Cleaning up overall dirt, grunge, smoke residue

[juliewood]

Can anyone suggest a tip for cleaning up the sort of overall-but-patchy dirt and grunge you may see on the surface of an old photo? I'm not referring to defined stains or marks, but the uneven brownish-yellowish cast they acquire (especially in the home of a cigarette smoker). It is surface dirt as opposed to paper-yellowing. I have attached one example, as the full photo, a closeup of one area, and the same closeup with levels tweaked to try to better illustrate what I mean. (I'm not referring to the distinct brown marks or the texture, those I can handle.)

Doing a color cast correction doesn't work well because the dirt is blotchy (and the closer I get the whole photo to a neutral white balance, the more obvious the dirt seems to get.) The difference in color is too subtle to make a color-range-based selection, and a luminosity or channel-based selection gives me trouble because the dirty lighter tones are equal to the clean midtones. (I am using photoshop CS5.)

For this photo I ended up doing several layers of "quick degrunge" at different intensities and then some layers in color blend mode, but I wasn't really happy with the results because the degrunge kept taking out too much of the folds in the dress and the recoloring looked fake. The client loved it, but I feel like I was missing some obvious solution.

This seems like something that would be covered here before but I'm clearly not thinking of the right keywords to find the relevant threads. (Though I've really enjoyed reading all the non-relevant search results!) If anyone can point me in the right direction I would really appreciate it.

Thank you!!!
Julie

[mistermonday]

Hi Julie,
My tendency would be to first do a high level correction for color balance and tone. I would then suggest using frequency separation which will give you a layer of color and another layer of texture. You can fix up the color on the low frequency layer and you can clone away the spots and scratches on the high frequency layer. I started the process and after 5 minutes stopped here.
Regards, Murray

[juliewood]

Murray, thank you so much for pointing me in the right direction. Reading the threads on frequency separation, I think you have just opened the door to a very valuable tool for me! I really appreciate it. I didn't find anything about a "high level correction" technique - by that did you mean a global, "first-step" type correction or was there something more specific you were referring to?

Thanks again!!

[mistermonday]

Julie,
Yes, a global correction. You can try Image>Auto Color or make a curve adjustment setting a white and black point, or a Level adj to compress the R,G,&B channels individually. Basically you want to get the color and contrast of the image within range of what the orig scene looked like.
There are actually two types of frequency separation. the standard one about which you have been reading and another I call Asymetric, which completely isolates color and texture. I did not try the standard one on this image and it may work very well but I did use the asymetric one, and it worked very well. I was able to paint over the whole dress which cleaned up a lot of the stains.
I have attached a zip file. It is a PS action which performs both type of separation. The standard one is 1st and the asymetric one is below it, labelled Freq Sep (Luminosity). If you use the Asymetric one I recommend that the 1st thing you do after running the action is to merge together the monochrome LF and Color LF layers so that you have only one LF layer.
Good luck with the restoration.
Regards, Murray

[chillin]

I would firs start with an FFT filter.

[Flora]

Originally Posted by juliewood

Can anyone suggest a tip for cleaning up the sort of overall-but-patchy dirt and grunge you may see on the surface of an old photo? I'm not referring to defined stains or marks, but the uneven brownish-yellowish cast they acquire (especially in the home of a cigarette smoker). It is surface dirt as opposed to paper-yellowing. I have attached one example, as the full photo, a closeup of one area, and the same closeup with levels tweaked to try to better illustrate what I mean. (I'm not referring to the distinct brown marks or the texture, those I can handle.)Julie

You got great tips already, but I had already started to work on your dirt-2.jpg picture so I post my results anyway: for "cleaning up the worst of overall-but-patchy dirt and grunge" I used Image>Apply Image

SNAP-057.jpg

• For minimizing texture without losing 'too much of the folds in the dress' like chillin I used the FFT Filter + Neat Image
  
• For Clean up spots etc. like Murray I used the Frequency Separation
  
• For adjusting the Colour I a used Hue/Saturation Adjustment Layer.

SNAP-058.jpg

P.S. Murray, after having run your action, I realized that what you call Asymetric Frequency Separation .... I call Saturation Frequency Separation or Sat-Frequency-Separation which I used here The only real difference that noticed between our 'techniques' is the fact that in the Apply Image Dialog Box we use different Blending and therefore values:
You use: Invert>Add
I use Subtract ...
But I couldn't see any difference in the result.

SNAP-059.jpg

Could you, please try my Sat-Frequency-Separation action and let me know?

Thank you in advance!!

[mistermonday]

Hi Flora,
There are two variations to the Apply Image command in creating a Freq Sep. If the image is in 8 bit, the process uses Image>Apply Image Subtract Mode, Offset =128, Scale=2. However if the image is 16 bit, the process is Image>Apply Image ADD Mode, Offset = 0, scale = 2.
The best thread that you will find to explain the why this is the best way to create a High Pass layer and why the High Pass filter in PS is flawed, can be found here at Model Mayhem. The thread is gruesomely long BUT the essentials of what it is about and the summary of the process is all on the 1st page.
http://www.modelmayhem.com/po.php?th...=439098&page=1
The bulk of the thread deals with the standard Frequency Separation (GB+HP=Orig Image) which is also to say (LF+HF=Orig Image). For most retouching, this is probably all you need. The concept of completely separating Color and Texture may be discussed toward the end of the thread but there is a good discussion that continued here at RP and I will look through the archives to try and find it for you. In the meantime I would highly recommend you take a look at the MM thread, or at least the 1st page.
Best regards, Murray

[juliewood]

You are all amazing... thank you all so much for the wonderful advice!!

[unimatrix001]

I switched to lab color mode. used the median filter on the lightness channel, to remove the texture boosted the colors and used a cooling filter to tone down the colors. then sharpened using unsharp mask filter.

[Flora]

juliewood,

thank you so much for your feedback and kindness!!!


unimatrix001,

Originally Posted by unimatrix001

I switched to lab color mode. used the median filter on the lightness channel, to remove the texture....

Thanks for the tip! I never thought of using that technique. Unfortunately, when used at higher Radius, (sometimes necessary) it tends to blur a bit too much, so, I still wouldn't use it on portraits for which I would still go for the more accurate FFT Filter ...

SNAP-064.jpg

But it is a great help for minimizing the worst scartches in non 'vital' parts of some images!

SNAP-065.jpg

Murray,

thank you so much for the link and explanations about the 8 bits and 16 bits difference in Frequency Separation! ... Since the technique is incredibly useful, but not always very easy to 'grasp' ... at least for 'newbies' .. I would like to prepare, with your help, a basic mini tutorial about it...

[mistermonday]

Hi Flora, sounds like a good plan. Count me in.
Cheers, Murray

[unimatrix001]

Flora I do agree with you but in this instance it seemed to work very well. I dont use it on all examples of repeating patterns just the ones it works on with a radius of 1. You are welcome for the tip.

[Cupcake]

Here is my try.