Saturday, December 29, 2007

What a difference a day makes

Two days ago, I was with my wife and kid at a lake where we hiked a little and I took some photographs. It was in the middle of a snowstorm and I needed extreme white balance values to get correct color. So yesterday, as I saw that the sky was clear and the sunset would give nice color I went there again to make photos at more or less the same time. The differences are astounding. Where two days ago this very distinctive tree looked like this:

Yesterday it looked like this:

Quite different indeed.

Another example (bigger version in the link):

Whereas yesterday:

This just illustrates how important it is to be somewhere on the right time to catch the light and the feeling of a place. You can see more images from this place in the flickr set here.

Friday, December 28, 2007

Extreme white balance

I encountered a situation yesterday evening where I was photographing in a snowstorm at dusk. I did not realize this at the time, but the light was so filtered that the camera registered basically purely blue, while our eyes saw everything as just grey even with some orange tinting. This is what the camera thought a scene should look like:

Completely blue indeed. It thought the white balance was basically similar to daylight. If you do "auto white balance" in Lightroom, this is what it looks like:

Lightroom chose 2850K, which is completely wrong. You would think that with all these clouds perhaps shade is correct:

Much better indeed but still way too blue. To get neutral color, I had to dial the white balance to 11:

Basically at the limit of what Lightroom allows, and this is the result.

Very close to what it looked like. It turns out that you can encounter natural conditions where you have to max out Lightroom's slider to get correct color. I even had some photos shot there that maxed out the slider!

For some more photos of this place, see my flickr set on this place.

Friday, December 21, 2007

Softproofing for sRGB?

Lightroom unfortunately does not support softproofing and it would be very useful for certain applications such as seeing how your image will turn out in print. Softproofing works for that case because a printer's gamut is usually much smaller than the monitor profile (usually close to sRGB) in places. In others, it is wider and there soft proofing is not very useful. Here for example is the sRGB gamut of a typical monitor (wireframe) compared to the gamut of typical US offset print (SWOP):

You can see that there is a large amount of color missing in the blue, green and red parts of the spectrum as you would expect because CMYK is a subtractive color model instead of additive such as RGB. On the other hand, the SWOP spectrum has much more definition in cyans and yellows. This is the origin of the widespread use of adobeRGB as a working space for offset as it will encompass most of the cyan lobe. If you softproof an image in photoshop for the CMYK process, you'll see many of the colors shift tremendously and you can correct for this.

On the web, I see many calls for softproofing in Lightroom so that you can predict how an image will look on the web. These calls are misguided however, and arise from these people having badly calibrated monitors and looking at the images in non-color managed apps such as Internet Explorer, or Firefox before 3.0 beta. In reality, soft proofing apps for sRGB is useless, since if you do it right, you will NOT see a difference at all. This owes to the fact that most monitors are approximately sRGB in gamut. Here for example is the gamut of a typical Apple LCD display compared with sRGB(wireframe):

You see that the display's gamut is smaller than sRGB everywhere. Almost every LCD screen (except the new wide gamut LCDs that very few people have - they are not cheap) is like this. Don't believe me? Here is an image with lots of colors outside the sRGB gamut softproofed for sRGB on my MacBook Pro:

Now look at the same non-softproofed:

Exactly the same indeed! Another reason that I think people get this wrong is that they do not set up the softproofing correctly. This is how you have to set it up for correct results:

You should NOT check the preserve RGB numbers button as you will not see the result of conversion to sRGB, but of when you would simply assume the image was in sRGB instead of the source profile (prophotoRGB in this case). My guess is that lots of people do this erroneously and think that their image changes a lot when going to sRGB. Concerning Lightroom, this means that if your image looks good on screen in Lightroom, it WILL look good when exported to sRGB. Of course, you cannot do much about your audience not calibrating their screen and not using color managed browsers, but using sRGB gives you the largest probability the colors will be correct.

P.S. Note that I used the color LCD profile supplied by Apple for the comparison above. If you hardware calibrate a Mac Book Pro display (even the LED ones) you'll see that the actual gamut is even smaller, making it even more impossible that you could see the effect of sRGB soft proofing on such a machine. ONLY when your display's gamut is larger than sRGB will you be able to see the effect of soft-proofing for sRGB.

Wednesday, December 19, 2007

mogrify LR plugin

See updates below: Mogrify in the default macports installation does not convert to the profile, but will only simply assign a new profile, which indeed is useless. To fix this make sure you install Imagemagick using the command
sudo port install imagemagick +lcms

Not long after I detailed a workflow to print at labs that gives far better results than sending sRGB images, Timothy Armes brings out a plugin for Lightroom that allows you to call mogrify, a part of the open source set of utilities ImageMagick. Check it out here. Highly recommended! This tool allows you to scale (choosing the precise scaling algorithm!) sharpen and convert to an arbitrary profile, all in one step, directly from Lightroom! You just need to know the commandline parameters directly although Tim is adding new stuff to the plugin all the time. For example, to mimic my workflow from a few days ago, you set it up to go to a 16-bit tiff in the ppRGB space, convert to a profile, you do not let Lightroom scale, but you set the mogrify plugin to do it. You just need to calculate the dimensions in pixels, which is easy (ppi*length(inches). In this example, I used fit inside and set it to 5400 pixels, which corresponds to 18 inches at 300 ppi.

As extra commandline parameters, I used:
-profile /Users/{yournamehere}/Library/ColorSync/Profiles/Costco-CO-Arvada-Lus.icc -unsharp 1.2x1+1.5+0.05

The first converts to the profile of my local costcos and the second applies an unsharp mask that nicely sharpens the output image. I need to play with the parameters a little to get the best results, but these are pretty good already.

At the end, the whole image gets saved as a jpeg. Very convenient!

Update I: Of course a minute after I post this, the plugin gets updated to support sharpening from the interface. So you only need the profile command.

Update II: To strip the profile from the files (to save upload time to your lab) use the commandline tool mogrify from after the export. The command is "mogrify +profile filename". If you have a folder of files, just cd into it and use * for the filenames.

Update III: It appears that mogrify does not actually convert to the new profile! So this might be far less useful than I thought. Stay tuned....

Update IV. It turns out that the ImageMagick in MacPorts by default is compiled without lcms support! So it will not convert between profiles, but just append another profile - useless. To make this work, you need to compile ImageMagick from source and installl it and then use the mogrify binary from that installation. This is fairly simple to do but takes some explanation. Bottomline: this can be made to work, but not without a small amount of effort.

For some reason, installing imagemagick in MacPorts with the lcms variant does not work! So you'll have to compile from source. Bummer!

UPDATE V: OK it turns out there is some weird issue because I have been running macports for ages. It did not actually uninstall and install ImageMagick when I told it to. To fix this, if you run into this problem, simply use the commandline:
sudo port -f install imagemagick +lcms

This will force it to actually install it, even though it finds remnants of old imagemagicks. After this the profile conversion works for me in the Macports install.

UPDATE VI: To strip the resulting image of its profile so that you have to upload less bytes, specify -strip in the commandline after the -profile statement. You can also just strip the profile by specifying +profile icc instead.

UPDATE VII: If you get strange results try specifying the source profile before the destination as in -profile /path/to/source -profile /path/to/destination. On my machine, the prophotoRGB profile can be found in an adobe installed folder and can be called like: -profile '/Library/Application Support/Adobe/Color/Profiles/Recommended/ProPhoto.icm' The quotes are essential because of the space in the folder name.

Sunday, December 16, 2007

A (mildly) Lightroom workflow for printing at costcos and getting superb color

Update: see edit at the end:

Update II (5/20/08): Lightroom 2.0 has made this workflow unnecessary. Check out my post on it.

I decided to detail my printing workflow I follow in Lightroom and Photoshop. This workflow will yield photographs up to 12"x18" (the largest most places print in 1-hour service - not a real limitation) with color and dynamic range rivaling and in some cases exceeding very expensive inkjets, but at a fraction of the cost. I use costcos for this purpose as they are fast, good, provide icc profiles and close to where I live, but I am sure other comparable labs will do fine too with a similar workflow. Labs that use Noritsus or Fuji Frontiers will all have very similar quality. My local costcos uses Fuji Crystal Archive paper, which is somewhat thin for larger prints, but gives excellent color fidelity and deep dynamic range. The machines raster scan a laser at three colors over this paper to expose the paper which is then developed using conventional chemical processes. You're actually getting a real photograph from a digital file. The workflow I'll discuss is done in photoshop, but you could use any program that can convert images between icc profiles. For example from Apple. This sort of sequence is necessary because Lightroom will not export directly to arbitrary icc profiles. Hopefully that will be built in in a future version?1

1. The first step is to download and install the icc profiles for your lab. Costcos makes them available on their photo upload pages, but they are actually done by dry creek. You can see if you can find your lab there. Download them and install them in a place where photoshop and other color managed apps can find them. On Macs that is simply ~/Library/ColorSync/Profiles or/Library/ColorSync/Profiles. On windows it is somewhere deep in the crypts of the OS. Check this page for instructions. Once installed, you should once every few months check if there is an updated profile.
2. Set up photoshop correctly. Many photoshop installations are setup incorrectly due to bad information floating around on the web. The way You should set it up is to respect embedded profiles and warn for profile mismatches. You get to the dialog in Edit:Color Settings. See below for a suggested setting:

Here I've disclosed the extra options, but they are usually correct. I'm just showing them for reference. The setting for the RGB working space is not that important. Setting it to ppRGB just makes photoshop throw up fewer warnings. When you get a color space mismatch warning when loading a file, always choose "preserve embedded profile." NEVER EVER choose "discard"

So only the top two options are meaningful. Now you have setup Photoshop correctly and it is time to describe the actual workflow:

1. Select the photos you want to print and crop them to the desired aspect ratios of your final prints. Typical print sizes are 4x6, 5x7, 8x10, 8x12, 12x18, etc, so your usual ratios are 2x3, 5x7 and 4x5.

2. Export your photos from Lightroom using the prophotoRGB profile (why ppRGB? check here) in a 16-bits Tiff or psd. At this point I use two different workflows depending on mood. I either scale in the output dialog of Lightroom, or in Photoshop. You should scale to your desired size at a resolution of 300 ppi approximately as this is the approximate resolution of the photomachines.

It s a good idea to create a preset for this.

3. Open one of the exported files in Photoshop.

4. If you did not yet scale to the final size, do it now using the Image->Image size dialog. Again, use 300 ppi for the resolution and type the size in inches or cm of your final print, making sure you have "resample images" checked. This will calculate the actual needed image dimensions in pixels for you and scale to that size. At this stage I use bicubic sampling for the resizing, but you could use whatever algorithm you prefer or perhaps a plugin such as Genuine Fractals.

5. Sharpen for final output. The machines have a resolution of 300 ppi approximately, but they are soft at that resolution which you should try to counteract to get the best prints. You can use many third party sharpeners for this purpose, but to keep this tutorial simple, I'll show you how to use the unsharp mask in Photoshop. Before I open this dialog, I usually zoom the image to 50%. The filter can be found in Filter->Sharpen. Zooming to 50% is a very old trick that allows you to judge the effect of the sharpening fairly well on screen. The settings below are fairly typical for me. An amount of about 150%, a radius between 0.5 and 1 and a threshold of 5 (to avoid sharpening noise).

This should look only slightly crunchy in the 50% preview in the big window. Experiment with this to see what works best.

6. Now comes the important step.2 In the Edit menu, choose "convert to profile." In the dialog, choose the profile for your printing service:

7. Convert to 8-bit color (Image->Mode->8 Bits/Channel.

8. Save as a reasonably high quality jpeg:

Make sure you do not select the embed color profile option. The machines ignore the profile anyway and the profiles are usually around 1.5 MB, so to save you upload time, do not embed it. Give it a name that describes which profile you used and to which size you scaled it so that you can identify it later.

9. Repeat steps 3 to 8 for all your photos

10. Upload to your lab and print!

You can easily create a Photoshop droplet for all this if you basically always go to the same size. Also check out my older articles detailing how to use the print panel in Lightroom to do basically the same thing, but including logos and such. Here is the original article and here I explain how to add borders and such.

1 At this point I should note that you could do this all with just sRGB files. However, in my experience, the color reproduction is not as good as I like. Using custom profiles gets me exact color reproduction.
2 At this point you could first softproof to correct for any out-of-gamut colors. I'll leave that for a later article.

UPDATE: Timothy Armes brought out a plugin for Lightroom that does all this without the need for Photoshop.

Wednesday, December 12, 2007

photos, copyright and more

The "web" is abuzz today because of a rather lame youtube video that used some photos from photographers active on flickr without their permission. The photo was taken down apparently because photographer Lane Hartwell did not like the photo being used without permission. Read her reasoning here. For some weird reason wired calls the video (which they link to in the article) creative. I don't see it. It's just lame insiderish jokes set to photos they never asked to be able to use. Wired links to an outrageous post by someone called Robert Scoble which I am not going to link to. Fake Steve Jobs often makes fun of this self-acclaimed internet expert - deservedly so. What a bunch of uninformed nonsense. Using someone's work without asking and attribution in a situation that is very clearly not fair use (the video is clearly meant to promote the maker's website) is rather unethical. How hard is it to ask if the rights of the original do not specifically allow this sort of use? Scoble apparently does not mind. Maybe that says something? Myself I am OK with non-commercial use, as long as people ask me. Parody is fine too since it is protected by copright law, but this video was NOT a parody of the photographer's work.

Monday, December 3, 2007

Zion national Park

Last August we were in beautful Zion National Park in Utah where among other things, we hiked the Narrows. This is an awesome slot canyon at the end of Zion Canyon.

The adventurers
This is my wife and daughter at the fork in the river. My daughter just loved hiking along the river and especially the many rapids that she would sometimes go up to her neck into.

Tenacious tree
This is a tree that somehow seems to be able to hold on.

Hiker in The Narrows
My wife ahead of us.

We also hiked at other places and even met a friend that my daughter had made a few days before in Bryce Canyon and her parents, so we hiked with all. Here is a tree perched between rocks:
Tree in gap
I like this because of the backlighting on the leaves.

And lastly a sunset from the campground:
The line

More images on the flickr set.