Go Back   Steve's Digicams Forums > Digicam Help > Tips & Tricks

Reply
 
Thread Tools Search this Thread
Old Dec 9, 2004, 6:35 AM   #1
Senior Member
 
Tom Overton's Avatar
 
Join Date: Aug 2004
Posts: 1,458
Default

Hi;

I've got some night shots I took early last summer that have a severe colour shift towards the red end of the spectrum. I know that if I had RAW images, I could adjust the white balance quite easily, but these are JPEGs. Does anyone know a reliable method for adjusting these shots so they look natural? (Sorry I can't post an example - my home computer is in the shop.) The "correct colour cast" adjustment doesn't do quite enough to fix these shots. I've tried trial and error using colour variations on layers in Elements, but I'm sure there is a better method.

Thanks, Tom on Point Pelee, Canada
Tom Overton is offline   Reply With Quote
Sponsored Links
Old Dec 9, 2004, 8:48 AM   #2
Senior Member
 
photosbyvito's Avatar
 
Join Date: Dec 2003
Posts: 5,710
Default

hmm...i'm guessing you're talking about after the fact right?

in elements...lol, if elements has the same stuff as CS...

then, i would check in your image dropdown menu for a "photo filter", then you can apply the opposite of the color cast....

my guess, is your orangey-red night shots were caused by tungsten lighting(incadescent)....so you could just add a cooling filter in "photo filter" if elements has that option...

if not...check for "levels"

that you can select seperately the red channel, and lower the amount of red...i believe this is how it works...lol, this is more in the testing hypothosis stage...so i'm not positive...

i think "hue saturation" would work...with a bit of time playing with the sliders...

ok, i have some ideas for using layer modes to do this...so i'll try them out..and get back to you

Vito
photosbyvito is offline   Reply With Quote
Old Dec 9, 2004, 11:26 AM   #3
Senior Member
 
hedwards's Avatar
 
Join Date: Jul 2004
Posts: 190
Default

If they were outside it was probably "sulfur fume" lights like street lights.

The best way to color correct this sort of thing is with either curves, or hue-saturation.

Try desaturating red and/or saturating green and blue.
for the yellow bit try saturating the blue and/or desaturating the green and red.

Usually a combination of the above will solve it in post prod.
hedwards is offline   Reply With Quote
Old Dec 11, 2004, 4:57 PM   #4
Senior Member
 
Join Date: Dec 2002
Posts: 430
Default

The low pressure sodium (LPS) street light is popular with may municipalities because of its efficiency. The LPS produces yellow/orange spectral lines.
jawz is offline   Reply With Quote
Old Dec 11, 2004, 8:29 PM   #5
Senior Member
 
hedwards's Avatar
 
Join Date: Jul 2004
Posts: 190
Default

That sounds better.
hedwards is offline   Reply With Quote
Old Dec 21, 2004, 5:06 AM   #6
Moderator
 
Nagasaki's Avatar
 
Join Date: Jan 2004
Posts: 897
Default

I find the droppers in the levels menu to be useful in correcting colour casts.

Try Image, Adjustments, Levels. There should be 3 eye droppers on the bottom right of the pop up screen. One of these is set white point. Use this to point to something that should be white on the picture and this should give you a good starting point for fine tuning. The Set black point can also be useful but I've found the set grey point to be less easy to use as it's hard to find something that is the right shade of grey not to introduce a new colour cast. Once you've corrected the colour cast you can save the settings and load them to use on another photo. This is useful if you have a shot with white on it taken under the same conditions as another photo you want to correct with no white on it. If need be you can take a shot of white paper under the same lighting conditions adjust this then save and apply the settings to other shots.
Nagasaki is offline   Reply With Quote
Old Dec 21, 2004, 10:20 AM   #7
Senior Member
 
Tom Overton's Avatar
 
Join Date: Aug 2004
Posts: 1,458
Default

This is an example of the shots I got at the marina in July. My best inclination is to wait another seven months and re-shoot with the correct white balance. If anyone wants to have a crack at it, feel free. I'd be interested in what you come up with.

Regards,

Tom, on Point Pelee, Canada
Attached Images
 
Tom Overton is offline   Reply With Quote
Old Dec 21, 2004, 10:47 AM   #8
Senior Member
 
Tom Overton's Avatar
 
Join Date: Aug 2004
Posts: 1,458
Default

Nagasaki wrote:
Quote:
I find the droppers in the levels menu to be useful in correcting colour casts.

Try Image, Adjustments, Levels. There should be 3 eye droppers on the bottom right of the pop up screen. One of these is set white point. Use this to point to something that should be white on the picture and this should give you a good starting point for fine tuning. The Set black point can also be useful but I've found the set grey point to be less easy to use as it's hard to find something that is the right shade of grey not to introduce a new colour cast. Once you've corrected the colour cast you can save the settings and load them to use on another photo.
Here is my result using your method... (Granted, I could have taken more time) The white dropper was no use at all; everything turned neon green. The black and grey were more helpful. I experimented a little by going to the RED menu and using the grey dropper on a medium red (is that the correct process?)

Anyway, that's what I've manged so far. Using this same shot as a benchmark, I've tried about thirty different methods, including balancing the RGB on different layers (unfortunately, Elements doesn't offer channels)

Tom, on Point Pelee, Canada
Attached Images
 
Tom Overton is offline   Reply With Quote
Old Dec 22, 2004, 6:04 AM   #9
Moderator
 
Nagasaki's Avatar
 
Join Date: Jan 2004
Posts: 897
Default

Tom, I had a look at the picture you loaded up and I can't do any better than you. From what I can see some parts of the spectrum seem to be missing all together. I've tried taking pictures under street lights as an experiment and got the best results by setting the white balance before taking the shot but I've also been able to do a manual correction using the white dropper and then some fine tuning. I think though that in my case the lights were not quite the same and not as totally yellow, or else there was a small amount of white light on the scene from surrounding houses. Whatever the reason there definitely appears to be a more complete spectrum in the pictures I used just skewed towards the yellow.



Ken.
Nagasaki is offline   Reply With Quote
Old Dec 29, 2004, 10:06 AM   #10
Senior Member
 
Join Date: Jun 2004
Posts: 2,974
Default

Opanda Filter.. Hoya 80A
Attached Images
 
vIZnquest is offline   Reply With Quote
 
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -5. The time now is 5:18 AM.