Not sure why, but last week I started playing around with the Median Filter and found out it is a pretty nifty Photoshop Filter. It is found by going to Filter -> Noise -> Medium. It works great with other filter or plugin effects and seems to be one of those overlooked older filters that Photoshop packs with its software. Using this filter basically creates an image made of softer shapes with less detail.
The funny little Great Orange Tip Butterfly photo taken at the Rainforest Exhibit at the University of Florida’s Museum used this filter. I did use Topaz Gigapixel (as the image was cropped really tight – see my How to Use Gigapixel AI as a Plug In to Photoshop blog) and Topaz Denoise AI since the crop really showed up any noise in the image. (Topaz website can be found in the sidebar at my Tidbits Blog.) Then I tried out the Medium filter – it actually provided a really interesting beginning background for this image. When set to Multiply blend mode, it gave a really rich feel to the background and made lots of the lines fade into the background. (The other filters used in this image were Corel Painter’s Particle Shop using the Heat Trail filter which gave the pretty string effect and Photoshop’s Spherize filter which really rounded up my butterfly – I will blog on this one soon as it is actually a lot of fun to use also.)
How does this filter work? Heads Up – technical info here – skip if you do not care
The filter is controlled by adjusting the size of the Radius slider which goes from 0 to 600. The following info is from Adobe Photoshop Special Effects Focus Guide from 2003. Amazing this filter is still around and useful. If you set a Radius of 25, the Median filter will select the image using groups of 25 pixels. It blends these pixels together according to the closeness of their color and brightness – any pixels that are too different from the average color in a group of pixels will be discarded.
Adobe says the Median Filter “reduces noise in an image by blending the brightness of pixels within a selection. The filter searches the radius of a pixel selection for pixels of similar brightness, discarding pixels that differ too much from adjacent pixels, and replaces the center pixel with the median brightness value of the searched pixels. This filter is useful for eliminating or reducing the effect of motion on an image.” Yawn!
When would you use this filter?
The filter can be used as an alternative to the Gaussian Blur filter to blur parts of an image to change the depth of field. The result can be more natural-looking similar to a real photograph effect.
At a very low level (like 1 or 2), it has a smoothing effect which can help reduce moire patterns and noise in an image. With scanned images, try setting it to a minimum amount to fill in small white scanning speckles. See my Scanning with a Black Box Blog for more on this.
The filter averages out colors that are too different from those found in the set Radius value. Here is an example of a Radius set very low at 19 and it gives a nice soft depth of field with just the guitar strings sharpened by removing the effect with a layer mask using a brush set to black. This image is one of my favorite images for practicing new techniques from ISO Republic called Guitar Man.
At higher levels, it produces soft, abstract images that still contain fairly distinct edges in contrast areas. This could be used for some very interesting effects.
The Median filters seems to work really well to just soften up any distracting things in the background but does a better job than the Gaussian Blur filter. I will try using this more and decide if it really is better. I tried to soften a waterfall with this filter and use a layer mask so only the water was affected. PS says it works well with motion blur, but I actually found the Motion Blur filter works better for this. (See my Smoothing Those Waterfalls Blog on how to do this.) It would probably be an easy experiment so give it a try. I plan on being a little more sporadic with my blogging for awhile but I will continue blogging. Just not on a very regular schedule. In the meantime, continue working in Photoshop and trying out all the cool things it has…..Digital Lady Syd
This is a Photoshop “oldie but goodie” for making your waterfall images smooth and silky as if you shot it in the shade with a slow shutter speed. I was lucky enough to visit the Big Island in Hawaii recently. Waterfalls are abundant. Unfortunately tripods cannot be used in most cases and sunlight can be very bright when shooting at tourist spots, so the only way to get that smooth silky look is to fix the waterfall in Photoshop. That is what you are seeing in the first two images. The first image original (shown on left below) is the tone-mapped result of three photos processed in NIK HDR Efex Pro before processing in Photoshop. The smoothing steps are as follows:
1. Duplicate layer.
2. Go to Filter -> Blur -> Motion Blur. Turn the angle to the direction of the waterfall, in this case 90 degrees. Set the distance slider to a large amount – for the above it was set to 155, but that may be too much for some images.
3. Add a black layer mask by holding the ALT key and clicking on the Layer Mask icon in the Layers Panel.
4. With a soft brush set to a low opacity like 30% slowly paint in where you want the blur effect on the waterfall.
5. Add a Levels Adjustment Layer to darken the midtones by moving the black and white stops. This image had the black stop set to 5 and white stop to 121.
This lovely waterfall on the road by the golf course (there were several of these man-made waterfalls along this busy road so I had to shoot from the window to get this picture) is similar to the one above but with several small falls going in two different directions. In this case, two Motion Blur filters had to be created to match the water direction. First follow steps 2 through 4 (the first Motion Blur filter layer used settings of a -90 degree angle and 45 distance), create a composite layer (CTRL+ALT+SHIFT+E) on top, and do steps 2 through 4 again (this time a filter setting of -51 degree angle was used). Then finish up with step 5. Nik,s Color Efex Pro recipe Detail + Vignette from Matt Kloskowski was added after applying the steps.
Here are the originals of images as they were processed in Lightroom.
GETTING THAT WATERFALL SHOT IN CAMERA
In case you area not familiar with how to shoot waterfalls, the basic idea is to set up the camera on a tripod in manual mode using a long shutter speed set to 1 or 2 seconds, a small aperture like F/16 or F/22, and low ISO setting. For one of the best discussions on how to compose and shoot a really good waterfall picture, see Craig Tanner from The Mindful Eye podcast “Scenic Waterfall Photography” – this site is full of great photography information.
That’s it – a pretty convincing result is created and it takes just a couple minutes. This is definitely one to store in your arsenal of Photoshop quick tips!…..Digital Lady Syd