IHP – Inverted High Pass
I use the high pass filter for more than just sharpening.
In the process of retouching an image there are a lot of steps and this is not. This can not be the first one, this is just another step in the process.
IHP is something like an automatic (not as detailed and not as undestructive) way of getting tight skin and evening out the hard transitions between shadow and light, among other things, while keeping the texture intact.
What we do is retain a certain defined frequency using the high pass, blurred (for the same reason we use a soft edged brush when Dodging and burning) , inverted (to get the negative of the details light/shadow) and blended using the linear light blending mode.
This blending mode burns or dodges by decreasing or increasing the brightness, depending on the blend tone. If the blend tone is lighter than 50% gray, the image is lightened by increasing the brightness. If the blend color is darker than 50% gray, the image is darkened by decreasing the brightness. Very much like D&B with a 50% gray layer, that’s why I call this automatic D&B
Saving time is one of the mayor advantages of this technique
• Smoothing transitions between shadow and light
• Removing Strong Highlights
• Removing strong shadows
• Flattening light – so you can introduce new highlights and also shadows by manual D&B
• Smoothing median texture
• Straightening and tightening fabrics in clothing and accessories.
• Smoothing floors, carpets, grass and any kind of textured surrounding (as long as there’s no recognizable pattern)
• Straightening hair
• Removing blotches in legs and body
Experiment with it, and will lead to a lot of other uses.
• Make a stamp
• Find the problematic area
I found that visualizing the problem can be done using the “preview window” in the Gaussian blur filter. Simply move the slider until the problem area blends with the surrounding area. Take a mental note of that radius but make sure to chose a number that is divisible by 3 (i.e.: If the right radius is 26 then go up to 30, always round up, never down) – Once you have decided on the radius, cancel the Gblur. This is just to visualize the radius in a simple and intuitive way.
• Working on the stamp layer, go to Image/Adjustment/Brightness-Contrast and reduce the contrast to -50 making sure to tick the “Use Legacy” box.
This will reduce the contrast, making it look faded. But in itself will not reduce the effect.
• Still working on the stamp layer go to Filters/Other/High Pass and insert the chosen radius (on the second step)
• Invert the stamp layer
• Run Gaussian Blur filter at 1/3 of the HP radius
• Blend it using the linear light blending mode
• Add a Mask to hide / Paint back where need it, using a big soft brush – 50 to 100% opacity (If you chose the radius correctly, 100% will be perfect)
Notes - Recommendations:
• Using a small radius to work on fine texture is highly not recommended.
• Do not use hard brushes. Do not work over edges (mouth, nose, borders)
• This technique is like drinking, a little bit is fine, but if you go overboard you end up throwing up in a corner; and that’s not attractive.