How do you correct a scan of an old photo that has gone red

Netaddict

I don't know why old photos go read instead of simply fading away.

I have attached an image as an example.

Photoshop CS5's auto color or auto tone features do a reasonable job of returning these "reddenned" images to normal but what I'd like to know is what processes did the auto color or tone do so I can dothem manually and tweak them?

jerryb4417 · Posted: Thu Mar 01, 2012 9:07 am Post subject:

hi,
first the reason photographs will turn red/orangish and sometimes other colors... is because the chemicals on the photopaper has change... many time it due to poor storage especially if too warm...

as far what does the auto features do... they do a color balance ...
1. they basically apply a curve or level ajustment to the image in general or to the individual channels...
here two tutorials
a. using levels -- http://www.bairarteditions.com/pages/tutorials/photoshop/cblevels.html

b curves -- http://www.zuberphotographics.com/content/photoshop/curves-color.htm

now there other ways to handle a color cast, but the above 2 is the most common.... and there a ton of tutorials on different ways to remove color cast/tinting, etc...

renata · Posted: Fri Mar 02, 2012 4:23 am Post subject:

If you look at the levels command via the image menu (not as an adjustment layer), you'll see that there's an "options" button.

Press this and a window comes up letting you choose different algorithms (methods). Apparently:
"Enhance Monochromatic Contrast" = Auto Contrast
"Enhance Per Channel Contrast" = "Auto Tone"
and
Auto Color is covered by "Find Light and Dark Colors" with the additional option of "Snap Neutral Midtones".

Um. That's probably not what you wanted to know, but basically you can fiddle with levels to get similar results to the auto commands.

A shortcut which sometimes works is to use the middle (gray) eyedropper in levels/curves and click on a part of the image which you know to be a neutral gray. When this works, the improvement can be dramatic. The example attached comes from one single click of the gray eyedropper in curves - still a long way to go (she's got green hair!) but it could be a starting point.

It's also worth trying to adjust the curves channel by channel. Add a curves adjustment layer and choose red in the dropdown box. Then you can tweak the other channels one by one.

Another way would be to try adding a hue/saturation adjustment layer. Clicking the 'finger' (on the left of the color dropdown box) allows you to then click in the image itself with an eyedropper and slide left/right to adjust the color you've clicked on.

Hope this helps. Good luck.

Netaddict · Posted: Sun Mar 04, 2012 12:08 am Post subject:

Hmm "color cast" so that's the term

Thank you jerryb4417 for the hint, using the three eye droppers in the curves menu did the trick, so did the three eye droppers in the levels menu. Is this like adjusting the "white balance" in a digital camera?

yes renata, the option button is a great shortcut, so are the "auto" buttons on the main window of the levels and curves windows.

I'm learning a lot from this forum

Matt · VIP

Another options would be the Variations Command, or the harder to use Colour Balance option.

Hope that helps

K-touch

Hi there,

heaps of things you can do., curves, Hue and saturation, selective colours, till you try you wouldn't know : )

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