This Tutorial published at http://www.retouchpro.com

How to Repair a Light Leak or Stain.
Posted by: Cameraken on 12-31-1969.

"Any picture which has been affected by a light leak or stain usually has two problems 1) The luminosity changes (fading) 2) The colours change (very often turning red or orange) These marks will be different for every picture so I will try to describe more general methods that should work for most light leaks. This tutorial was written in PS7 however it should easily translate to CS."

How to Repair a Light Leak or Stain.

 

Or how to get from this to this.

 

 

 

Any picture which has been affected by a light leak or stain usually has two problems

 

1) The luminosity changes (fading)

2) The colours change (very often turning red or orange)

 

These marks will be different for every picture so I will try to describe more general methods that should work for most light leaks.

 

I find the easiest way to tackle these is in two steps. First repair the luminosity (i.e. get a good B&W) and then repair the colour.

 

This tutorial was written in PS7 however it should easily translate to CS. CS has shadow highlight and match colour etc which should also be useful.

 

Let's work through this example picture. It was taken by Bill Cotter and was originally posted here

http://www.retouchpro.com/forums/photo-restoration/20065-help-please-light-leak-damaged-slide.html

 

 

 

Right click this picture and save if you would like to follow along, or there is a larger version (400kb) available here

http://www.cameracentre.co.uk/tutorials/photoshop/lightleak/braniff.jpg

 

Make three copies and convert one to cmyk and one to L*a*b and take a look at all the channels. What we are looking for is a channel with good detail, especially in the faded areas

Sometimes I will even look at the HSL channels - Anything to get a good luminosity.

 

With some images it is necessary to combine two or more channels and very often the fading is not uniform and graduated Masks are required to equalise the fading The Lab L channel is usually a good starting point but in this case it contains luminosity from the red channel which is degrading the image

 

The idea is to "Loosely select the light/faded areas and use levels (or curves) to repair"

 

I normally drag the channels out onto layers to make the repairs. This gives much more control, especially if graduated masks are required. On this occasion and for the sake of simplicity I've made the repairs directly on the channels

 

Back to our picture

 

Step1 - Repairing the Luminosity.

 

In our picture I decided to use the RGB channels because the CMYK and Lab gave no advantage

The image is not straight but the light leak is so it makes sense to leave it like this as we can use the rectangular marquee tool to select the damaged area.

 

The following adjustments can be made 'by eye' or the eyedropper may be used

 

Step 1a)

Copy the image to a new layer (never work on the original)

Click the channels tab and click on the red channel.

Use the rectangular marquee tool to select the damaged area (I used a feather of 10)

Click Image > Adjust > Levels and adjust to repair the fading.

I used 143  0.42  255  Click OK. Do not cancel the rectangular marquee

 

 

 

 

Step 1b)

Now click on the green Channel (The same selection is now available to use again)

Click Image > Adjust > Levels and adjust to repair the fading.

I used 43  1.00  255 Click OK. Do not cancel the rectangular marquee

 

 

 

 

Step 1c)

Now click on the Blue Channel (The same selection is now available to use again)

Click Image > Adjust > Levels and adjust to repair the fading.

I used 0  0.76  255 Click OK. Now you may cancel the rectangular marquee

 

 

 

Here are the results so far

 

 

It will have been noticed in doing this that the red channel is in pretty poor shape. It is very noisy and also has an extra band from the light leak. Rather than repair this I decided to discard it (there is not much red in the image anyway)

 

To remove the red channel I used channel mixer

 

Step 1d)

Add a channel mixer adjustment layer

Check the monochrome box

0% Red

80% Green

72% Blue

 

 

Normally the mix of the channels should add up to 100%. This would keep the image at a similar brightness. By using 152% the image has been significantly lightened.

The plane looks much better but the sky is now 'blown out'. We will put the sky back when we add the colour.

 

Our Luminosity is almost done.

 

Step 1e)

Add a blank Layer and Clone out the last few remaining marks

 

Step 1f)

Add a blank layer set to overlay and paint with soft brushes at 1% - 5% opacity to even out any remaining unevenness.

I also used this to lighten the plane and darken the houses.

If you are not familiar with this technique then see this tutorial

http://retouchpro.com/tutorials/?m=show&id=206

 

Step 1g)

Rotate the image straight and clone in the missing corners etc.

 

Step 1h)

While the image is in B&W this is a good time to sharpen the image.

 

Here is our finished luminosity

 

 

 

Step 2 - Put the colour back

 

Now that the luminosity is repaired we need to add the colour back. Knowing that the luminosity is repaired means that all we need to do is add blank layers set to colour blending mode.

 

Step 2a)

Drag a copy of the layer we created by steps 1a, 1b and 1c (ie. Background Copy 2) to the top of the stack and set blending mode to colour.

 

 

This adds back the original colour to our repaired luminosity.

 

 

 

Step 2b)

Fixing a blown out sky

Our sky is white and so cannot be coloured in the normal way

I used Selective colour (absolute checked)

Whites changed to 27 Cyan and 17 Magenta

Click OK to accept and then refine the mask

See this tutorial

http://retouchpro.com/tutorials/?m=show&id=222

 

 

Step 2c)

All that remains is to repair the colour cast.

Add a blank layer and set blending mode to colour

Paint in the green grass and paint white onto the plane

Paint to even out the colour in the runway

Add a little colour to the ladies hair.

 

 

All Done.

 

 

Here is my layers palette

 

 

Many of these methods are useful for any picture with similar faults. It's just a matter of adapting them to suit the particular picture

Remember this tutorial was written using PS7. Later CS versions have shadow highlight and match colour etc which will also be useful

 

I hope you find this useful.

 

Ken.

 


This Tutorial published at http://www.retouchpro.com