PDA

View Full Version : Colorizing B&W


MadSkillzMan
04-12-2005, 04:48 AM
hey guys, ive seen some amazing jobs done with people colorizing, but they always use brushes and its quite a job, and the result is that 1950's colorized image.

But i gotta wonder, does anyone know a way to do it this way?

The way i figure it, one could make a red, green, and blue copy of the BW photo, overlay them, and adjust the transparency..i tried this however and failed..

the reason i ask, is because on a older bigscreen tv, you have 3 black and white tubes, with nothing more than a color filter over them...same with early front screen projectors...why, with all our computer power cant we mimic this in photoshop?

halo
04-12-2005, 08:20 AM
you can...copy and paste the greyscale file into each R G and B channel and adjust...

berniebernie
04-12-2005, 03:33 PM
http://www.kirupa.com/motiongraphics/colorization.htm

?

whookam
04-12-2005, 04:33 PM
hey guys, ive seen some amazing jobs done with people colorizing, but they always use brushes and its quite a job, and the result is that 1950's colorized image.

But i gotta wonder, does anyone know a way to do it this way?

The way i figure it, one could make a red, green, and blue copy of the BW photo, overlay them, and adjust the transparency..i tried this however and failed..

the reason i ask, is because on a older bigscreen tv, you have 3 black and white tubes, with nothing more than a color filter over them...same with early front screen projectors...why, with all our computer power cant we mimic this in photoshop?

There's a good reason why we can't do this. By the time you have made your copy of the B&W image there is no longer any colour infomation. A black and white image has no colour channels as such (ie. all colour channels are the same). That is the point really.

If you made 3 copies with a red, green and blue filter then you will get 3 RGB Images of the same monotone image tinted red, green and blue. The filters can't filter any colour because there is no colour to filter!

TVs and such (to simplify things a bit) send different 'grayscale' images to each filter to produce a colour image. I can promise you it won't work otherwise I would have made millions of pounds 'colorising' peoples old images.

halo
04-12-2005, 06:45 PM
If you made 3 copies with a red, green and blue filter then you will get 3 RGB Images of the same monotone image tinted red, green and blue. The filters can't filter any colour because there is no colour to filter!

yes there is...because you have placed the greyscale image into each RGB channel its there, but it looks neutral because its in balance, the channels are all the same. A filter blocks light, so recreate the block effect by painting black into one of the channels and you will see colour appear...of course you can paint white and see the colour shift the other way. You are essentially painting the filter as you go....try it...i hope you understand the theory.

RGB works exactly the same in PS as it does in TV screens and monitors and film projectors.

Pretorian
04-13-2005, 09:16 AM
halo: maybe this will sound a little too newbie, but, how exactly you mean by "copy and paste the greyscale file into each R G and B channel and adjust"? How would I made this?




Thanks

whookam
04-13-2005, 12:16 PM
yes there is...because you have placed the greyscale image into each RGB channel its there, but it looks neutral because its in balance, the channels are all the same. A filter blocks light, so recreate the block effect by painting black into one of the channels and you will see colour appear...of course you can paint white and see the colour shift the other way. You are essentially painting the filter as you go....try it...i hope you understand the theory.

RGB works exactly the same in PS as it does in TV screens and monitors and film projectors.

Yes, if you have different grayscale images in each channel then you will get colour in the RGB composite. But how do you know how to alter each channel? How can you from a grayscale image simulate how a red channel filters each and every colour? You can't, a grayscale is tone only and hold no colour infomation. Therefore your filtered images will be tone only.

So at this point you have three tone only images with differing hue. How does this help you recreate the colour? Sure alter the image in each channel and you will get shifts and variations in colour but does it look realistic? No.

To make it even simpler. You are saying that if you took a colour image and destaurated it to represent a B&W image, then made 3 copies using red, green and blue filters and the copied each image into the respective channel of an RGB image and then 'paint' each channel to create variation and thus colour you will eventually be able to match the original colour image? To get the original image, each channel you 'paint' must be exactly the same as the channel of the original. Since your 'image' in each channel bears very little resemblence you would have to individually change every pixel to the correct luminance. So essentially you would have to recreate the image from scratch, 3 times!

I understand the theory fine, I hope you are good at 'painting'!!!

halo
04-13-2005, 12:49 PM
The way i figure it, one could make a red, green, and blue copy of the BW photo, overlay them, and adjust the transparency..i tried this however and failed..

the reason i ask, is because on a older bigscreen tv, you have 3 black and white tubes, with nothing more than a color filter over them...same with early front screen projectors...why, with all our computer power cant we mimic this in photoshop?

that was the original question...and yes its possible using the above method i described that mimics the same thing as 3 b&w guns with filters...no its not easy...never said it was.;)

There used to be lunatic airbrush artists around that used to paint with Pasche turbos using just translucent C Y M K inks, laying each colour as a pass...laying the right colour down in the right percentage so that on the final colour it represented the correct composite colour...absolute lunacy and one hell of an amount of control and prediction which was largely the purpose to demonstrate that...but its possible...just not practical imo (probably a lot of peoples opinion as well)...same would apply to using the RGB channels, by shifting using colour tools like levels you will be able to offset the channels data therefore creating creating colour. Dodge and burn would probably be the easiest tools to use.

I prefer the route of just painting on a layer over the top of a b&w image with the layer set to "colour"...

Swizzle
04-13-2005, 07:03 PM
These links may be of some use:
http://www.worth1000.com/tutorial.asp?sid=161018
http://www.worth1000.com/tutorial.asp?sid=161015

I'm pretty sure the best anybody can tell you is to experiment with different techniques and see what works best for you. I don't think there's any "trick" way to colorize images, so just play around with it. (and make sure to share your reults! :) )

MadSkillzMan
04-22-2005, 07:01 PM
whookam is right it wont work..it dawned on me the other night. You can veiw B&W images on a bigscreen tv..DUH...yea, sometimes they have a blue or red tint (tvs fault) but yea it makes sense why you cant.

CGTalk Moderation
04-22-2005, 07:01 PM
This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.