Wednesday, November 5, 2014

Using the B&W 'before' tools

There is a discussion  in the RT  forum about how to use the before and after curves in the b&w tool. My experience is that to set the color tonality you should make all needed adjustments before the B&W conversion.  Or to be specific when I convert  this candid shot to b&w how bright or how dark should I make the tones of the child's red dress and hair scarf

The b&w image using the default settings. I find it to be a bit washed out and 'blahh'

To make the child stand out from her father I lightened the red using the white balance tool, Or more accurately the white 'non balance' tool. I moved the temperature. tint and  r&b equalizer up until I had a red dress tonality much lighter than her father's shirt. Unfortunately the histogram is now too far to the right

To fix that problem I used a 'before' parameter curve.

This curve gave a full range of tones.  The kid stands out. The background is busy but not obtrusive. The details on the screen of the tablet are still visible. I should also mention that with the new 4.2.1 build there is much  more difference between curve type than with earlier versions. Using the same curve settings, the 'b&w film like' selection had much lighter darks that the 'b&w saturation and value' selection .

As for using an 'after' curve, my take is that all the real action is in the 'before' adjustments both inside and outside the b&w tool. If you want to do something like color toning with the LAB tools, go at it. But once the tonality and conversion parameters are set any 'after' curves should work the same way similar curves work outside. the b&w tool. So I will leave that for another discussion

The final image. Enjoy the kid's hands and frown. My balloon caption is "STOP, SNEAKY PAPARAZZI !!! MOMMY is taking MY PICTURE!!"

And for the record here is the totally non white balanced color image that produced the final b&w.

Tuesday, September 9, 2014

This Stage Shot is a RawTherapee Challange

At first look there is not much to see. I found the low res jpg while poking around in a Lorde fan site. Lorde is, if you are not up on your pop music, a New Zealand teenage who at 16 played her first show in a 140 seat Auckland pub half filled with relatives and school friends. Last month at 17 she up her audience to an estimated 70,000 to 80,000 at Lollapalooza  in Chicago. And on September 26 she will be playing to a maybe sellout crowd of 5000 in Milwaukee. I will be sitting a few rows back from the stage with Charlotte and her BFF, Jessica. It's Charlotte's going-into-the-7th-grade-with-an-A-report-card birthday gift.

Naturally I will be there with a camera. Unfortunately it won't be my D7000. Only pocket cameras allowed. So I'm resurrecting my Canon S3IS, a 6mp oldie that hasn't seen a photo electron in years. It takes a moderately decent movie and can be updated with CHDK to output RAW files, Then I can handle some over exposure.

Unfortunately I expect a lot of overexposure. Lorde's new tour features a wild light show. A photographer's nightmare, the light show demands much under exposure (see above) or it will wash out a good hunk of everything on the stage. So I'll be depending on RT to drag details out of thick mud.

The fan site didn't lie. This is Lorde singing her double grammy winning super hit Royals. Auto exposure added 2.36 stops of exposure,

It's an obvious candidate for tone mapping.

 CIECAM  adjusted colors. contrast. and brightness.

Noise reductions did its thing. Since I started  with a 464 x 750 pixel jpg there wasn't much detail to worry about. Another adjustment is needed to move the histogram to the left and darken the blacks.

A Kodachrome 64 film simulation both darkened the blacks and enhanced the red. I now had the dramatic look I was hoping to see

Finally I resized the photo.  Because of the low res jpg don't look for fine details, but except for that problem this image is now a reasonable addition to a Lorde fan's twitter page . And I have a better idea of the photographic conditions I'll face at the concert.

After a few hours relearning how to use both the camera and CHDK I discovered the camera is less noisy than I feared. At ISO800 and exposures similar to the original jpg, RT gives me midtone  to highlight S/N of 20 to 40.  Not bad if it holds up at the concert. Plus if I go the CHDK raw route the camera has a stop of headroom for highlight reconstruction. So watch this spot after Sept26. I'll be posting a few examples on how things worked out.

Saturday, May 17, 2014

Matching skin tones for a Kodak Moment

Every now and then I've seen posts asking how to duplicate the look of a favorite film. I've played around with the idea myself with some occasional success.  Perhaps my most successful attempt was back in ancient years--my Photoshop days--where I exhibited an image that duplicated the National Geographic look of the 1920s and 1930s.  A bit of a hassle as I remember where it took several tries before what came off the print shop's Fuji Frontier machine look like what was printed in the magazine. A learning experience and my first attempt at color management.

Now we have RT with CIECAM . The tutorial is about duplicating what the 1950s ads in National Geographic called a Kodak Moment.

Why am I working on a jpg, Raw's poor and looked down upon cousin?  Because there are a lot of  jpgs out in the world, including a several year collection backed up on my computer. Call this a gentle reminder that RT is also one of the finest jpg editor around.

This image is from Charlotte's kindergarten dance recital. It was taken flashless and handheld with a point and shoot back when ISO400 was the ultimate in digital sensitivity. So it is nowhere near as crisp and noise free as an image I would take today. But it has family significance.

When Charlotte moved on to first grade she dropped out of dance because it was no longer just fun and play and had became real work learning real dance moves. But now that she is an almost seventh grader going on high school junior she has changed her mind. Her summer vacation will be afternoons of private dance lessons followed by several weeks of 8 to 5 dance camp. With weekly  recitals that I will immortalize in pixels and  then combine with the highlight of this recital to make a photobook or calendar for mom and the grandmas. Early Xmas shopping on steroids

Pass one was standard ISO high corrections to.brightened and cleaned up the image.

Pass two added an CIECAM tone curve to lighten the girls faces without washing out their costumes. Of the two curve choices the Lightness curve was stronger than the Brightness curve

Pass three was to use the  'All' algorithm to fine tune the facial tones of the image to match those on the cover of the Kodak pamphlet.  This wasn't done with any great science; just moving sliders around until the tone match looked reasonably close. Nor was this a challenging image since I was only working with one critical tone. But it does demonstrate a workflow.

 Converted with RawTherapee  which  can be found at

Thursday, May 15, 2014

Mini Workflow Spot Color

The original image of a couple kids being photographed by their mother.

All colors except for blue are desaturated using the saturation curve of the HSV tool.

Fine tune in CIECAM using the JS Lightness and Saturation algorithm.

That's it folks.

But, of course, with RT editing nothing is ever finished. So here is the new stuff you can create when you switch to the all algorithm and start draggin' them sliders around.  The hidden artist titles this 'Cindy's Nightmare - Do you have to tell wicked step moma you caught me sneaking out to the Prince's Rave?'

Main points
The hue slider gives a full range of of colors
When  ISO6400 noise is all the same color it becomes artistic texture. Fine tune that with the Noise Reduction Chromatic sliders
The other CIECAM sliders work pretty much as expected but with different intensities. For example the Q brightness slider is stronger than the L lightness slider and at 100% washes everything except the colors to white

Happy exploring your own Hidden Artist

Processed with RawTherapee  which can be found at