Aligning images in PS CS2 - Help please

[Tamtarn]

I want to align two images in Photoshop CS2 before layer masking.

I can't find out how to do this.

I tried the HDR in PS but once aligned the result is very weird. Looking nothing like a normal image at all bright red yellow green etc. It's said that then converting to a 16bit tiff the image then converts to normal......It doesn't

Has anyone the time to put a step by step instruction on how to align two images in PS CS2 ?

I would appreciate any help at all

Thanks

Barb

[iceman (Mike)]

Hi Barb

Have you seen this? http://www.astropix.com/HTML/J_DIGIT/LAYMASK.HTM

[[1ponders] (Paul)]

It's fairly straight forward Barb.
Open the two images in PS
Select the mover tool (V Key)
Drag one image onto the top of the other. (If you hold down the Shift key at the same time the dragged image will automatically be centered)
In the layers box select the blending option as "difference"
Now use your move mouse or arrow keys to move the top layer until the whole image turns black or as close to as possible. Once the two images line up in difference blending mode the top object automatically subtracts from the bottom object.

Once aligned select normal again.
Done

[[1ponders] (Paul)]

If there is a rotational problem then you will need to go into Edit>transform>rotate and use the corner handles to rotate the image. You need to be in difference mode again to do this to see when it is aligned.

Unfortunately with both these methods you are limited to whole pixel movements, which sometimes aren't accurate enough. But if you don't have Registar then what can you do.

Save for Registar.

[Tamtarn]

Thanks Mike and Paul I'll try your suggestions

[Geoff45 (Geoff)]

Originally Posted by [1ponders]

Unfortunately with both these methods you are limited to whole pixel movements, which sometimes aren't accurate enough. But if you don't have Registar then what can you do.

Save for Registar.

There is a compromise. Resize your images to 4 x bigger, then do the align, then resize down. This gives quarter pixel accuracy, but at the cost of degrading the image somewhat. Unfortunately, there are no free lunches!
Better would be to use dedicated Astro software, such as Registar.
Geoff

[[1ponders] (Paul)]

Thanks Geoff, I'd forgotten that little trick.

Shows how long its been since I used PS to align an image