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image compositing with the tri-color technique

Fenixgoon

Fenixgoon

Lifer
so i was going through my dad's astronomy magazine and they had a black/white picture. then they took pictures again with red, green, and blue filters on the telescope, then combined them (using photoshop, i think). i thought "hey, that's pretty neat." so, i pulled some b/w images off of google and made red, green, and blue filters in photoshop. i haven't been able to make a color composite with any success. I tried using a program called "picture window 3.5" to combine the images, but it didn't work--i ended up with a darker b/w picture instead. anyone have any experience with this sort of stuff? thanks.





Fenixgoon
 
What do you mean by "I made red, green, and blue filters in photoshop"? What do your "filters" consist of?

And the people taknig photos aren't taknig photos of a black and white subject. They're taking pictures of the sky. How the heck do you plan on getting color out of a black and white photo?
 
my filters are red, green, and blue "overlay" layers. these people have telescopes that can see galaxies, stars, etc. the film they use to capture pictures is black and white, not color. if you want, i'll even scan the pages out of the magazine and post them.
 
Look at the third page. Notice how the R, G, and B images all have slight disreptancies in details. Color is where the disreptancies are, depending on the intensity of the R, G, and B (eh, red, green, and blue) in one particular area. If you take a b+w image and quadruplicate it, and turn three of them into just red, blue, and green, you're not going to be able to get any color out of it, because all the images will have the same color characteristics. I'd explain this in more detail, but it makes perfect sense to me, so I'm going to assume it does for you, too. 😉
 
Isn't this what layers in PS is for?

edit: I mean the channel function. Place a b/w picture in each of the red green blue channels.
 
Originally posted by: Fenixgoon
ok.. update with scans from the magazine:
First Page
Second Page
Third Page

:beer::beer: to anyone who figures it out! 😀
Click to expand...

Well, it can't be figured out. The reason that it worked is that they took 3 pictures, each with a filter. So, each picture represents one color channel. If you import them all into ps, and tell it which one is red, which is green, and which is blue, then you get color.

There was a thread a while ago that had pictures from a guy that did this when only black and white film was available. Some group took the pictures and converted them to color using ps (he used a special projector to do it) and the result was really bizarre looking pictures because most pictures from that time are black and white. It plays with your head a bit.
 
on each of the filters (layer was set to overlay), i have 255/0/0 (red), 0/255/0 (green), and 0/0/255 (blue). so what i need to do then, is change them so they're not all 255?

or should i change the pictures slightly? rotate one 0.5 degrees CW, another 0.5 CCW, and then keep one as is?
 
Ok, if you want to take a color picture and do this in photoshop, that's a different matter. You can't do it with a single black and white image. If you have three, then one b&w image will be all the blue data. Basically, the technique is to take the image that was filtered with the blue filter, and make it monochrome blue. Then do the same for the images that were filtered with the red and green filters. Then, you'll have three monochromatic color images (one all shades of blue, one all shades of red, one all shades of green). You combine these to get a normal, true color image.

Basically with this technique, one b&w image captures everything that is blue, one captures everything that is red, and the other captures everything that is green. If you take the image that was captured with the blue filter and tint it blue, you're basically reapplying the filter, and you end up with the same blue image that you'd see looking through the camera lens.
 
Ok, let me make it REAL simple for you (since you either don't read what people took the time to write or you just don't get it). If you want to duplicate what they did, then go get a camera and some black and white film. Take 3 pictures using red, green, and blue filters without moving the camera. Scan them in, put them in photoshop as channels, and then you get color from black and white.

That's the only way to do it. There is no other way, you need three pictures of the same thing, each with a different filter.
 
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