This tutorial will show you how to stack raw images using Photoshop and adobe bridge. this will be useful for anyone wanting to make star trails etc. its pretty simple so lets get started:
I take all of my star trail photographs in the Raw mode on my Canon 60D. This is highly advantageous over taking them in the jpeg format as you can rescue photographs which have an exposure that is slightly too low for example. This is especially important in this type of photography because you are out all night taking the picture (as i explained my star trail photography guide) and you want the result to be the best possible one.
Open adobe Bridge and locate to the set of RAW images using the “favourites” menu toward the top left of the page.
press the Ctrl + A key at the same time – this will select all of the images. You can deselect the ones that you do not want to open by pressing Ctrl and clicking on it.
double click on any one of the images. You should get a message saying something like: “are you sure you want open all 148 files” – click OK to this message.
Now Photoshop camera RAW should open up. Firstly look at the menu at the top left. Click “select all” and then click “synchronise”:
What this will allow you to do is edit the picture settings which are located on the right hand side of the page and have them automatically update on all of the photos.
simply click “open image” at the bottom right of the camera raw page. Note you have to have quite a fast computer if you are opening a lot of images.
Ok, you now need to get all of the images into one PSD. do this by locating to PSD 2 and pressing Ctrl A, then Ctrl C. Locate back to PSD 1 and then hit Ctrl V. Do the same thing from PSD 3, 4, 5 and so on until all of the pictures are in separate layers on PSD 1. (you can close each PSD after you have copied and pasted).
Lets make the layers into a star trail. click on the top layer:
Now locate to the layer blend mode and select “lighten”.
Change the layer blending mode for all layers, save as a jpeg file and there is your picture complete!