Headhunters

"You have to appreciate that the deforestation of Nias started when they were no longer headhunting!  So it was functional."  Gerard Meijssen often expresses unusual perspectives that make me laugh, but he's seldom wrong.  This photograph was taken in Indonesia.  Here's Gerard's translation of the Tropenmuseum's caption:

Repronegative. The best known island of the range to the west of Sumatra is probably Nias. It was at any rate the biggest and most populous. In the time of the VOC, the island was best known as an exporter of slaves to Atjeh, Padang and Benkoelen. In this way the gentry of the hierarchical Nias earned the gold needed for dowries and the ritual feasts. Nias was a society of warriors who not only enslaved people, they also went head hunting, for instance for the burial ritual of a nobleman. The colonial government tried to end this (P. Boomgaard, 2001). A group of subdued headhunters, Nias “a group of head hunters came to submit themselves” Nias, Northern Sumatra, ca 1920

Go ahead and double check the museum's official metadata if you can read Dutch.  Gerard seems perfectly serious, which is a little hard to stomach if, like me, you envision reruns of Gilligan's Island when the word "headhunters" enters a conversation.

Headhunters really existed.  And after too many formative years of squandering brain cells on the best bad sitcom of all time I'm restoring an actual photograph of headhunters.  Here's a thumbnail version of the image the Tropenmuseum provided at high resolution. 

This was probably photographed in or near the village of Bawemataloeo.  If Gerard is right, these people took heads as trophies in battle.  An effective way to put fear into one's enemies!  Although (per Gilligan's Island) I'm slightly embarrassed to discuss this subject, it is fascinating to see the people who lived that way.  And a relief to know it's historic.  Then I remember the deforestation and my political correctness meter breaks.

This seems to have been digitized from a print on textured paper with directional lighting.  The scratches aren't clear lines: they look like little horizontal nicks stacked over each other.  It's quite difficult to work on.  I've been spending most of my time at 200% and 300% resolution with a healing brush selection three to six pixels wide.  The hardest part of it is repairing this man's face.

When an image has problems that are solvable yet difficult, the mellow approach is best: address the parts that are easy to fix and go work on a different area when it starts to seem frustrating.  Come back after the subconscious has pondered the situation, work on the tough area again, and slowly turn big problems into little problems.

One of the things I do is keep an unaltered version of the image handy and pause occasionally to view sections side by side.  That helps to distinguish photographic damage from real data.  It also sustains my morale through a hard restoration.  Here's how that section looks so far.

Pattern recognition

The human nervous system is wonderful at pattern recognition.  That's bad news when photographic damage forms a distinctive pattern because even when restoration removes nearly all of the damage our brilliant brains still see a pattern.  There's a trick to overcome that effect.

There are always more good images to restore than time to restore them.  A friend is collaborating on the Haitian restoration and the Indonesian restoration is nearly finished.  Today's post looks at a different part of the Indonesian portrait where the challenge looks difficult and is actually even harder than it seems.  Here's what we're dealing with:

Vertical streaks at close parallel are a tough kind of damage.  We want to erase those streaks without losing the folds of the garment or the shape of the earring.  I worked on this with a healing brush at six pixels diameter, which was just the right width to erase those lines.

Healing brushes work by sampling one area of an image and performing a complex mathematical operation to blend data from that region with a different area.  If you think of this intuitively, the way to heal a scratch that goes from a light section of fabric to a dark section of fabric is to choose a source region that has similar light and dark areas.  One by one those scratches start to disappear.

The progress feels rewarding for a while until you reach a point where the scratches are nearly gone.  But darnit, you still see 'em.

This is one situation where reviewing an area at 200% resolution is not sufficient: subtle patterns emerge when you pull back to 50% resolution.  Our brains recognize lines--especially lots of parallel lines.  We distinguish lines even when they're faint and discontinuous.  This gets very frustrating when you're trying to erase them.

Fortunately you don't have to sit at the computer for hours until you start climbing the wall.

The secret to finishing work on this area is to recognize that your brain is just reacting to a pattern.  All you really need to do at this point is break up that pattern and randomize it.  So instead of editing in an endless series of vertical strokes, increase the pixel selection and follow the curves of the garment.  Clone stamp the delicate areas such as the necklace. 

A neurological phenomenon called lateral inhibition might have something to do with why we see this.  If the phenomenon interests you, the Mach bands illusion and the Cornsweet illusion make good reading.

Making light of troubles

While Garrondo and I were discussing the Photoshop curves tool last night he asked me to blog this restoration as an example.  It depicts a pair of Balinese dancers and dates from 1929.  The photograph also has a lot of other distracting elements, so let's fast forward to the completed restoration and then concentrate on a few points.  Here's wishing the actual editing went so quickly; it actually took a day and a half.

The most difficult part of this restoration was not the obvious marks and streaks.  It was the tall flower on the right dancer's headdress.  The dust specks weren't so hard to remove; the problem was what to do with all that streaky low contrast bands which intersected it.  Compare it to another flower at far left: the unrestored versions appear so different that side by side, they hardly look like they both come from the same photograph.

Regardless of what caused the streaking (I've got several guesses), the first question was whether to correct for it.  So work began by getting rid of the spots specks, while leaving the streaks unaltered.  Sat back for a view of that version and decided the streaks really needed to go; they served no visible function other than distraction from the primary subjects.

The next phase of editing didn't try to create a totally even background.  I didn't want to alter much adjacent to the dancers themselves.  One of the few areas where background absolutely had to be patched near a costume element, though, was that darn flower.  Used the clone stamp at a low hardness setting to get a natural effect.  Afterward several brightness adjustment masks reduced the starkness of the differences between portions of the image.  Also enhanced contrast at the rose, which ultimately meant re-cloning the background in that area.

The final result on that flower might be a smidgeon too contrasty.  Yet considering what there was to work with, it was a pleasure to see it come this far.

Another aspect of this restoration was really gratifying at the end, although it's subtle enough that it's scarcely the first thing to catch anyone's eye.  In the original photograph the face on the dancer at right is slightly overexposed.

To see the difference a curves adjustment makes, here's a view of her as she looked after all the edits except for the curves adjustment had been completed.  There's a blandness and flatness about her; it's hard to catch her expression.

Now have a look at how the curves tool brings out the midtones.  Her face is still youthful but less like putty; more personality shows.  And the intricate contours of her headdress and shoulder band become more noticeable.

Restoration can be tedious work.  An image such as this one has so many obvious flaws that one runs the risk, out of exhaustion, of shortchanging the final adjustments.  I wish I knew the name of the somber young dancer in this photograph.  Those eyes look like she saw a lot of life at an early age.

What is a stain?

The Tropenmuseum has provided a very special challenge.  This post is probably the first glimpse of it to become visible to the public.  Roughly speaking, it's something like the Bayeux Tapestry of Indonesia.  The museum had it professionally photographed in twenty-nine parts.  Then they discovered that none of the digital segments quite matched together: the lighting was slightly uneven from left to right and the thin tapestry fabric had shifted so that the fibers and images no longer matched neatly.  These problems affected every one of the twenty-nine segments; the museum staff thought the image couldn't be stitched.  We've had very enthusiastic responses from the museum staff now that I've pieced it into a single file.  It's a huge job: 992.4 MB.  Now it gets interesting.

There's a lot more to be said about the digital restoration on an image that's nearly a gigabyte than one blog post can encapsulate.  One part that's easy to recognize is the large brown stain that runs vertically along this segment.  Today's post takes a different approach to repair than the last post because this time the original design remains visible within the damaged area.

In terms of digital image data, this stain consists of three elements:

• Brightness
• Color
• Contrast
  

If one thinks of a stain as too dark and deficient in blue and lacking contrast, then the way to eliminate the stain is to brighten, add blue, and restore contrast.  The concept is simple.  It's mainly a matter of creating enough masks to make the corrections in small increments.  Stains tend to be uneven so different portions require individual adjustments.  Here's an interim save as it looks on my monitor right now.

The proportions on this are reduced substantially from the original file, which was 13MB on this cropped area.  Yet it can be informative to see the work before the stain removal is complete.  No cloning has been done at all in this stain correction.

President of Suriname visits WMF partnered museum exhibit

Good news from The Netherlands.  President Ronald Venetiaan of Suriname has visited the Tropenmuseum exhibit about the cultural history of Suriname.  First Lady Lisbeth Venetiaan saw the exhibit last Saturday and was so impressed that she returned with her husband the next day.  The Suriname exhibit was developed in partnership with WMF Netherlands and the Open Progress Foundation.