Archive for the ‘Color’ Category

HDR – How it Works & How to Use it Properly

April 16, 2014

Summary – The clearest explanation of how HDR works I’ve seen. Also uses that explanation to demonstrate why many HDR images look so, well HDR-ish (as opposed to natural).

Another great post

by Ming Thein – a good photographer who is

An even better writer

To be expected if you attended Oxford at 16 ;)


I won’t dwell on my feelings about HDR (not all positive)

Ming pretty much says it all

(BUT – if you really want more – here are my 60 HDR posts)

.

Read his excellent article by clicking on this image

(and learn about dynamic range & zone system at the same time

2014-04-14_9-18-19© Ming Thein

 

 


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Color from the Camera – Does It Reflect Reality?

July 29, 2013

Part of a series – Color Managed Workflow

Today – White Balance & Color

.

A re-post of a 3-year old blog post of mine

Relevant to the ongoing Color Management series

It explains the effect of camera white balance

and how to deal with WB related color issues

Excuse the length – written in the style of the “old Ed”

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I ended the previous section, Part 1, with this -

Who painted my white bath orange???

These are two images taken straight from my camera without any post-processing. So? What went on here? The left image was made with a custom preset white balance setting (discussed below) and the right had white balance set to the daylight setting. If you read the primer and its link on color temperature you’d know that daylight temperature is in the blue range. The camera wants to make this blue more neutral and to do that needs to add red. However the actual light temperature was incandescent and adding red to that just made matters worse – thus the orange color cast (more than you need to know, but if you’re curious).

Click an image to enlarge it and note three items on the toilet -

  1. A calibrated color reference card on the front of the seat (pure neutral gray plus an area with black and white)
  2. A paper coffee filter next to the reference card. I’m going to save you lots of money with this – while getting you perfect image color; well worth the price of this course ;-)
  3. White tissue on the top of the tank

The color reference card has two potential uses -

  1. It can be used to create a custom white balance preset (read your camera manual) for use while capturing the image, and/or
  2. It also can be used in post processing to tell your editing program what part of the image is truly neutral

The coffee filter can be used to create a custom white balance preset (as you would with a reference card but for $10-$50 cheaper)

  • And – about $100 cheaper than the most acclaimed device for setting custom WB presets, the Expodisc
  • Disclosure – I’ve never used and Expodisc but will say
    • that the coffee filter’s results, as measured by how neutral are the neutrals?, is spot on the mark
    • Expodisc benefit claims to the contrary are
      • neither observable by my eyes (R=G=B is neutral, i.e. no color cast, regardless of how it is achieved)
      • nor worth $100 to me as I get the same result with the coffee filter
    • there are those who mock the coffee filter approach but
      • Do your own experiments and decide for yourself
      • Don’t depend on the claims of others – including me
      • Shoot several ways and then examine the RGB components of various neutrals in your image
        • You will need an image editing program that will report the RGB component values to you for any point on an image under the mouse cursor; fairly common function available in most programs
        • If the RGB values are equal to one another – for a point in the scene that is neutral – there is no color cast & your WB setting is correct
        • Neutral is neutral, regardless of whether it came from an Expodisc or a coffee filter
        • If you don’t understand “neutral” reread the final section of the Color Primer

NOTE – a color reference card serves two separate purposes as stated above. The coffee filter or Expodisc only serves the purpose of creating a custom preset. That being said, the reference card is both less expensive and more useful (but buy a good card; it’s worse than useless if it’s not a pure neutral).

The tissues are in the scene to give your eyes a point of reference for white.

So much for the preliminaries but, before reading further, put your camera on your tripod, take it to an indoor room (no natural light), and follow along. You won’t learn to do the steps just in your mind. You need to actually do these things. There’s no time like now.

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Here is the bath again. Three images from the camera with no post processing. White balance (WB) settings from left to right

Auto, Incandescent, Daylight

On the face of it, depending on your color-IQ (click for a fun test), the color of the first two appear to be “OK”. Obviously, the third is way off. Moving beyond “the face of it”, let’s look at actual RGB measurements and see what they tell us. All R/G/B readings were taken by zooming in on the reference card and reading the small white area with my image editing program -

  • Auto                  177/167/128
  • Incandescent    188/173/132
  • Daylight             222/164/64

Several observations

  • None are truly neutral; the two best have a “warm” cast (which some viewers may find pleasing)
  • The G values are similar and are not a principle reason for color differences among the three
  • The greater the difference between the R & B value the greater the red/orange cast; this is shown in the 3rd image with its severe orange color cast
  • Auto did a respectable job in comparison to tungsten – as should be expected
  • The fact that this measured white sample on the card is not brighter (RGB components nearer to mid-250′s) has to do with exposure and not with color balance. This was shot
    • Matrix meter, 0 EV, and
    • The meter’s design goal of making the average of the scene middle gray explains the more or less average brightness of the white

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Next let’s compare the correct fixed camera setting, incandescent, against two custom measured presets. From left to right -

Incandescent, Custom made with calibrated color reference card, Custom made with coffee filter

The difference between incandescent and the two customs is obvious. The customs are whiter – no orange cast. The difference between the customs is less obvious – because they’re the same for all practical purposes. Here are the R/G/B readings -

  • Incandescent    188/173/132
  • Card                  175/174/169
  • Coffee               175/178/179

Observations -

  • Not much to choose from between the two custom measured WB results
  • Although incandescent looked “OK” in the first “shoot-out” – due to a lack of anything better to compare it against – its orange color cast is obvious in this comparison
  • If accurate color is critical, extra measures beyond just trusting the camera’s WB are needed – especially with indoor lighting
  • You can see the problems even in this benign indoor lighting situation; add mixed lighting and you’ll have real problems

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If we shot in RAW and included a reference card (or equivalent) in one image, we could use that image to fix any color problem caused by user WB errors – in all images, not just the reference image. Here’s the image made with the incorrect daylight setting and how it looks after correction during the RAW to JPEG conversion.

The R/G/B measurements for the corrected image are  176/179/180 which are as good as achieved with the custom WB settings in the previous example. This is no surprise; that’s how it’s supposed to work if done right. How this is done in post processing differs from program to program. The basic steps are -

  • Go to an area named something like color balance or color correction
  • Look for an option that allows you to set (define) a gray (neutral) point
    • Keep in mind that even if it says “gray” all that matters is  that the reference is neutral (R=G=B) which includes white, black and all 254 intermediate gray tones
  • Click on your color reference card (your neutral or gray point) in the image – and you’re done.
  • It’s that simple.

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How about if you didn’t shoot in RAW? You’ve got lots of work – possibly followed by lots of disappointment. Google to find color correction suggestions – both good and bad – and then don’t make the same mistake again. Here are three images that show my luck (or lack thereof) in trying to fix a JPEG version of the daylight WB setting. All were done in Photoshop Elements. Each used a different PSE color correction option. The colors are poor although the right hand image, which took advantage of the reference card, is getting there.

With time, effort, a different assortment of programs, prayer, and so on – probably one could do better. BUT WHY??? It’s all so unnecessary. It took me several times as long for each of these poor results as it did to fix the problem correctly in RAW.

  • L   218/178/116
  • M  236/175/87
  • R   133/131/121

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How do we do the coffee filter trick?

  • First read your camera manual for how to create a custom WB preset
  • Next, hold the coffee filter over your lens as shown below
  • Point the camera at the subject (we want it to see the light in the scene)
  • You’ll need to have focus set to manual
    • The camera can’t focus with the coffee filter on the lens
    • If it doesn’t focus it won’t shoot (under normal settings)
    • The camera doesn’t need to be in focus for the preset measurement to work
      • It just needs to see & measure the light temperature
      • To see & measure it needs to shoot – so once again, manual focus please
  • Press the shutter release & do whatever other steps your camera requires to save and use this preset
  • That’s it

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Please understand that with white balance there is no “one right way”. It’s not governed as strictly by the laws of physics as is exposure. Further, how white balance is implemented varies from one camera make to another – and even within different models of the same make. What I’ve explained is what works for me and for countless others including top pros. You will find others who may quibble over some specifics (especially the coffee filter or when to use – and more importantly, not to use – Auto-WB). As I said before, take personal responsibility for yourself & your photography. Experiment, practice  and, in doing so, draw your own conclusions about what is best for you. Above all – have fun!

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Nik Collection Troubleshooting Tips

July 23, 2013

Google’s Nik Collection, with its attractive price,

Has introduced lots of new users to Nik software

New users have a lot to learn

My tutorial series is a good place to start

However, occasionally troubles arise beyond normal usage

Troubles with getting the software to run – period

Or – to run correctly

.

Here are a few tips to solve problems

Getting Nik Collection programs to run properly

Based on years as a Nik beta tester

Encountered 5 users with problems in just the past week

So I decided to update my 2011 post on this topic

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1. When all else fails – or maybe even before trying anything else – the generic “fix-it” for many problems during beta for many, many testers was

Reinstall the Program

I suspect that once you move to the top of the Google Nik support queue this is going to be the first thing that they suggest

Try it now; save yourself time in the support queue later

1a. Install Order (recent note on test site)

“If you installed the Nik Collection first and then installed LR5, the plug-ins won’t show up

You’ll need to run the installer again”

This likely applies to any Nik Collection host program, not just LR

A specific case of the Reinstall the Program theme

2. Image Quality Issues – Nik programs were “early adopters” in using a video card’s graphic processing unit (GPU)

Not all cards work!

The problems usually show up in the form of image quality problems – odd colors, square patches with different tonality than the rest of the image, etc.

The solution is to open the program’s Settings menu and

Disable the GPU

You must restart the Nik program (& its host – PS, LR, Aperture) after doing this for it to take effect

You may want to try this even if everything seems fine just to see what speed impact using (or not) the GPU has

Much more GPU detail in item #5 below

3. Odd crashes and start-up difficulties – This next tip isn’t a cure-all but may solve your particular problem

The Nik Selective Tool is known to occasionally give problems (this is a little window that pops up over your host program – PS only)

The ST issues arise usually as a result of installing a new plug-in – key word here is install and not the plug-in itself

Maybe (hopefully) since the major (only) change by Google since their acquisition of Nik nearly a year ago was to the install & update routines, this problem has gone away

I don’t know because information to beta testers isn’t as free-flowing as before

4. Speed - Do not allocate more than 55-60% of available memory to Photoshop (go to Performance under Preferences in PS)

5. More on Graphics Processor Unit (GPU) induced problems posted at the Google test site 7/22/13

Even though this was an answer to a Color Efex Pro question, it applies to the entire collection

a.Video Card Drivers

Mac Users: Generally the video card that comes with your Mac will be updated automatically. The exception may be when there has been an additional video card added. In that case the user may need to go to the video card manufacturer’s website to download an updated driver for their secondary GPU. If you are using Mac OS Snow Leopard (10.6) ensure to update to 10.6.6 or higher as this can affect performance. If this does not apply to you, please go to the next section below.

Windows Users: Locate the manufacturer of the GPU as well as the model number. Once this is determined, it is then recommended to go directly to the GPU manufacturer’s website (best option) or if that is not possible to go to the computer manufacturer’s website (secondary option) to obtain an updated video card driver. It is NOT recommended to use Windows Update as in general we have found that these drivers are not updated as frequently. To identify which video card you have please do the following:

  1. Click on Start >Control Panel>System & Security >System >Device Manager and then click on the plus next to Display Adapter, this should display the make and model information.
  2. Go to the manufacturer’s website (you may need to search for it via Google) such as Nvidia.com and with the model number you should be able to search for the latest driver. If you are unable to locate the driver you may need to contact the manufacturer of your computer to obtain an updated driver.
  3. Once the latest GPU driver is located,download and install the new driver.
  4. Restart the computer and try your Nik program once again.

b. Disable partial GPU processing

If after following the above steps you are still experiencing the same issue, the next step will be to either disable the GPU (if possible) or force your Nik Program to not use the GPU (safe-mode). In order to disable the GPU in your Nik Program please do the following:

  1. If you are able to open your Nik program and can see part of the interface, see if you can click on the”Settings” button in the lower left.
  2. In Settings locate the section “GPU” and expand it, in this section you will see a check box “Enable GPU Processing”, uncheck this so the GPU will be disabled, then close the settings window.
  3. Close out of your Nik program (click Cancel), quit out of any and all host applications (Photoshop, Lightroom, Aperture), and then relaunch your Nik program to see if this corrects this issue.

c. Disable all GPU processing

If you are unable to disable the GPU via Settings OR if the issue is still unresolved (e.g. your Nik program crashes or the buttons are not displaying correctly), please try the following steps below after quitting out of all host applications (Photoshop, Lightroom, Aperture):Mac Users:

  1. Open a finder window (or double click on the Macintosh HD on the desktop) and navigate to:
    Macintosh HD : Users : <user name> : Library :Preferences : Google : Color Efex Pro 4 (or whichever program….)

    • OSX 10.7 or later: hold the Option key and go to Go > Library to access the User Library
  2. Locate the file, ColorEfexPro4.cfg and right-click and choose “open with…” and then click “Choose” and then locate the applications, “Text Edit” to open this file.
  3. At the very beginning (before all the text) of the configuration file, paste the following code below verbatim:

    <configuration>
    <group name=”INTERN”>
    <key name=”UseSafeMode” type=”bool” value=”1″/>
    </group>
    </configuration>
  4. Now save the file, close it and relaunch your Nik Program and see if the issue has been resolved.

If the issue persists please reply with the Color Efex Pro 4 (or whichever) folder underUSERACCOUNT/Library/Preferences referenced above. This contains log and settings files that will help us understand what else may be occurring.

Windows Users:

  1. Click Start and type in the search box below: %localappdata% (exactly as shown with % symbols on each end),when the yellow folder “Local” is displayed in the search list, click on it.

  2. The local folder will open, now double-click on “Google” followed by “Color Efex Pro 4″ (or whichever) and locate the file ColorEfexPro4.cfg (or whichever) and then double click to open. Windows will ask you which application to use to open this file, locate and choose “Notepad”to open.

  3. At the very beginning (before all the text) of the configuration file, paste the following code below verbatim:

    <configuration>
    <group name=”INTERN”>
    <key name=”UseSafeMode” type=”bool” value=”1″/>
    </group>
    </configuration>
  4. Now save the file, close it and relaunch your Nik program and see if the issue has been resolved.

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Everything is a Remix (Even Photo Creativity)

January 15, 2013

Everything is a Remix

Is the subject of a wonderful 10 minute TED talk

General Theme – everything is built on what went on before

This is a follow on to my post on Derivative Art

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The above TED talk is part 1 of what evolved to a four-part series.

The Complete series is here

Here is some general info on the “Remix Culture” - Wiki

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“If I have seen further it is by standing on the shoulders of giants.”

From the letters of Isaac Newton

This is a familiar form of the “shoulders” quote, but

It goes back to the 12th century

A Western metaphor with a contemporary interpretation meaning

“One who develops future intellectual pursuits by understanding and building on the research and works created by notable thinkers of the past”.

It’s a good thing F=ma wasn’t patentable ;-)

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The goal of US patent law is

“promote the progress of useful arts” (emphasis mine)

BUT - in many ways it does anything but that

What if Apple filed a 20 page patent for

Unlocking a tablet device with a finger swipe?

or another for

Putting beveled edges on computer tablets?

or?? the list goes on….

Oh, I forgot. Apple did do that! :-(

In a similar vein -

What if Henry Ford had patented human transport via gasoline powered wheeled vehicles?

“I invented nothing new. I simply assembled the discoveries of other men behind whom were centuries of work … progress happens when all the factors that make for it are ready and then it is inevitable.” — Henry Ford

Or the Wright brothers – human transport via powered flying machines?

AND – speaking of wheels…. ;-)

Music -

“The words are the important thing. Don’t worry about tunes. Take a tune, sing high when they sing low, sing fast when they sing slow, and you’ve got a new tune.”  Woody Guthry

Art -

“Good artists copy, great artists steal.” — Attributed to Pablo Picasso

General -

“Originality is the art of concealing your sources.” — Attributed to various sources including Ben Franklin & Thomas Edison

“Substantially all ideas are second-hand, consciously and unconsciously drawn from a million outside sources   Mark Twain

On a personal note -

What if I had patented “Adaptive shortest path routing” (look it up in one of the Bell Lab Tech Journals circa 1973)?

It’s at the heart of all modern digital communications – internet, phone, ….

I’d be a very rich man. In the day AT&T offered me a senior Bell Labs position (I declined) and they totally revised their long distance phone system (the only one there was in the US then – pre-divestiture) based on their estimate of capital expenditure savings to the tune of billions per year from my invention

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Name Change that tune – (Steve Jobs quotes)

1st came -

“We have always been shameless about stealing great ideas.”

When asked in an interview the 80′s, at the Mac introduction, about using Xerox Palo Alto Research Labs user interface designs (including the mouse) for the Mac

Later came -

“They are shamelessly copying us.”

About Microsoft and the operating system which would be released as Vista

and more recently -

“I’m going to destroy Android, because it’s a stolen product. I’m willing to go thermonuclear war on this.”

On Android, a mobile OS that he felt was copied from Apple

It must depend on whose foot the shoe is on….

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10,000 Hours, OR – Practice, Practice, Practice….

January 14, 2013

Some Potpourri

.This post has several purposes -

1. Preach the sermon about practice yet one more time

2. Introduce a great online magazine (location of sermon)

3. Provide some amazing music (part of e-zine sermon)

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The meat of this post is contained in the five links below

If you’re one of the 50% or so who don’t follow links

You can stop right here :-(

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1. You may have heard of  the “10,000-Hour Rule”

Popularized in the book, The Outliers   1-12-2013 9-23-52 AM

The book is a very interesting read

Whether you agree with its premise or not

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2. Here’s an article on the 10,000 Hour Rule and Photography

It appears in “on landscape” 1-12-2013 9-25-23 AM

A United Kingdom based online magazine

This particular article is free

Includes lots of interesting reader comments

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3. Even if you’re not interested in practicing or landscapes

The article includes links for several

Musical performances of various genre

(To illustrate what a little practice – or a lot – can do)

I’ll include one here.

An amazing guitarist

Go to the article if you want more

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Personal note -

I believe there’s an element of truth in the 10,000 Rule

From 2002 to 2007 I amassed over 10,000 hours

of “photography time”

During that time I progressed from

1st time camera owner (2MP P&S) to

Advanced winner of everything in sight

From May 2004 until summer 2009

I shot every day

Averaging 75 shots a day

Just sayin’ – Putting in the time can’t hurt

Now at the start of that time, if someone had said -

Camera or guitar – which will it be?

After listening to Tommy Emmanuel – tough choice

Probably still the camera because I love nature

[Update - for readers from the land of Oz the guitarist, Tommy Emmanuel, is one of your own. Quite a treasure.]

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