temporarily move the group down
  7. Add a layer mask to the "Base Layer" image
  8. Add a lot of contrast (make foreground black and sky VERY bright) by moving midtones to the left and black point to the right)
  9. Use Dave's Actions
  10. Remove this layer and move Star trails back to the top
  11. Now select a channel where the foreground is white and the rest is black
  12. Add it as a layer mask to the Star Trails group and paint into it to reveal the foreground from the Base Layer image
  13. Now cleanup plane trails with the Stamp tool (Dave did it on the entire image, I found it easier to do on each individual image - though it takes A LONG time!)
  14. Now delete all channels and run Actions again - now we have the real channels for our image
  15. And now process the image similar to the Milky Way image:
    1. Pick an area / objects to modify (e.g. make stars brighter)
    2. Select mask where area / objects are white
    3. Pick Adjustment
    4. Make adjustment
    5. Create Group
    6. Add Layer Mask and reveal/hide the area
  16. And at the very end remove noise from the foreground as before.