Comments on: UV & Multispectral landscape photography

By: Max

Max — Fri, 02 May 2014 22:19:04 +0000

Firstly, thanks for the reply.
Secondly, I don’t have photoshop unfortunately, I use GIMP to edit most photos.
Lastly, maybe not my best move ever, but I started looking for a function that could fulfil what I described in my comment after posting the comment. It only took some five minutes to find it =w=
But yes, indeed, R=IR, G=G, B=B worked splendidly, though, at first it didn’t because of the photos not all being the same format after aplying perspective corrections. After a simple cropping it worked though.

Thanks for the info though! ^o^

By: Dave Kennard

Dave Kennard — Fri, 02 May 2014 21:53:53 +0000

In reply to Dave Kennard.

This was what I was thinking of in regards to layers, though having just tried it, it gives different results to using the channels method: http://varis.com/2013/08/19/the-new-cc-false-color-technique/

By: Dave Kennard

Dave Kennard — Fri, 02 May 2014 20:10:16 +0000

In reply to Max.

Hi Max

I think what you are probably looking to do is a channel swap. For this you need to open both the IR and Vis images in Photoshop. In the IR image select all and copy. Then go to the Vis image and view the channels palette. Select the red channel and paste in the IR image. This should now give you an image where R=IR, G=G, B=B. It should be brighter than the normal Vis image, since the IR image is likely to be brighter than the visible light red channel.

I am pretty sure there is also a way to do this using layers, it might involve using colour adjustment layers and the blend-if options. But I can’t remember off the top of my head. I’ll see if I can find the info and let you know.

Regards

Dave

By: Max

Max — Wed, 30 Apr 2014 09:21:59 +0000

That is really really awesome! Since I saw this, I made a few Visible light and Infrared light combined photos, but that purpelish look you have thanks to your UV pass filter does make yours look more interesting I think :p Also, you could try using a perspective tool to line up the photos better. It does take a lot longer to proces, but the end result is more pleasing I think.
One last thing, how do you get your photos that bright? All multispectral photos I made, were really quite dark. I know why, but I don’t know how to help it :s I simply made the IR photo completely red, so that what’s white becomes red, and what’s black remains black, then I get rid of the red colour channel on the V photo, and simply place the IR photo with 50% opacity over the other one. But since that’s not the same as actually giving a new red channel to the other photo, it ends up really quite dark. It’ll just take the average of the 2 photos, so even if the red photo is red 255, and the other photo has green and blue at 255, since those colours don’t exist in the other photo, it’ll make the end colour grey, rather than white. R= (255+0)/2 = 128
G=128
B=128
While it should all be 255.
Do you know anyway to get around that?