13 April 2009

Tutorial - Instrument Isolation (Funky Worm)

A few weeks ago I posted a video/blog entry showing the results of instrument isolation in Photoshop. Here is a tutorial showing how you can reproduce it.

I. Turning a sound into image
- Cut the piece of sound you want to work on in your favourite audio editor and save it to a file
- Open that file with Photosounder
- Once the image is done loading up on the screen, press the Save button and select "Image file" in the drop-down menu

II. Synth removal
- Open that image file in Photoshop (or similar image editor like GIMP)
- Invert the colours for the sake of visibility (Ctrl+I)
- Select the Clone tool, and set it to a size of 4 pixels, and a hardness about 70%
- Make sure the Aligned box is ticked, hold Alt, click somewhere on the image, release Alt, and click again a dozen pixels right above the point you previous clicked. Also, make sure the Mode is set to Lighten.
- Erase the lowest line that belongs to the synth this way
- Then proceed to erase all the lines above this way. At some point you might choose to have your source above where you spray instead of under, or just make the source closer to where you spray.
- When you're done removing all the synth lines, Invert (Ctrl+I) then Save (Ctrl+S)

III. Listening to the results
- Make sure Photosounder is loaded with the original sound
- Load the image you just edited and saved
- Press the Lossless mode button so that it's ON
- Press Play once the blue progress bar above the image is entirely dark blue

IV. Isolation
- Copy the synth-less image and paste it on a new layer on top of the original image
- Invert both layers (so that their backgrounds are both white)
- Set the image to 16-bit mode
- In Levels set on both their Gamma (the central value) to 2.00
- Set the blending mode to Difference
- Flatten the image
- Invert it
- In Levels set the Gamma to 0.5
- Turn back to 8-bit mode
- Invert again and save the image file
- Reload the image file in Photosounder (press R) and listen

V. Clean up
- Invert
- Clean the noise around the lines with a tiny (about 4 px) white brush
- Fix the holes in straight lines with the clone tool
- Select the highest line which you could fully fix, then copy it and move it upwards in the place of the incomplete lines
- Change the intensity of each copy of the model line with Levels so they fit the intensity of the underlying line
- Flatten
- Invert
- Reload the image in Photosounder
- Save the audio file by pressing Save

If there's any aspect of this that requires clarification do ask about it in the comments.

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©2008-2009 Michel Rouzic