Thursday, September 18, 2014

Color management in Safari is broken in Mavericks too.

I've written here about the color management problems with Lightroom on Mavericks before here and here. With the recent release of OS X 10.9.5, color management now appears to work right in Aperture and in iPhoto. However, it is still broken in Safari and preview. This is quite disturbing. Amazingly, both Chrome and Firefox do the color management right. It appears that Safari has built-in code to deal with sRGB tagged images because it treats them differently than any other embedded profile. It ignores the sRGB gamma curve and assumes it is the same as your display gamma profile! Below is a little test link for your pleasure to illustrate the problem. Rollover to switch between adobeRGB and sRGB tagged images. The sRGB image will have the darkest patches blocked completely in Safari. The adobeRGB image is correctly displayed. In Chrome on Mac OS X, since it is color managed, you will see only a very subtle difference due to the gammas being different in adobeRGB and sRGB and there therefore being subtle bit errors but both displays are essentially correct. The same is true for Firefox.


Mouse over to see the problem. Loading the alternate image might take a few seconds. You won't see it unless you are on Mavericks/Yosemite and are using Safari.

On a well behaved browser these two images should be close to identical. Safari in Mavericks (I tested 7.1) is no longer well behaved and completely destroys the shadows. It is important to note that preview.app is also broken but in a different way. Strangely it does not display black correctly. Aperture and iPhoto do behave correctly as of 10.9.5 but used to be wrong in earlier versions of Mac OS X Mavericks. Photoshop, since it uses its own color management routines, behaves correctly too. Lightroom only behaves correctly in the Library views as I have shown before. In Develop it has the same blocked shadow problem as you see in Safari. This problem is non-existent in 10.8.

Edit: Before any confusion arises, I need to explain the numbers in the images above. The sRGB version of the image shows the values of r,g,and b in the sRGB color space as encoded in the file. The adobeRGB version is the same file, but converted to adobeRGB color space in Photoshop. The numbers are still the r,g,b values of the patches in sRGB space, but the file is simply encoded in adobeRGB. The display should therefore be identical in correctly color managed environments as it is in Photoshop.

Saturday, September 6, 2014

A purple desert

I came across this scene driving back from the Vermillion Cliffs last spring. I had stopped at Bryce and Calf Creek Falls along the way and now was heading back home with vague plans to stop at Goblin Valley. on the way between Capital Reef (an extraordinary place I can also highly recommend) and Hanksville I got struck by the scene below of just seas of purple/pink flowers on the desert floor in front of the impressive buttes. I had to stop and take some pictures as you can well imagine. I think it is extraordinary how life seems to find a way in these places.

Flowering desert
Seas of Purple. Buy a print. On flickr. On facebook. On Google+.
Nikon D600, Tokina 16-28 mm f/2.8 at 16mm, f/22, 1/40s, ISO 100.

Sunday, August 10, 2014

Further quantification of the Mavericks color management problem

I spent some time further quantifying the display problem that Mavericks introduced and that affects Lightroom, Aperture, and every other application that uses Apple color management libraries. In short, the problem is that shadows get crushed upon display. This is a serious bug that is remaining unfixed since OS X 10.9 and is apparently present even in the Yosemite beta. I am trying to raise awareness of this bug since I am getting no reply from Apple not from a bug report and not from directly emailing folks there. This should get fixed as it makes it tough to do serious work on Mavericks. You can work around it by using Photoshop which uses its own color management library or by using the soft proof feature in Lightroom. Mac OS X 10.8 and below do not have this problem and correctly show the shadows. This is independent of what color calibration you use and even shows up when you use Apple's supplied profile for your display.

I generated a simple photoshop file that has swatches of grey ranging from 1 to 100 in 8-bit scale and then used the system color taste dropper that you can get to if you open textedit and click the text color box. Then use "Show colors" and you can then "taste" any color on your screen and get the display values. These values are what is actually sent to the monitor and so are very useful for this purpose. Below I plot the values seen in Photoshop (correct), those in Lightroom Library and Lightroom Develop. I am not showing Aperture as those are the same as Lightroom Develop and also very wrong. I am using a double log scale to really show you the problem areas in the darker regions below r,g,b=25.

I did this using the nice plotly plotting service. The images sometimes take a short time to show up. You can find the data in the link on the bottom of the plot. Photoshop's light bump in the shadows is correct as sRGB has a little knee in the shadows. Lightroom Develop due to the Mavericks bug displays way lower intensity than it should leading to the crushed shadows that people are observing.

I also created the same swatch file in the color space of my monitor profile. The display of those swatches should happen at exactly the same display value as the input file. This really illustrates the problem I think.

Photoshop clearly does this correctly. The relation is almost exactly linear and any deviations are a single bit difference which is just a rounding error. Lightroom Develop shows way below. Lightroom Library is close but with a larger error than Photoshop. Below is the same data bit plotted as display error.

Mavericks causes Lightroom Library to be off by a full 8 points in the shadows! I hope this data is useful to somebody and helps some folks that have puzzled over dark shadows in Mavericks applications.

Saturday, August 2, 2014

Old Man and the mountain

Old man of the mountain flowers blooming at the shores of Andrews Tarn below Andrews Glacier in Rocky Mountain National Park. I visited this place after my visit to Sky Pond and Lake of Glass for sunrise. The mosquitoes were amazingly thick this morning and they were not impressed by the bug spray I was using ;-).


Old Man. Bigger. Flickr. Facebook. G+
Nikon D600, Tokina 16-28mm f/2.8 at 16mm, f/22, 1/60s, ISO 100, handheld.

Sunday, July 27, 2014

Cathedral Spires sunrise

Sunrise aplenglow on the majestic Cathedral Spires seen from the shore of Sky Pond.
Nikon D600, Tokina 16-28mm f/2.8 at 16mm, f/16, 1/5s, ISO 100

Cathedral Spires Glow. Sunrise casts alpenglow on the majestic spires over Sky Pond, a high alpine lake in Rocky Mountain National Park's Loch Vale.

Sunday, June 22, 2014

The many faces of Alstrom Point

My trip to the Southwest last April with a group of friends had three planned destinations. The Bisti Badlands/De-Na-Zin Wilderness, Alstrom Point and the White Pocket. I have pretty much gone through the Bisti Badlands images and posted those on my website except for a few that I am still working on. The Alstrom Point images are halfway done. For the White Pocket, I have a lot of work to do. I only posted two black and whites and the real stunners are still to come. This post is mostly about the Alstrom Point images. Alstrom Point is reached after a long drive over a dirt road and some four wheeling over a little slick rock. The location is a stunner though. You look out over Lake Powell and Gunsight Butte. We spent a single night there but even then it was amazing to see the different phases the view went through. I shot many different perspectives but the classical view is still what stood out. As always, click for bigger and for prints.

First sunset

Sunsight on gunsight butte.
Nikon D600. Nikon 24-85mm at 24mm, f/16, 1/25s, ISO 100. Grad ND filter.

The moon was out most of the night and very brightly illuminated the lake and rocks. The bright "star" in the middle is the planet Mars.
Moonlight illuminates Gunsight Butte and Lake Powell
Moonlight illuminates Gunsight Butte and Lake Powell
Nikon D600, Tokina 16-28mm f/2.8 at 16mm, f/2.8, 15s, ISO 1600.

The moonlight was so bright that it was easy to photograph the surroundings. I put my headlamp in my tent to obtain this:
moonlight lights the desert near Alstrom point. A headlight illuminates the inside of my tent.
moonlight lights the desert near Alstrom point.
Nikon D600, Tokina 16-28mm f/2.8 at 16mm, f/2.8, 15s, ISO 1600.

Close to sunrise, the milky way had come out very brightly and we had a lot of fun shooting images of it. I created two views - one vertical and one horizontal, by combining two exposures. One for the stars and one much longer for the foreground. You can already see the sunrise light starting to pour over. The bright star is the planet Venus in this case.
Milky Way and planet Venus rising over Gunsight Butte and Lake Powell as seen from Alstrom Point in the Grand Staircase, Escalante Wilderness. Vertical version.
Milky Way and planet Venus rising over Gunsight Butte and Lake Powell
Nikon D600. Tokina 16-28mm f/2.8 at 16mm, f/2.8, ISO 1600, Two exposures at 15s and 246s.

I also created a horizontal version:
Milky Way and planet Venus rising over Gunsight Butte and Lake Powell as seen from Alstrom Point in the Grand Staircase, Escalante Wilderness.
Milky Way and planet Venus rising over Gunsight Butte and Lake Powell horizontal.
Nikon D600. Tokina 16-28mm f/2.8 at 16mm, f/2.8, ISO 1600, Two exposures at 15s and 221s.

Close to sunrise, the glow started to drown out the stars but the pinks were coming out in force.

Swoop.
Nikon D600, Tokina 16-28mm f/2.8 at 16mm, f/11, 1/6s, ISO 100.

I also created some panoramics of which this is my favorite. It really should be seen much bigger in the link.

The grey before dawn.
stitched from 4 images from Nikon D600, Nikon 24-85mm at 24mm, f/11, 1/6s, ISO 100

Closer to sunrise, the glow turned red and orange:

Almost.
Nikon D600, Tokina 16-28mm f/2.8 at 20mm, f/11, 1/20s, ISO 100.

And finally the sun peeked over and gave a nice sunstar: The sun peers over gunsight butte seen from Alstrom Point.
The moment.
Nikon D600, Tokina 16-28mm f/2.8 at 19mm, f/22, 1/20s, ISO 100.

Again, enjoy these images bigger in the links behind the images.