Removing Cracks in Photograph Using Layer Mask

[Celebral]

Hi

I am trying to restore an old photograph covered in cracks and speckles. I came across an excellent tutorial here: http://robertb.smugmug.com/gallery/6927932_PSYHM and many references to Tim Edwards' "Quick Decrack", which seems to run along similar lines, which is how I found myself here!

I am using Photoshop CS6 and so "Quick Decrack" will not work with this version. I was hoping someone could review the steps below (or you can follow the full tutorial at the link above) and tell me what I am doing wrong in the end!

Hopefully this will be useful to someone else in the future:

STEP 1
Duplicate background and then apply to this layer FILTER/OTHER/MINIMUM
Now apply FILTER/OTHER/MAXIMUM
Now rightclick over layer and change blending options from "normal" to "difference"
Press Alt-Ctrl-Shift-E to create a merged copy of this layer

STEP 2
Make another duplicate background layer (i.e.. another copy of the original image)
Now apply FILTER/BLUR/GAUSSIAN and blur until no speckles etc are visible

STEP 3
OK so far so good we now have 4 layers, namely:

Background (your original image)
Duplicate Background 1 (we applied the min and max filters to)
Merged layer (created when we pressed Alt-Ctrl-Shift-E)
Duplicate Background 2 (the blurred one!)

So now we select the merged layer to make active and press Ctrl+a (to select all) and Ctrl+c (to copy all to the clipboard)
Now we select Duplicate Background 2 and add a layer mask. Once added hold alt and click the layer mask icon in the layers palette (the image will appear as plain white) now press Ctrl-V to paste the merged layer into the layer mask.

STEP 4
OK so now I have a layer mask containing every speck and scratch I want to remove (really is amazing!!!) and a blurred image containing the colours I want to use to replace all those specks and scratches with. BUT I DO NOT KNOW WHAT TO DO NEXT?

Please can someone assist and tell me how to apply the mask so that the lighter areas are replaced with pixels from the blurred image.

Thanks very much, if someone has ever created a step by step guide to applying Tim Edwards method manually then please direct me to this to, as I would like to give his method a go also. Finally, to remove darker specks and scratches from an image, you reverse the application of the min and max filters in step one above.

[genf]

Re: Removing Cracks in Photograph Using Layer Mask

It seems that you are missing one step indeed.

Have another look at the mask you created in step 3. It should be white where scratches must be removed, black elsewhere. Instead it is either black or very dark grey. Consequently, the layer will have a very limited effect.

Now do the following. Make all layers invisible except the background and duplicate background 2. Click the mask (not alt-click because you want to see the image changing while applying the following step).
Click Image - Adjustments - Threshold. Pick the slider in the middle and move it leftwards. Keep an eye on your image. At some point you will see the scratches disappear. Click OK to confirm when you found the optimal threshold value.

To see what you just did, alt-click the mask. It has become far more effective.

[Celebral]

Re: Removing Cracks in Photograph Using Layer Mask

Thanks very much for your reply. I followed your helpful instructions and the mask definitely worked better.

Unfortunately the results were not as good as i hoped, but that may well be my unrealistic expectations! Essentially it just seems to leave you with a different, more unnatural mess to tidy up.

I attach a before and after image of part of the image together with the layers I ended up with in photoshop in case I have missed something else.

[Tony W]

Re: Removing Cracks in Photograph Using Layer Mask

Your expectations may be too high but I think that you should be able to improve on this first effort with a little luck and patience. But remember that this technique is only trying to remove the white spots.

You may also be capturing the print texture and stains which will have to be dealt with seperately.

You have missed adding a levels layer (this should be created as a clipping layer). Experiment with bringing the black point slider in towards the right as well as the mid point slider adjustments - stop before the white spots go black.

Your mask should be adjusted so that you have got the spots/dust as bright as possible and the blacks a true black.

Quick attachment showing how the mask should look and the missing levels layer. Also attached using your posted original and a comparison.

Although the difference slight it is noticeable and I am betting that working on your original scan you will improve much on my effort on a small jpeg.

EDIT: BTW Quick Decrack will work in CS6

[Celebral]

Re: Removing Cracks in Photograph Using Layer Mask

Thanks for your email and attachments. I can see it is definitely worth some more trial and error and the addition of a levels layer certainly gives more control.

Another problem, is that the more I use Photoshop the more I feel I have barely scratched the surface, at least this exercise has woken me up to some of the possibilities out there.

I will give Quick Decrack another go also

[Flashtones]

Re: Removing Cracks in Photograph Using Layer Mask

I made a dupe layer, ran Dust and Scratches (Radius=4, Threshold=4) and set that layer to darken mode.