Advice for attacking wide-spread mold?

[tropicmom]

Hello!

First time here! I've been learning some restoration techniques the last year or so but I've come across some photos that have me stumped. We had flooding with a hurricane here and a friend has photos that she's asked me to help with. Several of them have this very fine mold pretty much all over the photo.

I've tried Dust & Scratches but it's so wide-spread I couldn't get anything acceptable with that. I stumbled across a video about using the Color Replacement brush which seemed like a fix at first but quickly became problematic.

So what is the best way to approach this? Any advice please?

Thank you!

[skoobey]

Re: Advice for attacking wide-spread mold?

moldsample.jpg

I don't know if this is helpful, but I used the green channel set to darken blending mode, 27% opacity (channel mixer, every channel set to green 100, rest 0), then made a curve to bring back the overall luminosity, then I have desaturated the reds using the hue/saturation adjustment.

[Damo77]

Re: Advice for attacking wide-spread mold?

Do you have a version without so much aggressive jpeg compression damage?

[mikemorrell]

Re: Advice for attacking wide-spread mold?

I'm a relative newbie to restoration and I've never tackled mold stains as wide-spread as this. Good advice from Skoobey on finding the channel, color saturation and tone levels that show the least amount of damage. Color balance might help too. For B&W photos, the B&W Filter filters are useful for filtering out colors that show the most damage.

Tackling mold in larger surface areas of the photo that have pretty much the same tone/color is different to tackling mold in fine details like hair, eyes, etc. For the larger areas, I usually just paint over them in a new layer with the base color/tone. I prefer 'painting' because it gives me good control over the color/tone (with curves/H&S) and transparency (brushes, color layer and any tied color/tone adjustment layers). An alternative would be to use a median filter over the area.

For the fine details that are damaged, I can't see any alternative to patching, cloning, copying and transforming from undamaged details, etc. But these are often relatively small parts of the photo as a whole. Where you can clone or patch cleaned-up details, to other areas of the photo, this saves time.

I doubt whether this is relevant but I watched an interesting video on 'frequency separation' at https://www.youtube.com/watch?v=ldhG9fmgC7o. It's a way of separating 'colors' and 'structure' into two separate layers so that you can work on each independently. The mold stains will show up in both layers. In the 'structure' layer, you can paint over the unwanted details (mold stains) in grey. On the colour layer you can blur, patch, clone or apply gaussian or median filters without destroying the 'structural details' you want to keep (which are in the other layer). This is probably an overkill for removing stains but it's something to be aware of.

Hope this helps,

Mike

[tropicmom]

Re: Advice for attacking wide-spread mold?

Do you have a version without so much aggressive jpeg compression damage?

Most likely yes :-) I scanned it myself and have the scan. I was having trouble getting it small enough to attach to my message and that's what I ended up with above.

I will try the suggestions here, as I'm looking to learn the methods for myself but I'd be happy to provide a better sample if anyone wants to have a try and tell me if they have a method that works!

[flowbox]

Re: Advice for attacking wide-spread mold?

You can restore the photo to the original colors but you need better resolution image

[tropicmom]

Re: Advice for attacking wide-spread mold?

You can restore the photo to the original colors but you need better resolution image

I have a better resolution scan of the photo itself, this was just a sample to show how wide-spread the mold is. What method(s) can be used to restore the original colors?

[tropicmom]

Re: Advice for attacking wide-spread mold?

I'm a relative newbie to restoration and I've never tackled mold stains as wide-spread as this. Good advice from Skoobey on finding the channel, color saturation and tone levels that show the least amount of damage. Color balance might help too. For B&W photos, the B&W Filter filters are useful for filtering out colors that show the most damage.

Thanks, Mike, lots of good points in your post (tho I don't know how to quote just a few parts <g>). Predictably, the green channel is the best, but I confess I'm stumped as to how to use that info to handle the mold AND keep it in color.

I've found painting as you've described helpful on a lot of the background, but particularly both their hair has very few areas clean to clone from, so that'll take some trial and error. (Probably lots of error!)

I recently tried frequency separation as well and I may give that a shot just to see what happens!

thanks again!

[flowbox]

Re: Advice for attacking wide-spread mold?

I have a better resolution scan of the photo itself, this was just a sample to show how wide-spread the mold is. What method(s) can be used to restore the original colors?

You can minimize the red on the picture, restore the damaged parts and you can use the frequency separation (i use the Calvin Hollywood method) to restore the originals colors

[skoobey]

Re: Advice for attacking wide-spread mold?

First you restore luminosity and color using information that you have, then you go into local adjustments. All of the things mentioned can help you.

[John Wheeler]

Re: Advice for attacking wide-spread mold?

I have a better resolution scan of the photo itself, this was just a sample to show how wide-spread the mold is. What method(s) can be used to restore the original colors?

Hi tropicmom

Lots of good suggestions already in this thread.

I usually tackle these problems by fixing the luminosity and subsequently the color. This can be done by a variety of techniques yet hard to recommend a technique as it often depends on the characteristics of the image itself.

Without further information I would start with fixing the luminosity by using the channel mixer adjustment layer set to monochrome and use the sliders to null out the mold luminosity issue. Then I paint back in the correct colors on an additional Layer either based on the original image or starting from scratch with the blend mode set to color.

The reason that starting with a much better copy (preferably a TiFF scan at higher bit depth) is the the JPEG you provided while the luminosity component is not compressed to much, the hue and saturation components are heavily compressed as seen by the pixelation. Makes testing your image for the best recommendation problematic. If you post a much better starting image (even if partial image), there are possible even easier techniques that could work.

The image below shows the original image, and below the luminosity, then the hue, and then the saturation components of your image:

[skoobey]

Re: Advice for attacking wide-spread mold?

Hi tropicmom
The image below shows the original image, and below the luminosity, then the hue, and then the saturation components of your image:

Out of curiosity, how do you get to saturation and HUE previews? Through selective color and solar curves, or?

EDIT: (I'm suffering from Madonna syndrome with my spelling apparently).

[John Wheeler]

Re: Advice for attacking wide-spread mold?

Out of curiosity, how do you get to saturation and HUE previews? Through selective color and solar curves, or?

I use Layer Blending Math to create these previews.

I have seen many approaches to this or similar (e.g. using the RGB>HSB filter is close)

First note that the "Luminosity, Hue, and Sat" trio, the "Sat" component that I use is the one the Photoshop defines in the Saturation Blend modes. The reason I bring this up is that a different definition of "Sat" is used in the HSB of the Color Picker.

For Luminosity, I just take the image, place a constant tone Layer above (e.g. white) and set the Blend to Color.

For Hue, (which is defined by the relation ship of the two largest numbers of the trio RGB), while keeping the Hue constant, I scale the RGB values for maximum Brightness (largest RGB value at 255), and also maximum saturation (Minimum RGB value set to 0)

For Saturation, (defined by the numerical separation between the largest and smallest value in the RGB trio), I create a gray level R=G=B that represents that same numerical separation.

What is nice about this approach is that I can take these 3 components and recombine them through blending to create the original image (within rounding error).

I found it very useful in a variety of situations. Just one of those is showing how JPEG (and other compression algorithms) hide their compression by avoiding compressing the luminosity channel (the eye has high acuity there) and when compression Hue/Sat it does more in the dark and very light areas first. What JPEG does is much more complex yet this shows the impact in terms easiest understood in color terms which we use everyday in Photoshop.

I am not sure my description helps yet that is the high level description.

[JoReam]

Re: Advice for attacking wide-spread mold?

Hi
John I am interested in your approach – so I had a go at trying it out because I wanted to understand how you got your different layers. I managed to generate the Luminosity and Hue layers. And I think I got them right, that is:-
For the luminosity layer, I made a white layer and set the blend mode to colour and blended it with the original.
For the Hue layer, I took a Hue and Saturation adjustment layer with Hue set to maximum and blended with the original. (Is that correct? It does not look as bright as yours so I am not sure I got this correct).
But I could not get the Saturation layer. I am assuming you are using a 50% grey layer and blending it with the original somehow but I cannot work out what the blending mode is to generate your result. My screenshot shows a saturation blend – is that correct? Thanks.

[John Wheeler]

Re: Advice for attacking wide-spread mold?

Hi Jo

You have the Luminosity approach correct yet not the Hue and Saturation.

I took a different approach. I went to the definitions given by Photoshop and then used basic Photoshop math to duplicate what was in the Photoshop reference.

Here is a link toa 756 page Adobe document that covers quite a few topics. There is a section on blend math and part of that includes luminosity, hue, and saturation (it gives you the exact detailed equations used).

The blend math starts on page 324 in section 11.3.5. The Luminosity, Hue, and Saturation section begins in the middle of page 334.

Blends let you add, subtract, multiply, and divide and Channel Mixer Adjustment Layers let you isolate/separate specific channel values for R, G, and B when that is needed by the formulas.

So I started by implementing the exact equations using basic operations as mentioned above. This was for academic purposes.

Now, there are simpler implementations as opposed to the basic detailed math approaches I used yet that has been done by others.

So I suggest if you are really want dig in to all of this, start with the reference and go from there: http://wwwimages.adobe.com/content/d...32000_2008.pdf

Hope his helps you bootstrap up the learning curve.