civilized ku # 2025 ~ on the subject of blue/cyan
Wednesday, December 21, 2011 at 10:54AM ;)
Walkers and steps ~ Oratoire Saint-Joseph du Mont-Royal - Montreal, CA • click to embiggenOn the subject of blue/cyan Colin Griffiths wrote (in part):
... I've never been quite sure whether the particular camera sensors I use boost cyan somewhat and that it then looks unrealistic/unpleasing to my eye on a print, or whether it's just a preference of my own ...
I can not state, with any certitude, whether or not digital sensors of any stripe "boost" cyan. However, I would assume that one of those camera review sites out there might just have that info on various camera/sensor combinations. That said, I would also suggest that differing RAW conversion software also contribute to how cyan as well as other colors appear. So, IMO, sensor/software variances with respect to cyan (or any other color) is what it is and the real trick is developing a conversion / processing methodology to deal with it.
Sensor/software issues aside and in my experience (IME), the real issue with cyan and, to a lesser extent, blue is the fact that under certain natural light conditions - cloudy overcast and bright blue-sky days, to name just 2 - there is a lot of "hidden" cyan/blue light lurking about. That is to say, "hidden" in the sense that the human eye doesn't see it, at least not in the way an non-human sensor records it.
That being the case, I am always on the look out, when converting / processing my pictures, for what I would call a cyan/blue bias. That is to say, cyan/blue that is out of whack with the way the human eye - my human eye - saw a scene. When that bias is detected, I most often apply a bit of selective cyan/blue correction to those parts of the picture in which it is visible. Rarely do I ever attempt to correct the bias with a global WB adjustment.
The reason why I choose to perform local corrections over global corrections is simple - IME, I have found that applying enough global WB correction to correct the cyan/blue bias most often creates another color bias, usually in the red/yellow spectrum, which is as equally unacceptable to my eye and sensibilities as is the cyan/blue bias. Case in point ...
... the walkers and steps picture in this entry was made on a dark overcast day with lots of cyan/blue content to the light. What this resulted in was the camera/sensor recording a rather extreme cyan/blue bias in the new construction - the stairs and foreground walking surface - part of the scene relative to the old construction - the building facade - part of the scene. Trying fix this bias with a simple global WB adjustment in the RAW conversion software resulted in the facade appearing considerably too warm.
There were a couple of ways I could have handled the issue. I could have converted the file twice - one conversion with WB for the steps and foreground, the other with a different WB for the facade - and then blended them in Photoshop. This solution would have been relatively easy to execute because the the blending step would not have been very difficult given that the dividing line between the warm and cool segments of the scene was not very complex.
Or, in the RAW conversion software, I could (in fact, this is exactly what I did) find a reasonably balanced WB setting, albeit a little too cool in the foreground and a little too warm on the facade, and also make (again in the RAW conversion software) a few color curve adjustments to mitigate, but not eliminate, the cool/warm color imbalance. After the conversion, in Photoshop I could then make a feathered selection which separated the cool zone from the warm zone and go to work on each zone (one after the other) with a combination of light color curve corrections together with a bit of de-saturation adjustments in order to bring each zone into a correct color balance.
QUESTION Why go to all this, what some my call, "trouble"?
ANSWER My printed pictures* are highly regarded, amongst other considerations, for their color characteristics - clean natural color which mimics, inasmuch as the medium and its apparatus allow, the manner in which the human eye sees the real world. I did not come by the expertise to accomplish this overnight.
That skill came from decades of making color prints in the wet darkroom, color prints made to very high commercial client standards and demands. Most of those color prints were intended for reproduction on a printing press, so part of my learning experience was also devoted to making very high quality prints which were well suited to the demands of the reproduction process (I spent a lot time in pre-press departments). That color print making skill was most often different from the skill required to make color prints for display / exhibition. In either case, knowing color and how to print it accurately for the intended end purpose is of paramount importance.
Needless to state (why is that phrase used when, in fact, something is about to be stated?), all of those skills are very applicable - minus the wet stuff - to processing files and making prints in the digital darkroom. Consequently, I was able to make the leap from the analog domain to the digital domain like a virtual duck to virtual water.
In any event, and all of that said, my point in all of this is simple - a part of making good pictures is understanding the fact that a printed picture, whatever its noted referent and connoted meaning might be, is an art object in and of itself. As an example, while I am not partial (with reservations and exceptions) to Sir Ansel's B&W pictures (although I do respect them from an historical perspective and, FYI, I really do like his color work), I would love to own one of his B&W prints because I am certain that, every time I looked at it, my eyes would water/bleed (in a good way) due to the sheer beauty of the object itself.
So, if you consider yourself to be a serious picture maker but you're not serious about making prints (that is, learning and implementing the craft of image processing and print making) or (worse yet) do not make prints at all, IMO, you're not a serious picture maker.
•what you see on your screen may or may not approximate (at best) what one of my actual prints looks like. There are just too many variables inherent in the screen viewing world - monitor calibration or lack thereof, the color temperature and the intensity of the light falling on the screen, or even the color of the walls in the room where the monitor is located, to name just a few.
Reader Comments (4)
Mark: "hidden cyan", that's a good explanation for what I must see on my monitor as I just can't relate it to my memories of the physical scene. I guess it may be a bit like why we used to use UV filters in the old days. Either way, I just accept it and as you write, I just get on with it. I'm not as skilled as you are, but I too don't use global colour corrections either, rather selective colour adjustments but not as carefully as you. Your explanation is making me question my own methods though because I certainly don't make the exacting demands on myself as you do. You did cheer me up in one respect though, I certainly do make prints. Perhaps I can call myself a "serious picture maker"! In fact, unless I've managed to produce a print with which I am completely satisfied, I don't trust myself to have optimised what I see on the screen. I just can't allow myself to complete the process without making prints.
I have a problem with the second half of your very helpful explanation though. I really admire your images, which as I've commented before, have influenced my own photographic development a good deal (though it might not show!). I have a new project in mind for next year (possibly a photo book :) ), which involves photographing local unremarkable agricultural land that may well disappear beneath a huge housing development. I want my pictures to express what I like about the area, but not to be too glossy (if you know what I mean). I also want to create an interesting record of pictures that might be of significant interest in the future. I just haven't worked out how to achieve a look that won't look boring to less visually literate folk (and I don't mean that in any elitist or snobby way). Sorry about the lengthy comment, but I did appreciate your post and it has made me think, so thanks.
Any tips for those of us who suffer from a degree of colour blindness?
A couple of comments/questions:
First, why is it that so many of your pictures that feature sidewalks or other man-made surfaces look so perfect? Knowing your insistence on "natural" you are obviously not "fixing" imperfections. But those surfaces looked painted-on, or bleached, or unreal.
Second, regarding the wet darkroom. I have only made a few color prints using a wet process, but I have no idea how you would make local adjustments. Sure, global adjustments are made with the addition of color correction filters, but beyond that, for me it was only following the "recipe", very unlike what I could easily do with black-and-white. Was it possible to dodge and burn with filters?
Mark, thanks for writing about colour correction. Your articles over the last few years on this topic have really woken my eyes to this issue and my images are so much better for it.
As an aside, I find my skills / vision is slowly improving. The improvements alternate between gaining an insight / skill when shooting and gaining an insight / skill during post. The two play off each which I find very interesting and satisfying.
Photography appears to be a simple hobby but artists like yourself help educate the rest of us how much depth there truly is in photography. Much obliged.