The Colour Red

musicaleCA · Jun 24, 2009

Tends to get over-saturated in-camera sometimes. *grumble grumble* I've run into this problem, and the issue I have is mostly with losing detail in solid red-coloured garments or fabrics while I'm shooting. Here are a couple examples:

All shot RAW, with a Canon 450D and EF-S 17-85mm IS USM (gratuitous CA removal; thank goodness I don't get noticeable pincushion distortion on this lens).

ISO 100, 85mm (and some serious cropping; didn't think I'd want my telephoto in the middle of a crowd

), f/5.6, 1/200, daylight, sun somewhere above and behind her (I think...sorta), though cloud cover (that much I'm absolutely certain of).

ISO 200, 75mm, f/5.6, 1/100, daylight through cloud over and on-camera fill flash bounced off a LumiQuest QuikBounce on ETTL at...probably around -1 2/3 or -2.

The question really is, can I correct for reds in-camera, or should I just desaturate the red channel in the areas that are over-saturated to bring back detail?

Garbz · Jun 24, 2009

This is exactly the type of thing camera profiling is designed to fix. What RAW converter are you using? I find for instance Lightroom using the "Adobe Standard" profile brings the colours under control that are typically a bit over exited on the Nikon D200.

Have a play with the DNG Profiles editor DNG Profiles - Adobe Labs Don't worry it works even if you don't use DNGs. Try reducing the red primary slightly but watch your skin tones.

musicaleCA · Jun 24, 2009

Oh darn, camera profiling. I was hoping to avoid that. >.<

I'm using Lightroom. I just tried playing the "Camera Calibration" in the Develop module; I assume that's what you're talking about? In that case Adobe Standard is...I suppose the term is over exiting...the reds compared to the "Camera Faithful" preset. Then again, ACR 4.4 gives me brilliantly saturated and detailed blues, with no change to reds. I'm using the second shot to test this. Anyway, is that the camera profiling you're talking about?

And thanks Garbz. Always manage to learn something from your posts, it seems.

Perhaps I should tinker with profiling the camera myself? Or maybe stick to "Camera Faithful"? (That setting really nabbed some detail back from reds but left the entire image looking a little desaturated and underexposed by comparison.

)

Garbz · Jun 24, 2009

That's what I'm talking about. Those settings load the DNG_Profiles provided by Adobe for your camera. Now these profiles can actually be edited (outside of Lightroom) using the tool I linked to. This allows you to adjust all the colours as necessary and it is something you only need to do once. Cameras unlike printers and monitors don't drift.

Fire up the profile editor, play with the reds, save the profile. Select the profile in Lightroom, and then save your current Lightroom settings as the default and ignore it for the rest of eternity

musicaleCA · Jun 24, 2009

Duly noted. Thanks Garbz; you advice on everything regarding colour is truly appreciated.

Montana · Jun 25, 2009

Good info Garbz. I have read of this problem with others, but never encountered it myself until my last paid event. Shooting outdoor rodeo in horrid midday sun. I was only occasionally checking the single histogram display on the back of the camera and thought all was well. Downloaded at home and blown out reds all over the place. Put the card back in the camera and displayed the RGB histogram and sure enough....right in front of my face.....blown red channel. Of course, if I am "blowing" my reds, I doubt they are repairable. I still find this interesting and will be researching more.

I am not usually very user savy at these things, so I will be watching this thread as I try to get the camera profile thing done with what I have to use.

musicaleCA · Jun 25, 2009

Funny thing that I discovered while tinkering in the DNG profiler, was that the reds in those photos were over-saturated...because the blue channel was over-saturated. That is to say, desaturating blue brought back more detail in the reds than desaturating the red channel...*head spins* It's a very curious thing. I know I sent you a PM Garbz, but perhaps you can put your reply here?

My guess, is that it's because I was shooting in overcast; the light in general was actually kinda cool to begin with. Perhaps a correct WB would help more. (Okay, now I'm *really* thinking I ought to just buy a colour card. I mean, if I'm going to gripe over these details, I might as well do my best to fix them lest my head explode in annoyance.)

Garbz · Jun 25, 2009

We all know that blowing out all channels means a complete loss of detail, however blowing out just one or two channels starts introducing a colour shift in the blown areas. For instance when you take a photo of a forest against the sun you often see some leaves turning yellow. This is because the green channel is maxed out while the red channel is still rising causing parts of the image which don't appear yet to be over exposed to turn yellow.

That's just one example but the thing is this may be fixable in post processing using recovery / desaturation / exposure tools. Montana play around with the settings in CameraRAW / Lightroom and see if you can't fix those. Typically things need to be quite extreme before damage is done due to the very wide colour gamut and 12-14bit bitdepth of the camera. It really records a heck of a lot more than is displayed on the screen, so often clipping can also be a result of the RAW conversion.

Montana · Jun 25, 2009

Garbz, I don't have lightroom. I use ACR, convert to 16 bit and then I only have PS Elements 6. In 16 bit, I have control of most things, but have to convert back to 8 bit to use certain specialty tools. However, in ACR this is the profiles that I have. This is a screen shot off of my PC. Why do I not have any sliders?

This is ACR 5.2

Garbz · Jun 25, 2009

... You don't have any sliders ...

Err can someone with PSElements 6 confirm that this is normal for Adobe CameraRAW? I've never seen it looks so blank. If this is normal than it's a problem since you don't look like you have the choice of opening the file using a wider colour gammut which means that even from within Photoshop Elements in 16bit you would have trouble doing highlight recovery.

<confused>

Garbz · Jun 27, 2009

Just confirmed ACR for elements does not have slider adjustments for the CameraRAW profiles. The recovery tools are still there under the main settings though. Also the profiles can still be edited using the DNG_Profile editor from the AdobeLabs website.

Josh66 · Jun 27, 2009

Not just a digital problem...

I remember reading in a few books (before the digital age) that red exposes more than other colors... If you have a red subject, you can underexpose (how much depends on the film), and the red will be properly exposed.

In one of the books, it was suggested to shoot a color chart at varying levels of under/over exposure to know what colors need what exposure with the particular film you're using.

I suspect that it is much the same with digital, but you only have one "film" to deal with.

Montana · Jun 28, 2009

Garbz said:
Just confirmed ACR for elements does not have slider adjustments for the CameraRAW profiles. The recovery tools are still there under the main settings though. Also the profiles can still be edited using the DNG_Profile editor from the AdobeLabs website.

Thanks for the leg work Garbz. I have been researching it as well. I seem to have it more or less sorted out for now. I don't plan up upgrading to full CS4 yet, as Elements does everthing else I require at a fraction of the cost.