using blend darken to eliminate white items

[trevorc]

I think I have seen how to do this but I can't work it out.  Can anybody point me at a tutorial that shows me how to do it.

I have a picture with a main subject and a predominantly black background.  Scattered around the main subject often in places difficult to access is lots of pieces of white fluff.  I have created a second totally black layer using new fill layer  (is that relevant, would a new layer that I had painted black be any different).  I think that I should be able to blend these two layers (using darken or lighten) in a way that that the dark layer will override the white fluff and not affect my main subject providing that also doesn't have strong white areas or providing I can mask it effectively.  I have tried various options but I am not covering the white bits, any advice or as I say a link to a tutorial would be appreciated.

[Tirami]

Try using the blend ranges tool by clicking the gear icon right next to the blending options in the layer dialog, then play around with the underlying composition ranges.The right side of that box represents highlights, the left side represents shadows. The problem with your whole method and this method as well, is that it will darken anything within the same tonal range as the white specks, e.g. the highlights on the bug, and even if you could isolate the white specks, it would fill the specs with a solid color, which doesn't seem natural with the background, so what you can also do is use the inpainting and blemish removal tool to eliminate the specks. Here's a picture of what the first method results in and a picture of the second method (I was unsure if you wanted to remove the big white circles at the top and also did a really quick job of it, if you take your time, I'm sure it'll look great!):

 

The first method could be used to isolate the specks and then you could probably do a ton of other things, but the white specks are quite visible as already is in the photo, so I'm still against the first method.

Edited May 11, 2020 by Tirami

[firstdefence]

There isn’t really a fast track way to get rid of the crud, a bit of time spent using the inpainting tool and the blemish removal tool will get you some like this...

[smadell]

firstdefence answered while I was working, and that's a good result – labor intensive! As he's said, this is not the trivial problem it appears it should be. Here's what I did.

I selected the bug (use the Selection brush and Refine Selection…). I copied that onto a new layer. Then I applied a Gaussian Blur (live filter) and a Levels adjustment to the background. That has the effect of smoothing out the speckles and darkening up the background a bit. The bug stays intact, since it's in a separate layer above. (And yes, I know that the speckles under the bug are still showing. Judicious use of a mask on the Bug Only layer could get rid of that easily. I just didn't take the time!)

[trevorc]

ThanksTirami, first defence, smadell.  Some interesting ideas for me to play with.  I have been using blemish removal and inpainting as part of a solution and got some credible results but it does take a long time.