Ever since I switched from Nikon software, ViewNX, to Adobe Lightroom, I’ve been meaning to check how portrait color handling matches up. In my most recent portrait session, I took one test shot with my subject and a color chart under the same lighting I used for the rest of the session. This allowed me to calibrate the white balance (WB) in post-processing by sampling one of the gray patches in the chart.

The first photo shows how the camera (Nikon D300), using the Portrait Picture Control would have rendered color using the Auto-WB setting. The second shot shows how sampling the gray patch in ViewNX 2.2.5 adjusts the WB. The change is subtle: just a slight warming up of the skin tones. The final shot is processed in Lightroom 3.6 using its Portrait camera profile. I notice a change in how shadows render — lighter in this case — but color, especially on those all-important skin tones for portraits is pretty much the same.

This is good news for me, because all along I’ve feared that though Lightroom’s more versatile and robust features offer many benefits to my post-processing, I was losing the fidelity that a Nikon software product would yield. I’ll let you be the judge, but at least for this example, where light was fairly well controlled, I don’t see much of a difference.

Trying to get color accuracy is often an exercise in squeezing the balloon: you get hold of one end, and the other gets away from you. I am more interested, however, in understanding how different cameras in my kit render color so I can know what I must do to color-match (as best I can) when I use two of them in the same shoot. To this end, I decided to see for myself about the claims that D7000 color rendition is off when compared to other cameras in the Nikon line-up. We should always expect some differences, but will they be large enough to matter?

The first set of photos were shot under different lighting conditions, using the same lens (85 f1.4D) and Picture Controls, using Auto White Balance.

1. D300, overcast window lighting	1. D7000, overcast window lighting
2. D300, mixed overcast window lighting and flash	2. D7000, mixed overcast window lighting and flash
3. D300, mixed overcast window lighting and flash	3. D7000, mixed overcast window lighting and flash

The results are fairly close. It looks like the Auto white balance (Auto-WB) algorithm is doing a fairly good job of accounting for whatever color-casts the imaging chain (including the Anti-alias filter, Bayer grid and sensor) may be introducing. Would we get closer if we set our own white balance setting? To see this, let’s take the 2nd and 3rd samples and apply the Flash WB setting.

4. D300, mixed overcast window and flash lighting	4. D7000, mixed overcast window and flash lighting
5. D300, flash lighting	5. D7000, flash lighting

Surprisingly (to me at least) these seem to show a greater difference between the D300 and D7000 than the Auto-WB samples. Perhaps, knows something we don’t. For the final set of samples, we use a reference in post-processing, either true white or gray, to generate our own white balance.

6. D300, mixed overcast window and flash lighting	6. D7000, mixed overcast window and flash lighting
7. D300, flash lighting	7. D7000, flash lighting

I still need to ponder these results a bit better, but to my eye, it seems like at least for these lighting conditions, I can trust Auto WB to get me pretty close to a match between my D300 and D7000. No doubt other lighting conditions (Incandescent, Fluorescent, and a mix thereof) might prove more difficult. I’ve also learned that my strategy to set a given temperature or default WB setting may not be best when I want to color match. As for the gray card results, at first glance they appear no better in terms of color matching than the Auto-WB results. Regarding which of these approaches yielded the most accurate color, I’d have to say, again, Auto-WB did surprisingly well, and the gray/white reference point method also yielded reasonably good results. I am more concerned with matching camera(s) output, though, than in producing accurate color, as I have learned first hand how getting “real” color is a slippery goal.

Lots to think about here, but the good news is that the colors aren’t wildly different, and that for most practical situations, color matching is fairly good.

Continuing where we left off, we now take a look at how to capture art pieces with accurate color. To illustrate the problem, here are two attempts to capture a particular piece, one using flash, and the other ambient light. The flash exposure was taken with the flash pointed up, to prevent reflection from the canvas, and the flash unit was “flagged” to prevent direct forward spill of light, again, to avoid reflection in the paint. The ambient light sample required a long exposure (1/6 of a second), so use of a tripod proved essential.

Using flash

Using ambient light

Both of these images exhibit a yellow, overly warm color cast. The issue arises from the white balance used to capture these images. Some cameras do a better job than others auto-detecting the correct white balance, but this often proves challenging when light sources, say daylight and overhead incandescent lighting, mix. While it is possible to adjust white balance on the spot, a method I prefer for this type of work involves a reference shot using a gray card (like this one), as shown here.

Using a gray card

The gray card becomes a reference that, when used in post-processing, yields white-balanced color. You’ll have to trust me, but these next two corrected images match the original much better than the captures we showed above.

Flash, color-corrected

Ambient, color-corrected

And now you can appreciate why the “final product” we showed yesterday looked so “right.”

With cropping and resizing

One often hears the advice to not worry too much about White Balance (WB) in the field. Shoot RAW, and you can always correct it later. This begs the question: correct it to what? If you have photographic memory and can remember exactly what the colors looked like when you pressed the shutter, then you will be able to tweak away until you get your photograph to look just right. On the other hand, if like me you can’t remember what color socks you are wearing right now, you may need to take care of WB on the spot, or you may need to decide that you will approach WB by feel, i.e., what looks best to you, in post-processing.

As we briefly saw in our previous blog entry, this presents you with a choice:

1. Do you want the colors to accurately reflect the scene as you photographed it, sometimes called achieving actuality, or
2. Do you want the colors to feel right, as in, for example, making sure that white is true white and not a color-cast version of white?

One the most challenging shooting scenarios I often encounter involves subjects lit under staged lighting. Here the two-way choice for WB proves difficult. On the one hand one can go for naturally looking skin tones, but if the stage lighting is producing a color cast, keying on known whites and grays in ViewNX (or alternatively setting WB per a white/gray card on the spot), will produce non-actual colors in the rest of the scene. The skin tones (and clothing) will look natural, but you’ve effectively altered the way the scene looked. Let’s examine this by example.

Here’s the original version, as shot, with a WB manual setting of 3450K. I arrived at that setting by using the Liveview mode in my Nikon D90 to view the scene as I adjusted the WB temperature until what I saw in the LCD screen matched the scene. Unfortunately, this is only good enough to get in the ball park. The camera’s LCD screen is not color calibrated and could lead me astray. Nonetheless, the unpleasant orange skin tones we see in the original capture are real, a byproduct of the stage lighting’s color cast.

Deciding to try for more natural skin tones would win over “actuality” for this shot, I first tried the Incandescent (3000K) setting. The orange skin is gone, but is now replaced by too much pink.

Fortunately, we have some candidate whites and grays in the scene. The white blouse on the right seems at first like a good candidate for setting WB with the eye-dropper, but unfortunately, it is too bright. The gray in the risers where the choir members are standing, however, does the trick.

This final try produces the most pleasant results for the skin tones, and a quick check of the white blouse reveals we have nearly achieved true white. However, the rest of the colors, in particular that blue background, no longer match the colors in the actual scene. To make a final decision on whether this is acceptable, we ask ourselves the “what is this photograph about” question. The most obvious answer is that the subject is the lead singer, and since his portrayal is what’s important, a determination to keep his skin tones from being a distraction is probably the most reasonable approach.

If you take control over other aspects of our photography, should you let the camera automatically select White Balance (WB) for you? Most if not all cameras come with an Auto-WB mode, and initially, as you learn to use the camera, it is perfectly okay to let it do its thing. However, as you perfect your camera skills and start taking control over the exposure triangle, you need to consider whether you want to leave WB to chance.

Yes, I said chance, because unfortunately, depending on your camera’s inner-smarts, from one situation to the next, the colors you end up getting due to the automatically selected WB setting may be a bit of an adventure. I suggest that you add a fourth corner to make an exposure square: WB, aperture, shutter speed and ISO. This will mean, however, that you will have to determine and set the “correct” WB. How do you decide this?

Methods for determining WB abound, but before we discuss them here and in future articles, let’s first examine a foundational choice for selecting the “correct” WB:

1. Do you want the colors to accurately reflect the scene as you photographed it, sometimes called achieving “actuality,” or
2. Do you want the colors to feel right, as in, for example, making sure that white is true white and not a color-cast version of white?

Just as with determining the correct exposure one first should decide how you intend the photograph to look, its purpose, so too you will need to decide whether you want actuality, namely an exact, accurate representation of the scene’s colors, or whether you want a different effect, as when you would want early morning sunlight to be a tad warmer because that fits the mood you want for your final image.

To keep things simple initially, let’s say you shoot for actuality. Most cameras have built-in WB settings such as Direct sunlight, Cloudy, Shade and Flash that you can switch to depending on the lighting situation at hand. Other settings usually include Fluorescent and Incandescent, which at least of my Nikons, I have found to be less than dependable, though I often choose them anyway to get me in the ballpark. For these and other more challenging lighting situations, such as when two or more disparate light sources are involved, other methods may be required.

The brute force method many use rather successfully involves shooting RAW, then adjusting WB in post-processing. This has both advantages and disadvantages. On the plus side, you can shoot now and ask questions later. On the minus side, you have to answer questions later, often without the benefit of being in front of the scene you shot to compare your WB adjustments against the actual scene. This is often acceptable, however. I have found through experience that color actuality isn’t as big a priority as some would make it. In the end, it’s about whether the photograph works as a whole, and color, regardless of how we may feel about it initially, is not always the overriding factor. Even if the image is about color, having less than accurate color isn’t necessarily a problem. Besides, probably half of us are color blind in lesser and greater ways and wouldn’t be able to agree on what the right color is anyway (think on that for a while).

When you don’t want to guess at color in post-processing, by far the most reliable way to set WB is with a pre-set shot against a gray (or white) card. Expo-discs and other like approaches essentially fall into the same category. Accuracy is a benefit of this approach, but it isn’t always practical, as when you are changing lighting conditions often during a shoot (now you’re shooting shady areas, now you’re shooting sunny fields), or when your subject is lit under light miles away, and that light source is not available where you are standing.

If your camera has Liveview and features the ability to change WB temperature, turn on Liveview and crank the WB until the colors you see in the LCD match the scene before you. This is quick and fairly trivial to do, but it also depends on the LCD’s color accuracy, which in the end makes it an approximation – though in my experience it is a very good one.

Hopefully this information will help you figure out how to set WB. Now you have to go back to those two options mentioned a few paragraphs ago and decide what WB you want to accomplish your goal for a given photograph. Stay tuned for future blog entries for additional suggestions and illustrations how one might approach WB selection to meet each photograph’s needs.

The question of whether to shoot in JPG or RAW, and what if any are the advantages of using the RAW format comes up often. The following is not a definitive proof of the benefits of one approach vs. the other, but a sampling of how “getting it right” in camera with JPG shooting works when compared to getting right or almost right in-camera with RAW, then following up with some post-processing tweaks. We will approach this by answering 3 basic questions: (1) How does an out-of-camera (OOC) JPG compare to a JPG resulting from straight-up, none-edited conversion from RAW in post processing; (2) How do minor exposure adjustments to a fairly well-exposed OOC JPG compare to a JPG resulting from the same adjustments on the RAW file; and (3) How do white balance (WB) adjustments on the OOC JPG compare to a JPG resulting from the same adjustments on the RAW file?

Equipment, setup and software used
Images were taken with a Nikon D80 and AF 35-70 f/2.8 lens, using the “Normal” picture mode and WB=Direct sunlight. A tripod was also used to ensure exact framing. Straight conversions to JPG and 16-bit TIF were performed in ViewNX without any adjustments. All exposure and WB adjustments were performed in Paintshop Pro X2, ensuring that the same adjustment was applied to both the OOC JPG and its corresponding TIF version. JPG files resulting from adjusted original files were saved using the same and high JPG quality settings in Paintshop Pro X2.

Comparison of OOC JPG against post-converted RAW-to-JPG version
To answer the first question, here are two sample image pairs. You decide what, if any, are the differences between the OOC JPG and the RAW-to-JPG converted (using ViewNX, in this case) versions. Please note that the OOC JPGs are going to be rotated as I did not want to make any modifications to the camera output (and saving JPG is a lossy process).

OOC JPG	ViewNX JPG

Comparison of exposure-compensated OOC JPG against post-converted RAW-to-TIF version
Now we start by toning down the highlights and adjusting midtones with the Highlight/Midtone/Shadow (HMS) tool, then adding a little contrast with Unsharp Mask (USM) as I prefer doing to some of my images to add pop; and I do this both with the OOC image and the RAW (after 16-bit TIF conversion in ViewNX).

Edited OOC JPG	Edited TIF

Since the exposures we’ve seen were a tad clipped in the highlights, I took a second set of sample pairs, this time with -0.7EV of compensation. Here are the OOC JPGs, prior any adjusments. As you can see, the highlights are in better shape, but the shadows and midtones are under-exposed and dull.

OOC JPG 1	OOC JPG 2

Comparison of WB and exposure-compensated OOC JPG against post-converted RAW-to-TIF version
And here they are after using the HSM tool to bring out the shadows and lighten the midtones a bit, and some USM contrast added in. I would point you in particular to the color/shade transitions in the blue tile for the first sample pair and to the color/shade transitions in the red petals of the second sample pair. See a difference, and if so, is it significant enough for you?

Edited OOC JPG	Edited TIF

Finally, we look at the third question and adjust WB to better resemble the colors in the scene. We do this with the images taken with -0.7EV for the first sample pair, so we also have to add the exposure adjustments discussed above. Again, look for color transitions, and if you are so inclined, go digging through the shadows in pixel-peep mode and see what you find.

OOC JPG	ViewNX TIF

This is a controversial subject and one where expressing any hard conclusions is bound to be unproductive in the face of what is ultimate a matter of preference for many digital photographers. I will say that given these very mild (low contrast) and unchallenging (regarding exposure) images, even the subtle differences I can see are enough for me to continue shooting and enjoying the benefits of the RAW format. I will try and come with additional samples, and if anything more significant than these results comes of it, I will follow-up with a future blog entry.