Correction of a Dark Photo: Layerwise Removal of Noise
 

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Tutorial: AKVIS Noise Buster

Layerwise removal of noise

 

Jean-Claude Grégoire offers us a tutorial on how to improve a photo with uneven exposure.

Before and after
Before and After
Click on an image to view a larger version in a separate window

The original photo was too dark. After it was processed with the AKVIS Enhancer plugin, the photo was brighter and more details were visible. However, noise in the darker areas of the picture became much more noticeable.

It's now necessary to reduce this noise.

    Noise in the dark areas
  • Step 1. There are several ways of doing it, e.g. with the Photoshop's Noise Filters (see "Appendix" below). But I've found an easier and better way: the AKVIS Noise Buster plug-in. So I call the AKVIS Noise Buster plug-in (main menu: choose "Filter > AKVIS > Noise Buster").
  • Step 2. I start with trying the automatic filtering by clicking on the button Automatic Filtering.

      Note: In the current version just select the preset "Auto Filtering".

    Automatic filtering

    I immediately see that the noise isn't reduced enough in the preview area (square selection in the middle of the AKVIS window).

    Automatic filtering in the preview area

    But if I move the red square in the small window (left click and drag) and the preview area in the main one ("click-and-drag" too), I can see that the correction is excellent in the window that looks onto the garden

    Autofiltration result in the light areas

    but not on the woman's head.

    Autofiltration result in the dark areas

    If I play with the Smooth Level slider under Luminance Noise and slide it to maximum, I see that the image remains excellent on the garden and is already better, but not yet perfect, on the woman's head.

    Increase Smooth Level

    Here I have to put the "Noise Level" slider to 100% to get a good image, but then the garden becomes too blurred.

    Adjust the parameters

    The conclusion is that it isn't possible to get a good correction for the whole image in only one step.

  • Step 3. Thus I decide to begin with the Automatic Filtering of the whole image, by clicking again on the Automatic Filtering button, and then successively on the "Run" and the "Apply" buttons.
  • Step 4. I examine the result and find that it's only necessary to rework on some areas of the image:
    those which still have too much noise. Therefore I need to isolate them from the others, so that I can work on them separately.

    For isolating the good and the bad parts of the image, I'll begin with selecting the good areas (i.e. the lightest ones). The easiest way to proceed is editing the image in Quick Mask Mode by clicking on the button Edit in Quick Mask.

    Switsch to Quick Mask mode
  • Step 5. I open a new window ("Quick Mask Options") where I choose the way the mask will work: "Selected Areas" and the opacity 100%. Here I've clicked in the color square for getting the color "RGB 255-0-255" (it's always a good idea to change this color for one which contrasts very much with the overall tonality of the picture).
    Quick Mask Options
  • Step 6. I feel that the lighter areas are easier to select and I paint them over with the pencil and the brush tools - but it can be the opposite with other pictures.
    Paint over the light parts
  • Step 7. I click on the Edit in Standard Mode button on the left of the Quick Mask Mode and I save the selection (main menu: Select > Save Selection or the shortcut Alt+S+S), giving it an evocative name, e.g. "light areas".
    Switsch to Standard mode
  • Step 8. As I need a selection of the darker areas of the photo, I press Ctrl+Shift+I for inverting the selection and I save it with an evocative name: "dark areas".
  • Step 9. I once again click on the Quick Mask Mode Button and get the mask you can see on the photo below. So I can return to the Standard Mode again for the next step.
    A mask for the dark areas
  • Step 10. I don't quit the selection and press Ctrl+J on the keyboard. This action makes a copy of the image, limited to the selection, on a new layer. I name this new layer "dark areas".
    Dark areas layer
  • Step 11. I activate this "dark areas" layer and I call the AKVIS Noise Buster plug-in again. I press the button Automatic Filtering and then play with the sliders until I find good settings for the painting on the wall, above the woman's head.
    Noise reduction
  • Step 12. Then I successively click on both Run and Apply buttons as in step 7 above.

    The result is better for the bad parts of the image in general and has not affected the garden and other good parts of the image

    Noise reduction in the dark areas

    But if I zoom on this image, I see that the darker areas are not yet corrected enough: there are still some "clouds" left, which are particularly visible on the woman's head.

    Noise reduction in the dark areas
  • Step 13. So I make a new selection of these darker areas in Quick Mask Mode - with the brush and the pencil tools - and I save it under another name, e.g. "dark areas #2".
    Select the darkest areas
  • Step 14. I don't quit the selection, activate the corrected layer "dark areas" and press Ctrl+J on the keyboard. This action makes a copy of the darker areas of the image, limited to the selection, on a new layer, which I call "worst areas" .
    The layer with the darkest areas
  • Step 15. I activate this "worst areas" layer and I call the AKVIS Noise Buster plug-in once again. I select Automatic Filtering and then play with the sliders until I find good settings for the head of the woman.
    Noise reduction on the dark parts of the photo

    Then I successively click on both Run and Apply buttons, etc. (as described in step 7, above). The "clouds" in the darker areas have come out.

  • Step 16. I activate all the layers again and can see that the result is very good.
    Noise reduction result
  • Step 17. I flatten the image and save it. Maybe it's not a "chef d'oeuvre", but nevertheless it's a very good picture!
    The corrected photo
  • Step 18. Now I can print it on very good Glossy Picture Paper for inkjet prints - the printed image size is 6.227 * 4.267 inches or 15.82 * 10.84 cm. If I print the image on the same paper before the application of the AKVIS Noise Buster plug-in, I clearly see the difference (to see the difference better, save this picture on your hard disk, then look at it in a very dark room).
    The image before and after the noise correction
    Before Noise Buster and After Noise Buster
    Click on an image to view a larger version in a separate window
  • Step 19. Fig. shows the difference before and after processing - as described above - with the AKVIS Enhancer and the AKVIS Noise Buster plug-ins.
    The image before and after correction
    Original Photo and Result (After Enhancer + Noise Buster)
    Click on an image to view a larger version in a separate window

 

Appendix

Before getting the AKVIS Noise Buster plug-in, I had tried to get rid of the noise I got on step 3 above, with the help of the Photoshop noise filters alone. I'd got the best results by applying successively the filter Noise > Median on both layers "dark areas" and "worst areas", with the Radius "4 pixels" and "12 pixels" respectively.

Fig. 32 is a zoom which clearly shows that I've got a better result with the AKVIS Noise Buster plug-in, which is easier to work with, than with the Photoshop's noise filters (Photoshop's Median on the left side, Noise Buster on the right one).

Noise reduction with Median filter and Noise Buster
Noise reduction with Photoshop Median filter and AKVIS Noise Buster
Click on an image to view a larger version in a separate window

 

 
How It Works How It Works
   — Workspace — Workspace
   — Using the Program — Using the Program
   — Effect Parameters — Effect Parameters
   — Batch Processing — Batch Processing
   — Preferences — Preferences
Examples Examples
   — Cover Girl — Cover Girl
   — Remove Moire on Scans — Remove Moire on Scans
   — Reduce Noise on a Studio Photo — Reduce Noise on a Studio Photo
   — Color Noise Suppression — Color Noise Suppression
   — ISO and Noise — ISO and Noise
   — Suppress Noise on a Rendered Image — Suppress Noise on a Rendered Image
   — Noise Reduction on a Corrected Photo — Noise Reduction on a Corrected Photo
   — Improve a Dark Photo + Remove Noise — Improve a Dark Photo + Remove Noise
   — Make Your Photo Look Better — Make Your Photo Look Better
   — Remove JPEG-Artifacts — Remove JPEG-Artifacts
   — Lightening Dark Photos — Lightening Dark Photos

 

Noise Buster v. 10.2 - Free 10-day Trial    Download

 

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