After I tried this I can see this being useful in antique maps. It adds something of an orange and blue color tone in soft light mode and a red to gray in multiply mode. Playing around with the other modes, I like overlay and pin light.
This is a Scott Kelby trick (well he learned it from someone else) I learned reading one of his books to improve photographs to get the colours of your image more punchy.
Image>mode>lab colour
Image> apply image
Then choose either lab colour, a or b in the drop down menu and make sure you either go for soft light or multiply...
may give your map an interesting colour twist.
After I tried this I can see this being useful in antique maps. It adds something of an orange and blue color tone in soft light mode and a red to gray in multiply mode. Playing around with the other modes, I like overlay and pin light.
If the radiance of a thousand suns was to burst at once into the sky, that would be like the splendor of the Mighty One...I am become Death, the Shatterer of worlds.
-J. Robert Oppenheimer (father of the atom bomb) alluding to The Bhagavad Gita (Chapter 11, Verse 32)
My Maps ~ My Brushes ~ My Tutorials ~ My Challenge Maps
I was intrigued to see this effect and so I tried it on my map with some interesting results.
The one I thought was most interesting was when I selected channel A and Linear Light blend mode. It left my landmass pretty much alone but gave my oceans a nice blue colour, like a light ink wash.
I think it looks quite cool.
Vaniya16 - alternate.jpg
Incidentally, I'm not sure why (I'm sure someone could tell me) but when I view an image in PS the colour range is significantly different to when viewed in Windows picture viewer or in Firefox. For instance, the image I have posted seems to lose some green in the transition, the new blue colour for instance seems to lack a greenish tinge that shows in the original in PS which is a shame. I imagine it is something to do with the "Color Settings" in PS but I have no idea what they should be set to. :S
Royal: I'm very sorry for your loss, your mother was a terribly attractive woman.
My Cartographer's Guild maps: Finished Maps
More maps viewable at my DeviantArt page: Ramah-Palmer DeviantArt
Heh, Ramah, you could wrap your map in a canvas bag and it would still look superb!