How to combine BW images into colour

[axiom]

With a BW-only M10 around the corner, I wonder how one combines BW images into a colour photo.

I recall having seen some century old colour photos taken with BW films and various colour filter, then blend the colour filtered images into one colour photo. If M10 only does BW-only, applying this century old trick is the only way to get a colour pic out of an M10.

So could someone post an exact steps of such a procedure?
Such as what colour filters to use, what exposure bias for each colour filtered shot, how to blend them into a single colour shot in post processing etc...

By the way, do we have colour films with 3 dye layers today?

edit: Sorry, this is a question, not really a How-to. Could MOD add a question mark or two to my title please.

 

[pdexposures]

A video I did on it

www.youtube.com/watch?v=S28OUlavAvg

For the filters I was using, the red and green filters were both 1 stop under the blue filter. Made it easy to shoot pretty quickly actually.

A few of the ones I have done

http://www.flickr.com/photos/pdexposures/sets/72157628412628585/

And a blog post I did talking more about it

http://blog.pdexposures.com/2011/12/trichromial-era.html

 

[Tim Gray]

It's pretty straight forward. You just need three color filters. Photoshop makes it a lot easier too. I'm guessing my method is a little different than pdexposures method, but the details aren't that important.

Basically, make three exposures, one through each of the filters, red, green, and blue, (I used 25, 47, and 58). I wanted proper exposures for each of three exposures; you can adjust the balance between them later in Photoshop.

I aligned them in Photoshop in different layers - you could do it by eye, but I used the Auto-Align tool. Select your all three layers, then do Edit->Auto-Align Layers... This will stack all three layers properly.

Then color the three layers appropriately. There's a couple ways of doing this. You could copy the contents of each layer to the appropriate channel. I personally set all the layers to 'lighten' and add a new coloring layer to each of the three layers, with the following options: mode: 'darken' and 'use previous layer to create clipping mask'. Then fill each of the three new layers with R, G, and B respectively. All done.

http://www.flickr.com/photos/tgray1/sets/72157613514418888/

 

[EdwardKaraa]

IIRC, older Sinar backs took 3 shots while alternating RGB filters to create a color file.

 

[axiom]

Good info.
Thanks!

 

[Pablito]

With a BW-only M10 around the corner

Last I heard that was a rumor...

and beyond that, I'd just have to ask WHY?

I can think of two reasons... an experiment just for fun, or for teaching purposes.

or

some sort of artistic alternative process to achieve a certain "look" unobtainable any other way.

but beyond that... WHY?

 

[RSilva]

This is awesome.

 

[MartinP]

Also amusing is making the three exposures on the same frame of colour film. Moving details in the picture become coloured ghosts and static parts can be (more or less) balanced to look normal.
🙂

 

[axiom]

Last I heard that was a rumor...

and beyond that, I'd just have to ask WHY?

I can think of two reasons... an experiment just for fun, or for teaching purposes.

or

some sort of artistic alternative process to achieve a certain "look" unobtainable any other way.

but beyond that... WHY?

To take colour pictures?