Laura revisited

Besides the run-the-detail-sliders-down-to-zero version, RAW Therapee has three other ways to reduce noise.  The one I find most interesting is the third one down on the details tab.  It has  two sliders to control how much luminous and chromatic noise is removed .

It also has a third slider labeled gamma. That is actually a gradient filter. It cuts down the noise reduction--and loss of detail--in the bright areas of the image where it is not needed much, but it still applies strong noise reduction to the dark areas where it is really needed.

A very neat effect. Off and on screen shots below. Notice how it balances the noise from the black background with almost no loss of detail in Laura's hair

Who is Laura and why is she being revisited? A Young Shakespeare Player who I blogged about earlier. See fun-with-imagej,  November 2009

Enhanced Detail

Yesterday  the Madison Flickr Meeters went to the dome of the Olbrich Gardens in search of macro images. I started off with  my 18-105mm kit lens mounted to the D7000. It's more of a closeup lens than a macro lens so I also packed up several other lens I planned to check out.

One problem I hadn't considered propped up immediately. The humidity in dome was 100% Tropical Rain Forest; my camera and lenses which had been sitting in the car were cooled down to 100% Madison Winter Frigid. Instant condensation.

Continually wiping off the filter on top of the lens was an annoyance but not a major problem. Doing the same thing to the sensor would have been a disaster. So the lens stayed on. No real macro images but some decent flower closeup.

Contrast Disabled

 Contrast enabled

Which became even more decent when I used the RAW Therapee features I blogged about yesterday.  If you do macro photography RAW Therapee is worth looking at just for Richardson-Lucy deconvolution. (There has to be a better name than "Contrast by Detail Layers.")

Am I about to toss out Photoshop? No. I shot with an off-camera flash but in this image there were a few small areas that reflected the flash straight into the camera and created annoying hot spots. So I imported the jpeg into PS and used the healing brush to clean up the image. Can't have everything in a RAW converter.

Edit-When I posted the image on flickr and viewed the black box original I saw that the image looked noisy. Setting the fine slider to 2.2 did a SUPER GREAT job of bringing out and amplifying  the noise in the image! Setting it to zero cleaned the image up. Something to remember if you use the feature.

Smiling Girls-With a Dash of RAW Therapee

I could have converted this underexposed color image into a correctly exposed B&W image using Adobe Camera RAW and Photoshop but it would have been a multi step process.  After I converted the RAW data into a RGB image I would have had to imported it into Photoshop, converted it into a LAB image and then used a curve or level layer on the L channel to adjust the exposure. With RAW Therapee all than can be done in one simple step.

When I first started out I thought, like I suspect most user do, that Photoshop did its mathematical calculations in the  RGB mode. But it starts out in the LAB mode. Instead of the familiar Red, Green and Blue channels LAB has, not surprising,  L, A and B channels. The L or Luminosity channel has all the black and white picture information.  The A channel has all the red and green color information. And the B channel has all the blue and yellow color information,

A major and practical advantage of this mode is you can apply a curve layer to the L channel and do what you want without touching the color information and introducing a color cast.  You can also do the same thing to the A and B channels to correct a color cast.  Or you can go hog wild and create colors that nature never intended.

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Besides LAB curves there are several other things I like abut the exposure tab in RT. If you click on the + sign on the bottom you can pull up multiple viewing boxes. When I processed the image I monitored  the eyes of the two girl, the shirt and the writing on the folder as I adjust the L channel. I've also ran the saturation down to zero for B&W. If I had wanted to change the intensities of the the various colors I could have adjusted the A&B channel. Or I could have gone to the color tab and used RT's channel mixer. There are often several ways to adjust a RAW image in RT.

(With more to come. Yesterday I saw postings about a new tone matching feature for HDR work on RAW data)

In Lab curves you can pull the the usual spot and parametric adjustments but I prefer using the control cage adjustment. This uses tangential  Belzer controls.  You don't have annoying dips at one end of a curve adjustment when you raise the other end. You also have a well designed histogram window up at the top where you need it instead having to call up a separate window.

A second feature you won't find anywhere except pricey astrophotography programs is Richardson-Lucy deconvolution. This algorithm was developed by NASA to deconvolute or enhance the images from the Hubble telescope. 

Enhances  Contrast Off