Follow this newly discovered method of simulating a polarizing filter with Adobe Photoshop that’s faster, easier, and more effective. Considered the most useful filter in Photography, a polarizing filter makes almost any image look better by absorbing glare to reduce or eliminate reflections and darken skies.
Understanding how this polarizing effect works
Download and save the following JPG file to your computer then open it inside Adobe Photoshop.
vancouver.jpg 204.46 Kb (Right mouse click> Save As)
Once you have the photo opened inside Adobe Photoshop, look inside the Channels pallet (Window> Channels). Inside the Channels pallet, click on the each of the channels and notice the differences between the channels.
So the red channel’s characteristics are similar to those characteristics of a polarizing filter (reduced reflections and darker blue skies & green vegetation), but how do we apply those characteristics to the image? In the next page, we’ll teach you a fast and effective way of simulating a polarizing filter.
Applying the Polarizing Effect
To apply the characteristics of the red channel into the entire image, we need to replace the luminance of the entire image with the image from the red channel.
Open an image you would like to work with or use the vancouver.jpg file we still have opened in Photoshop.
Duplicate the current layer (Layer> Duplicate Layer or Ctrl+J).
Go in to the Channels pallet (Window> Channels) and click to select the Red channel.
With the red channel selected, create a selection of the canvas (Select> All or Ctrl+A) and copy the selection to clipboard (Edit> Copy or Ctrl+C).
Before we paste the red channel into the Lightness channel, we need to convert the image into Lab Color (Image> Mode> Lab Color). When it asks “Changing modes can affect the appearance of layers. Flatten image before mode change?”, select Don’t Flatten.
Go in to the Channels pallet (Window> Channels) and click to select the Lightness channel.
Paste (Ctrl+V) the red channel that you have copied in your clipboard. The Lightness channel should be replaced with the image from the Red channel.
Because we took data from the red channel and used it as the luminance of the image, the lightness of the reds are not correct. We can’t really fix this so what we’re going to do instead is simply mask out the effect from the areas that are red. This causes the effect to only visible on areas that are not red.
Now that we’re done with applying the image from the red channel into the lightness channel, we can change the image mode back to RGB color (Image> Mode> RGB Color). When it asks “Changing modes can affect the appearance of layers. Flatten image before mode change?”, select Don’t Flatten.
Select the top layer and add a layer mask (Layer> Layer Mask> Reveal All). Click on the thumbnail of the layer mask to ensure it has been selected.
With the layer mask selected, use the Apply Image tool (Image> Apply Image) with the following properties:
- Layer: Background
- Channel: Red
- Invert: Checked
- Blending: Multiply
- Opacity: 100%
If you feel that the effect is too strong, you may reduce the opacity of the top layer to adjust the strength of the polarizing effect. To increase the effect, simply duplicate the top layer (Layer> Duplicate Layer or Ctrl+J).
Questions & Answers
- When should I not use this polarizing filter Photoshop effect?
- When should I use this polarizing filter Photoshop effect?
- Why is my photo so grainy?
- What are some methods to reduce noise?
When should I not use this polarizing filter Photoshop effect effect?
There are a few photo situations that may not produce desirable results. These includes:
- grainy photos (usually photos taken with a high ISO speed)
- photos with large amounts of reds
- photos with high contrast and low detail
When should I use this polarizing filter Photoshop effect?
Although taking a photo with a real polarizing filter will produce better results, this Photoshop effect is ideal for photos taken with:
- cameras that do not support filter attachments (ex. compact digital cameras)
- lens that do not support filter attachments (ex. wide angle & fisheye lens)
Why is my photo so grainy?
We recommend using this Photoshop effect on photos taken with a low ISO. When applying this effect, the noise from the red channel gets copied over to the lightness channel. Because most digital cameras produce more noise in the red channel than the green or blue channels, this effect can only produce satisfactory results for images taken with a low ISO.
What are some methods to reduce noise?
If you are working with an grainy photo, we recommend reducing the noise prior to applying the Polarizing Filter Photoshop effect. We recommend using 3rd party noise reducing programs such as Neat Image and Noise Ninja. If those options are not available to you, we recommend:
- for Photoshop CS2users: the Reduce Noise filter (Filter> Noise> Reduce Noise)
- for Photoshop CS or lowerusers: the Despeckle filter (Filter> Noise> Despeckle)